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Subaru Air Conditioning Explained

Typical Subaru Air conditioning Problems explained.

The Air conditioning (AC) system in your Subaru is made up of the following.

A compressor, Condenser, Evaporative (Evap) core, Expansion valve, receiver dryer, hoses and lines, thermo sensor and the controls.  Inside the car there are a series of ducting or blend doors and their respective controls.  I am not really going to give a class on how the ac system works I will save that for another article.

Anytime you notice a situation where the Ac system isn’t blowing cold air, there is some sort of a problem with the ac system.  Driving down the road at 60 mph brings in a rush of air that may feel cool to you, just like standing in front of a box fan in your house provides some temperature decrease.  But if the ac doesn’t actually feel cold there is a problem.

When the ac system is in fact not performing as it should a diagnoses must be performed.  When an ac system has a low charge the performance will most definitely suffer.   But its also possible to have a ac system that has a full charge and not blow cold as well.  The possibilities are many and in some circumstances the problem may be hard to diagnose or have more than one issue.

Adding to this is that it is normal to lose about 2 ounces of R134a out of an automotive system every year with no real leaks.  So on the one hand the system could just be low enough to not function correctly after 4 years with no real problems or it can be low as a result of a leak.

I wanted to point out some of the current issues we see.

The 2000 to 2004 Legacy and Outback suffer from leaks at the 2 Ac hoses one from the compressor to the condenser and one form the compressor to the Evap core.  This causes the system to run low or empty.  It’s a very correctable situation and if not fixed properly will just cause the R134a gas to leak back out causing the problem you were trying to fix to reoccur.  To find the leak test equipment is needed.

2002 to 2003 Subaru Impreza, ( all models and trim levels) has an issue where the Evap core can ice over as a result of a design issue to the system, Subaru has issued a service bulletin about it.  The fix is a new thermosensor (which is located in the Evap core).  This requires taking the Evap core out of the vehicle which is partially removing the dash components on the passenger side.  I usually suggest replacing the expansion valve at the same time.

The 2001 to 2004 Outback with the H6 has some of the same leaky hose issues that plague the 4cylinder models.

The newer Ac systems (2005 and up) are smaller than they have been previously and even just a slightly low charge can affect the performance.

Typically speaking we only think about the Ac system when it isn’t working correctly, but the reality is, it really should be serviced at least every 4 years.   As the system loses some of the refrigerant as part of what is considered normal, it is replaced with air, which creates moisture in the system, which periodically needs to be removed through a process called evacuation, which involves hooking up a vacuum pump and putting the system into vacuum, the system should than be re-oiled and recharged with refrigerant and this good maintenance can help ensure your ac system will work when you want it to.

Thanks for reading

Justin

About the Author

All Wheel Drive Auto is a unique independent Subaru service & repair facility. We combine years of dealer experience with a local neighborhood shop atmosphere. We use Subaru parts & test Equipment and have the expert knowledge to fix it right the first time.

Comments (280)

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  1. Robert says:

    In your article you state that the 2000 to 2004 Outbacks suffer from leaks at the A/C hoses from the compressor to the condenser and from the compressor to the evaporator which cause the system to run low or empty, and that 2001 to 2004 Outbacks H6-3.0 have some of the same leaky hose issues. I am the original owner of a dealer serviced 2002 LL Bean wagon with 100,550 miles.

    I am wondering what the “…very correctable situation” is, and what the proper fix is to which you refer.

    I am unable to locate any relevant TSB or recall on this issue and would appreciate an elucidation of your findings on this matter.

    • Justin Stobb says:

      Hello Robert,

      Very correctable means it can be repaired, it isn’t overly hard, expensive or difficult for a Professional Technician to take care of. It wont cost thousands of dollars, take weeks and be hard to figure out.

      TSB’s cover less than 1/2 a percent of the issues we face on Subaru’s and are typically about Subaru alerting the Dealers when something is common to cut don’t on Warranty claim labor billed back to Subaru by the Servicing Dealer, so when things are learned after the cars are out of warranty you will never see a bulletin only safety recalls and a few notices if it affects a system that has the potential to be a safety issue.

      On the H6 platform from 2001 to 2004 both the low and high side lines/hoses tend to leak. You can look for oil residue at the crimp fitting areas of the hoses or if you have test equipment you can test for the leak.

      There are other issues we deal with such as climate control issues, leaks at the Evap core, compressor clutches that fail, relays etc.

      Justin

      • Chris says:

        I was quoted about $450 to replace the hose from the condensor to the compressor, $650 if I used any refrigerant with “stop leak” in it. The hose itself, from the dealer is $167!! That seems expensive to me.

        • Justin Stobb says:

          Stop leak is a terrible idea. Do you mean dye? I cant imagine a Good Subaru dealer suggesting any form of stop leak in any system you car has.

          As far as price, there is the ac service and the labor to replace the hose, not sure about the price on the hose either the MSRP went way up after the Tsunami in Japan.

          Justin

    • ward says:

      My 2004 Legacy has A/C which is nice and cold until outside temp goes over 85, then it will blow warm. After a short stop it will once again run cold.

      Dealer tells me it is the thermosensor. Trouble is it is on back order for over two months now. I think it is just that the clutch sticks when it is warm.

      Help! Its been a hot summer for not having A/C.

    • Terry says:

      I just fixed my 2001 LL Bean 6 cylinder AC. The compressor clutch would not engage. The system is smart enough to realize there was no freon left and would not allow the compressor to turn. I found the leak was the “o” ring between the low pressure hose and the compressor. Heat and age turned it hard and it wouldn’t seal anymore. I also replaced the “o” ring on the high pressure hose and added 2 cans of freon. Works great. Subaru part # are 73039TA020 and 73039TA040. $2 each

      • Justin Stobb says:

        Thats great,

        With the exception of a DIY not considering any R134A going into the Atmosphere if the system still has a charge when replacing the o-rings. Thats the only thing I want to point out here.

        Justin

  2. Mario says:

    Hello this forum is first rate.

    “The 2000 to 2004 Legacy suffer from leaks at the 2 Ac hoses one from the compressor to the condenser and one form the compressor to the Evap core.” Our car is 2003 Legacy GT

    This is my problem and talking to an AC mechanic mentioned you can replace o-rings vs the hoses. Do you agree? If not do you know the oem part # for the hoses to replace?

    Thanks again

    • Justin Stobb says:

      Hi Mario,

      The Subaru Dealer can look up the part numbers by VIN Number. Or you can look it up your self at opposedforces.com. Because the hoses tend to leak where they are crimped to the metal lines, your guy needs to look on the bottom side of the hose for oil residue. You may get through this year with just the o-rings but it may also leak out in a month, in my opinion because the hoses are so problematic its better to make complete repairs that wont let you down.

      Justin

    • Gene says:

      could I use JB WELD to stop a leak on an AC hose?

  3. Edwin says:

    If the a/c compressor is on with the a/c buttom off and the fan off,
    What can cause that problem?

    • Justin Stobb says:

      Hi Edwin,

      The ac compressor also engages whenever the defrost mode is selected. If thats not the case then the switch could be at fault, the relay could be sticking or the compressor clutch could be gapped to closely and as a result not disengaging properly.

      Justin

      • Eric Brecht says:

        I am having this issue with my wife’s 2004 Outback. The AC and the defrosr run intermittent. What is the underlying cause?

  4. Pete says:

    Hi Justin,

    I’m installing a new receiver-drier in my 2002 Outback. The Haynes manual recommends adding ~10ml refrigerant oil to the new unit before installing. Does it matter which side I add the oil to (from condenser OR to evaporator)?

    Thanks

  5. Greg says:

    in my 02 WRX, the refrigerant leaked out and line from compressor to condensor was leaking. I replaced both the line and the compressor and recharged with the 16oz can of R134A from Autozone. The clutch does not kick in on the compressor even though there is pressure in the system. When I manually force the a/c clutch to (give the wire +12v) the line from compressor to condensor gets super hot. What is happening here? should the system be bled or put on a vacuum machine? please advise.
    Thanks

    • Justin Stobb says:

      Ac repairs in the driveway are tough and most likely wont last, you do need to evacuate the air and moisture from the system prior to recharging it in most cases. You may have a pressure build from to much air or a pocket.

      Justin

  6. Aidan says:

    I have a 2003 Impreza Outback. I have been having a problem with the ac cutting out after driving for a while on hot days. The ac was left on, even though the fan was blowing warm air. The coolant temp spiked and then cooled off after turning off ac button. The ac works after car parked for a while then cuts off again after heating up. The rad is full. Both fans are working. Any ideas?

    • Justin Stobb says:

      The Ac system needs to be evaluated locally there is a TSB for the Evaporative core freezing on the Impreza Platform of that Era and some updated components, it is not a DIY repair.

      Justin

  7. Mike says:

    Hello! The A/C on my 2004 Legacy cuts out after 10 minutes or so of driving. I just had it serviced, there are no leaks, the freon and everything was replaced. The problem remains, when the engine is warmed up and you open the throttle, the pressure in the system decreases and the compressor turns off and stays off until you reset the A/C and wait for another 5-10 minutes. The A/C works fine at idle for a while, kicks off as soon as you start driving.

    • Justin Stobb says:

      Mike,

      There are many possibilities there is just no way for me to guess from here. There is no Freon its R134A, and an AC service doesn’t include everything, typically its no more than a preventive maintenance service like changing your oil. Overcharge can cause your symptom but so can a failed compressor clutch, I could go on like this for a page of could be’s, your’e just going to have to go back and have a proper diagnoses and take things from there.

      Justin

  8. tat2matt says:

    I replaced the high side hose in my 04h6 recharged the system and drove about 700 miles parked for 2 days and the system was empty. I drove home replaced the o ring and added some teflon type tape to the threads at the fire wall and drove it problem free for a month. I just drove 300 miles with the ac on worked great parked for 2 days and it was doa on the return trip. I understand the leaking hose idea but why when it works fine for a month will it leak out after a long trip?

    • Justin Stobb says:

      The leaks are brought on by pressure and flex, the more those things happen the more it leaks out.

      • tat2matt says:

        from this response it is implied that there is more pressure building up the longer you drive? that doesn’t make sense if that were the case then there would have to be a pressure release valve in the system and we would have to recharge the system like filling a gas tank.

        • Justin Stobb says:

          Ok, so here are some of the aspects of the ac system you are not familiar with. You can go buy a set of Ac pressure gauges and hook them up to your vehicle you would have a better understanding of how the ac system in your vehicle works at various speeds and temperatures. Ill do my best to try and explain it, but Its hard to teach you in a few paragraphs something you should spend a minimum of a few months in school for just to learn all the aspects of the AC and climate control systems before you will have a real good understanding of how it all works than spend 5 years in the field gaining real world situations before you are really an expert.

          Temperature affects pressure in your ac system just like it does in air your tire, which is why you always check and set tire pressure cold, as when the tire rolls down the road and heats up the pressure will increase do to the temperature increase creating expansion of the air.

          In your ac system you have a gas called R134A, pressure is built up as the Ac compressor compresses the gas creating a temperature increase and then the pressure is dropped rapidly the sudden drop in pressure is what actually creates the cool air, AC is NOT making something cold, its creating pressure and temperature and than drastically removing both.

          While driving down the road at a higher rate of engine speed the Ac compressor WILL build more pressure than at idle or driving around town. The Ac compressor will engage more frequently creating more instances of pressure build up, the car driving down the freeway at higher speeds will FLEX more than at idle while at a stop light.

          PRESSURE & FLEX CAUSE THE HOSES TO LEAK.

          There is a high side pressure relief valve that will cause the system to “vent out” the dangerous gas that is R134a but only when the system reaches a pressure that is to excessive, this pressure value is much higher than the normal operating pressures of an AC system. Typically only overcharging or a defective Expansion valve will allow the pressure relief valve to engage. The primary reason the Relief valve is there is to prevent explosion under extreme pressure, and since part of the AC system is in the Cabin of the car with you it would be bad to let the evaporator core explode while you were in the cabin with it , and in older cars could at the worse kill you. With out a relief valve pressure would continue to build and vent or explode out which ever was the weak spot in the system, and that could vary by the car.

          Again higher pressure at higher speeds is a Rule in an automotive AC system. But not above a specification to the point of Vent out just higher gauge readings and more frequent compressor on times.

          If you have a slow leak in a tire do you think it will leak out faster with more air in it or with less?

          The first thing you learn at tire store (if its a good one) is that when looking for a slow leak that is difficult to find, first inflate the tire to the Max PSI to find it, which poses no risk as long as the tire is not mounted on the vehicle and driven, and a cage is used if a split rim. As a leak wil show up more clearly at 50PSI than 30PSI, it has no choice its a a rule of pressure.

          Because R134A is harmful to the environment, we really don’t want it to continue to leak out. An Ac system that is low can also lead to AC compressor damage as well.

          I hope that helps you and any one else that reads

          Justin

  9. Justin Stobb says:

    Hi Kane,

    There are 2 hoses most likely the other one is leaking.

    Thats just a guess based on the info provided.

    Justin

  10. Pete says:

    Hi Justin,

    I recently had my 02 Outback AC system serviced (replaced receiver-drier and leaky discharge hose) and while the air is blowing cold and all seems fine, I’m now hearing a brief foghorn noise during operation and almost always when I turn the AC off. One suggestion is that the noise may be coming from the expansion valve. Any other possibilities? And if it is the expansion valve, can I live with it and the noise or must the valve be replaced ASAP (having to open the system again and replace the expensive drier, again!)?

  11. Brian says:

    Hey Justin,
    Thanks for the info. I have an 01 subaru legacy wagon. I drove it fairly hard for over two hours yesterday. As I was finishing my drive I pulled into a parking lot and scraped the bottom behind the front tire. I noticed a considerable amount of drip coming out of what looked like the frame on the passenger side of the vehicle just behind the passenger seat. It seemed to be water, no oil residue. I thought it may be a tube that was running down the beam and then I noticed a slight crack in the beam where the fluid continued to drip from. I left it at a mechanics in town and got a ride. Does the AC leak from a fabricated crack where the tube ends in the frame or is this something out of the ordinary that needs to be addressed. Thanks for any advice

  12. Alison says:

    Hi – I am really needing some guidance on my Subaru Outback 2005 A/C issue. During the span of one minute it will blow cold and then cycle very briefly to less cold or even warm (the hotter the day the warmer it blows), then back to cold. I have replaced the A/C fan as suggested by the mechanic, this did not fix the problem. It was also charged at this time and a dye was used to check for leaks. Nothing. The second time around the mechanic replaced the compression valve, stating that he too noted that the pressure would decrease during this warm cycle. He then also recharged it. Driving it today I can tell that it is better but when holding my hand up to the vent I can feel it cycling again – cold, then warmer, cold again. I anticipate that this problem will get worse as I lose this fresh charge. Which is exactly what happened the first time I took it in and got it charged. Any ideas?

    • Justin Stobb says:

      Hi Alison,

      I am afraid there just is not anything I can do from here, I need hi side and low side gauge readings and temperature values to try and diagnose an AC issue such as the one you have.

      Justin

      • Jim Geuin says:

        I had a similar problem with a 2005 Legacy. The A/C would cycle off for an extended period and then back on . . . brutal in the central Florida Summer. I took it into a Pep Boys in Coral Springs and a mechanic said he found nothing wrong with the system from an A/C perspective, but did find a badly corroded relay. He cleaned the relay and reinserted it and it ran great back to north Florida. It had been doing well around the city, but on a recent highway trip, it started cycling again. I am going to try replacing the A/C Compressor Control Relay Standard Motor Products RY-665.

  13. Amanda says:

    04 Subaru WRX Impress – My a/c blows air but does not cool. About 2 weeks ago I took my car in for an oil change and a/c diagnostic and they charged it up and said it was working fine but they put dye in just invade so they could check next time I bring it in for oil change. Well…it did not fix the problem. There is still no cooling happening. Do you think it could he hoses? I was also told by a non mechanic to find out if there is any internal fuses for the a/c and make sure they haven’t burned up. Is that even a possiblilty on this car??

  14. Ronda says:

    I have a 2011 Subaru Outback and am having A/C issues that the dealer cannot identify what to repair. I keep my dual-climate control system on 70 degrees all the time. Sometimes in the morning when I first start the car, the A/C blows hot air like the heater is on. The other day it took 40 mins for it to start blowing cool air and I did not change anything on the settings. Nothing is showing up in the memory as a sensor problem, the freon is not low, they can’t find an electical problem. When I first took it in for this problem, the freon was low and they said either there was a leak or they just didn’t fill it up at the factory. Now, the second time I took it in for this they can’t replicate the intermittent issue to find a solution. I just wanted to post and see if anyone else has had this problem and found a solution that I could share with my dealer. Thanks.

    • Justin Stobb says:

      Hi Ronda,

      When it is malfunctioning, does changing the Temperature make a change? Another words you start the car up and it blows heat do you try changing the temp on the Auto climate temperature control panel?

      I have not heard of this, but there are really only a couple of possibilities.

      Justin

      • George says:

        My 2011 does this too but there is nothing wrong with it. For me it was because the inside temp of the car was below the temperature setting on the climate control. If you just want cold air then lower the temp until it starts blowing cold air. The lowest temperature setting is ‘Lo’ and that will always blow cold air.

  15. Michael says:

    I have been a Subaru owner for few years now. Bought my first 2000 Outback in 2002 and just recently traded it and got a 2004 Outback and i am having weird A/C issues in the 2004.

    The A/C works fine most of the time but on long drives (30 + mins), making no changes to the vent settings or anything, the vents in the system all close. So one mintue with the A/C on full blast I have cold blowing air coming out of my main vents (the 4 accross the front of the car) and the next there is no air coming out of any vents BUT I can still hear the system blowing like crazy it’s just blowing in my dash. When it does this, if i press the A/C and turn off the A/C after about a minute or 2 the systems corrects itself it blows correctly but it is still a reoccurring problem.

    I have taken it to the guy i bought the car from and have even made a video showing what happens and he is very willing to help but he needs to see it happen and of course I can’t make it happen when i need it to happen.

    I am assuming it’s some sort of vacuum issue. have you ever seen this? If so how do i need to direct someone to fix it?

    • Justin Stobb says:

      Hello Michael,

      You didn’t let me know if its a 2004 Subaru Outback 4 cylinder or 6 cylinder and whether or not it has manual or Automatic climate control.

      Regardless its not a vacuum issue, its a mode control issue that will need to be diagnosed. If the mode selector is on AC and dash vents and it works and then doesn’t there is an intermittent problem with either the mode selector, Body Control Module, climate control module, mode door actuator, wiring etc.

      There isn’t anything I can offer you except to say its very repairable, not a common issue and will need a qualified Subaru Technician to get to the bottom of.

      Justin

      • Jon says:

        I’m not a pro but I can tell you that this is exactly the symptom from the Evap ‘freeze-up” in my 2003 WRX, a symptom which is more common in high humidity conditions (and temporary cure is to turn the heat on full for a couple of minutes.) I was charged $150 for a check & top off refrigerant at the dealer who DID NOT notify me about the sensor TSB which was issued for 01-02 built cars.

        • Justin Stobb says:

          Hi Jon,

          So there are many things that can affect the AC some intermittently some constantly until resolved. The TSB for the Impreza does not apply it uses different components.

          I am not sure I understand your complaint though did you still have an issue after the AC service was done that led to having the thermosensor relocated? The TSB wasn’t a free thing for many WRX owners by the way, it was a TSB not a recall. Meaning the purpose is to cut down on Technician times to diagnose a problem by making the problem and resolution of the available.

          Justin

          • Jon says:

            Thermosensor was never replaced, too expensive to consider, just corroborating symptoms on different vehicle of vintage near the TSB’d models. This vehicle later had to have the compressor replaced because its bearings went bad although it was still working. Now, after a few more months it is only cooling in defrost modes so I suspect a relay or other electrical glitch affecting 3/5 of the modes. At least I haven’t had a freeze-up since the rebuilt (from Subaru dealer) compressor!

          • Jon says:

            Well, I solved the new problem…after a 5k mile trip in my new Focus, I was pushing the rear defrost button instead of the A/C button, about twenty times on several trips before I saw a slight wavy pattern on the rear window and Looked at what I was doing (in my defense my hand at 3 o’clock did cover “A/C” and eyes stay on the road!).

  16. Will says:

    I have a 2008 Subaru Legacy 2.5, the a/c nor the heating systems blow any at all. Is this a fan issue or something more serious?

    • Justin Stobb says:

      It could be the blower motor/ fan or just a blown fuse plus many other things as well.

      Its difficult to speculate without information like there is power to the motor but it fails to come on, or there is power but no ground signal. Anotherwords you or someone esle will need to delve into whats the cause of the malfunction.

      Sorry I cant offer more.

      Justin

  17. Ralph says:

    The air conditioner on my 2004 Legacy 35th Anniversary Wagon did not cool well when it was over 80 degrees, for 5 years. The repair guy couldn’t find a problem, system had the right pressure. He suggested he could try adding a half-can of refrigerant, which he did, and it has worked well on the hottest days since (now April, 2012).

  18. Davd Johnson says:

    I have a 2001 Outback Legacy wagon, base model, 4 cylinder with automatic trans, manual cabin temp controls, 168,000 miles. I am original owner. Never had any AC problems until now. No AC preventative service has ever been done, not even a can of AC gas added. It will not get cold, I don’t think the compressor is coming on at all. Blower is fine, blows at all speeds selected. I have noticed that it sometimes will suddenly get cold if I have been driving a while and when that happens I hear a noise like a water draining through a pipe. It comes from the cabin right front footwell, which I guess is where the coils are that the air blows across. It did this just a few times, but seems to have stopped completely from getting cold.

    I also had a 1985 Subara DL sedan from new until 1993. I remember the AC on this stopped blowing cold suddenly several times and the fix was always to have an electrical relay replaced. Probably happened at least 3 times in 8 years. I have been trying to find if there is a relay on my 2001 for the AC but all I can find is the fuse in the cabin fuse array, which is fine.

    I am tempted to just add a can of refrigerant to see if it is just low pressure after 11+ years. I used to do this with my dad in the driveway way back. If that doesn’t work I will probably just take it to a dealer. I plan to keep the car for while longer for teenage drivers.

    Thanks for all your posts.

    David

    • Justin Stobb says:

      An Ac service really should be done every couple of years, if its not working now its most likely low or empty due to a leak.

      You can try adding a can of R134a your self, but if its short lived and you dont have the test equipment, or the ability to diagnose why its not working, its probably better to let someone else have a look. I will add the venting or leaking out R134a is not a good thing.

      Justin

      • David Johnson says:

        Still working on the 2001 Legacy Outback wagon. I bought a can of R134A that came with a simple low-side pressure gauge. It showed no pressure and took the whole 18 ounce can. That brought up the pressure but not into the “green” on the gauge (adjustable for ambient outside air temp) about 20 PSI if I remember right on a 75 degree day. The compressor kicked in after the pressure rose and it started blowing cold. It was not always blowing cold, so I added another 12 ounce can of R134A, which still did not bring the pressure all the way into the green. It was blowing cold more often, but still takes about 10 minutes to get cold, stays cold for about 10-15 minutes then starts blowing warm again. I pulled the relay and it checked good for continuity both with and without 12V. I haven’t seen anyone talk about that, found that in a Subaru tech manual on a CD I bought several years ago off of ebay.

        Do you think this might be an “air in the line” problem? I don’t want to add anymore R134A. I am about to finally give in and take it to a shop.

        Thanks for your help.

        David

        • Justin Stobb says:

          If it works when you add more R134a its not going to be anything electrical such as a relay or a switch.

          You most likely have a leak, that needs to be repaired than an ac service performed. Unless you posses the proper leak detection equipment you will not be able to find most refrigeration leaks.

          Justin

  19. Lee says:

    I have been having problems with the AC in my 2008 Tribeca for over a year now. Fortunately (or unfortunately depending on how you look at it) living here in the PAC NW I don’t use the AC very much, so the problem may have existed for much longer. I took it in to the dealer last August and was told that coolant was empty, it was recharged and worked for the rest of the time I needed it – probably a week. This spring, again it wasn’t working (not blowing cold air), so I took it back in. I was told that the suction fitting at the compressor was leaking. The hose/o ring assembly was replaced and the system was recharged. Again it worked when I picked the vehicle up from the shop, but the next time I tried to use the AC (about a week later) it wouldn’t get cold. I returned it to the dealer and this time I was told that the problem was an intermittent power relay, which was then replaced. The AC worked when I picked the vehicle up (yesterday), but today, again, stopped getting cold and now only blows warm air. I purchased the vehicle in another state before moving to my current location and it is being serviced under the extended warranty plan. How likely is it that the service department isn’t trying very hard because I purchased the vehicle in another state and the work is being performed under the extended warranty plan? Am I just getting the run around? Thanks for your help.

    • Justin Stobb says:

      Hi Lee,

      Ac is actually the single most frustrating system to diagnose sometimes. You can have a small leak that is very difficult to determine the cause or multiple slow leaks that show up one at a time, an electrical issue with the automatic climate control system and than the market place just doesn’t allow for proper time for a proper diagnoses with everyone trying to perform Ac services and the average driver not understanding all of the complexities. Then yes, when you add a warranty company to the mix it can add a entirely different element to the diagnoses in the way of who is paying for it. It doesn’t sound to me like that’s exactly whats going on in your situation but with Jiffy lube offering cheap ac services, it has made it very difficult as a shop to get paid to properly diagnose a problem, when there is one that is not straight forward.

      I am not aware of any typical issues with the Tribeca which is most likely why its been such a back and forth situation for you. I would make arrangements with the Service department and state you “don’t want it back until its perfect”.

      I hope that helps, and It can be fixed.

      Justin

  20. Jason says:

    I have a 2000 Subaru Outback with 194k miles on it that my wife drives. Not knowing anything about AC and the need for maintenance every 4 yrs, I never did anything with it (bought the car at 112k miles). Recently, the AC decided to quit.
    I put the dye in the system and found where it was leaking and since the one O Ring had gone bad, I just replaced all of them, and then filled with refrigerant. It held, but blew hot. The manifold gauges read low 40/high 50. I did some research on the net and it said that the compressor was likely bad. I ordered a used compressor online (90 day warranty) and installed it. A friend loaned me a Harbor Freight vacuum pump and I sucked the system down for about 15 minutes, then filled with refrigerant. This time the low side showed 40 and the high side showed about 45. The clutch on the compressor engages but it still blows hot, and from what I’ve read the pressure needs to be around 150 or more on the high side. Outside temperature was about 75 degrees at the time. I let the AC run for about three minutes and checked the pressures again, and this time the low side had dropped to about 35. I also heard a low hum/hiss from inside the car coming from the vents.
    Bottom line: my pregnant wife is still driving around in a hot car. Any ideas? After reading your post and several other things on the internet I’m not as concerned about the low side dropping as the car was on and it seems like that may be normal, but my high side is definitely wrong. From my internet research it appears that this car uses an expansion valve rather than an orifice tube, and I can pull it apart and check to see if that is bad (I’m assuming its behind my dash?) and maybe the evaporator is leaky? Any help would be appreciated.

  21. Jennifer says:

    Your article states: The 2001 to 2004 Outback with the H6 has some of the same leaky hose issues that plague the 4cylinder models.

    I own a 2002 Subaru Outback that’s experiencing air conditioning problems. Since this seems to be common knowledge, was there a recall? The dealer is quoting $375.00 to repair.

    • Justin Stobb says:

      Hi Jennifer,

      Recalls are typically about Safety items, and lets face it non functioning Ac while inconvenient, is far from a safety issue.

      Most makes and models will need some ac service after 5 years, $375.00 is not a lot of money to have to spend after 10 years of service out of the AC system.

      Hope that helps

      Justin

  22. Neil says:

    I am trying to help my son out with the air conditioning on his 2002 outback. I noticed the clutch was not engaging. I traced it back as far as I could. There is power at the relay and when I jump it to B+ the clutch enables. He was going to have it serviced but I figured we would try and fix this before he took it in for leak testing and save a couple of hundred bucks on diagnostic time. I cant find a wiring diagram anywhere and I do not know what else would dis engage the clutch. The fuse is good. I am guessing there is a temperature or pressure switch somewhere to check. Any ideas?

    • Justin Stobb says:

      The wiring diagram is in the Service manual.

      You will need to determine source of voltage loss to the Clutch, there are to many possibilities to go over each one with you in this forum..

      Justin

  23. steve says:

    Just as an FYI. For almost a entire summer my 2004 subaru forester was having intermittent a/c issues. It would blow cold air when I first started the car with a cold engine but as the engine began to get hot after driving for a while it would start blowing hot air out the vents. The problem steadily get worse as the outside temperatures got hotter through the summer. I tried charging the system but that didn’t work. I looked to see if the a/c clutch was engaging and it appeared to be but I couldn’t really look when it was blowing hot air as it usually happened while I was driving. Then I bought a set of manifold gauges to make sure the system was indeed properly charged and that the clutch was cycling on and off at the proper pressures. Again it appeared to be working correctly but it was hard to tell because I couldn’t check it when it actually blew hot air out the vents. I checked the a/c clutch air gap which was at the outer limits of the specification but still within spec. I checked the a/c relay for proper function and it too was working fine. I then ran a jumper wire from the positive battery terminal to the a/c clutch electrical connector and took the car out for a drive that usually would have caused it to blow hot air and the vents blew cool air the whole ride. This helped me narrow the problem to the a/c clutch itself but I checked for voltage drops in the a/c clutch circuit and was unable to find any significant drop. At this point I was sure the clutch itself needed replacing but I was unable to find a replacement clutch for sale. Subaru itself recommended replacement of the entire compressor if the clutch didn’t work properly or even if the clutch air gap was too large. Paying $400-500 for a new compressor and paying someone to evacuate the system so I could replace the compressor was not really an option financially so I kept looking for other solutions to the problem. Eventually I found a thread on a subaru forum saying that there is actually 2 shims between the end of the shaft the clutch is splined to and the a/c clutch itself and that 1 or both of these shims could be removed to decrease the size of the air gap. The reasoning behind the need for this was that in hotter weather the extreme underhood temps decreased the strength of the magnetic field created by the electromagnet in the a/c clutch preventing it from being able to close the larger air gap and properly engage the a/c compressor pulley. This seemed to make sense and since it would be pretty much free, I decided to give it a try. After attempting to rent/borrow an a/c clutch puller I found the ones at autozone and advance auto did not work on my subaru’s a/c compressor and although pep boys had the proper tool it was already rented out at both my local pep boys. I wound up making my own puller which actually worked quite well and after getting the a/c clutch off I initially removed both shims and replaced the clutch. This turned out to close the gap too much and once the clutch had engaged would no longer disengage to cycle the a/c on and off properly, although by my measurement the air gap was just below the lower limit of the spec. Once it had been engaged it wouldn’t disengage until I either turned off the car or disconnected the clutch electrical connector. At this point I removed the a/c clutch again and replaced the thicker of the two shims and reinstalled the clutch again. I then measured the clutch air gap and it fell right in the middle of the specification and I have not had a single a/c problem in the 3 years since. Just thought I would offer that knowledge up to anyone having similar problems with their subarus a/c functioning intermittently in hot weather.

    • Justin Stobb says:

      Compressor Clutch gap is something an experienced Tech should look at if the determination was there was a signal to the Clutch but no engagement or it wont disengage either..

      Its good you were able to avoid the Compressor expense.

      Justin

  24. Henry says:

    Hi Justin

    I’d 1st want to say thank you for all the responses. You are very knowledgeable and courteous in replying to all the questions.

    I have a 2008 Impreza and when I turn on the A/C it works then after a few minutes (even though it is still “on”) there would be no cold air. I’ve had it diagonosed by a dealership and examined by a trusted mechanic. Neither were able to find a problem. The fre-on was re-filled which made the system less prone to this “on/off” scenario. But it still occurs.

    Have you experienced anything like this or know what I should tell my machanic to look at?
    I’ve love to take my car to you, but I’m not in the Seattle area (actually I’m in Toronto).

    • Justin Stobb says:

      Hi Henry,

      Yes we have seem that issue but the fix was different each time, I dont have enough information at this time to be of much help. It could be an electrical issue, a blend door issue or a mechanical issue with in the Ac system it self. If it didn’t act up for the shop when you had it in it would be hard to determine the cause, but if it did act up im not sure why it couldn’t be diagnosed?

      Does it act up all the time every day or is it more intermittent than that?

      Justin

      • Henry says:

        Thank you for the response.
        It does act up daily. I’ll have the ac running then I can feel the compressor turn off (you can hear/feel the change in the engine). I was wondering if there’s a solenoid that would engage and disengage the ac?

  25. aaron says:

    So I have a 02 wrx just recently my AC stopped working. Compressor and clutch are working but the system isn’t getting cold, I checked my levels and I’m still charged. The only thing I’m hearing is a hissing noise coming from inside the the car any thoughts on what I need to do to repair or fix my system?

  26. Justin C. says:

    Hi Justin (great name!),
    My ’08 Impreza 2.5i has had some A/C problems for a few years. While it was still under the intial service plan I had with my dealer, I would have it re-charged every six months, or so, and things would work. They told me one of the hoses had a slow leak. Now, a year after the plan and the vehicle’s warranty have expired, I took it into my mechanic to have it re-charged again, but now the leak is much worse. They changed the hose, but the A/C kept blowing hot air. After taking the car back, they’re telling me that the Evap core is also leaking, and that the work + part to repair it will be around $900. At this point, am I better off taking it back to the dealer to have this work done? My mechanic can’t believe that a four year old car is having this issue, is it uncommon and I just have terrible luck? Thanks, I’ve enjoyed reading your comments!

    • Justin Stobb says:

      Hi Justin,

      Yes it is a great name and if you are under 40 you were named after me!

      It should have been repaired under the service contract, its very unfortunate they just kept adding more R134a.

      The Evap core is not a common leak, but we do see a few.

      If you have repair orders from the Dealership showing the constant refills and no fix you should call SOA, and have a conversation about a warranty repair not being handled correctly, they may even go back and audit the Dealership to see how much they were billed to not correct the issue. I think you have several arguments to make and should hopefully get some help.

      I imagine you must live in a smaller market? I just cant imagine a large Subaru dealership pulling anything like you have mapped out.

      Justin

      • Justin C. says:

        Thanks for the quick response!
        I’m in Northern Virginia.
        The entire time the dealer serviced it, the Evap core was never even mentioned. My mechanic missed it twice, thinking the hose was the main problem. What recourse could I have if my dealer claims the Evap core wasn’t leaking during the time period they worked on it?

        • Justin Stobb says:

          Im confused now.

          Did you take it to the dealer every 6 months and all they did is add more R134a? If you had to take your Subaru back o the Subaru Dealer every 6 months because the AC system was low, and there was never a documented repair for a leak Subaru would not like that very much. When I worked at a Dealer there was seldom any Warranty pay issued unless there was a defective part replaced, you could site one time the system was low, but if it was found to be low 6 months later there had better have been a repair documented before a AC service was billed to Subaru. If the Dealer was Good willing the top off every 6 months then you need to ask them why they never attempted to permanently repair it? If you have documentation the Dealer was topping it off that would be good enough I think.

          Now if you took it somewhere else to have the Ac recharged other then the Subaru Dealer there would be no record, and yes you would be on your own. You should not have paid to have someone recharge it while it was under warranty, and if a independent shop notices an issue its up to you to make an appointment to get it resolved.

          If the car came to my shop at say 30,000 miles and the Ac did not function as it should we would have inspected the condensor for rock damage (just behind the grille) if its damaged and leaking we would have given you a estimate to repair it (as a damaged condensor is not covered under any warranty), if the condensor was not leaking because a rock or the like had come in through the grille and caused a leak, we would not have performed any service to it, we would have instead informed you that your Car was still covered under Warranty.

          Hope that helps

          Justin

          • Justin C. says:

            Thanks, sorry for confusing you. The A/C started acting up right at the end of my service plan/warranty. At a scheduled maintanence, I asked them to take a look at the A/C and they recharged it. Two services later (ironically the last that was covered by my plan), they did it again when it began to blow hot air. The service in between was during the dead of winter, when I hadn’t used the A/C in quite some time. It actually worked all of last summer after that second re-charge. Once it started getting warmer this spring, it wasn’t working when I began wanting to use it again, and that’s when I took it to my independent shop mechanic and got my current diagnosis.
            I’m guessing my dealer would have records of the services they performed? I think I have my copies, but not sure if I have them all.

  27. Jimmy Brickler says:

    This forum is amazing. I have a 1997 legacy L wagon, 2.2L. I need to replace my AC compressor and clutch. I have three questions: 1) Used compressor/clutch with warranty – do smart people take risks with used compressors? 2) Do the 2.2L legacies share similar AC components with 2.5L Outbacks and GTs? (for swapping purposes) and 3) Do you do any paid phone consultations for some unrelated subaru performance questions? I’m in California. Thanks!

  28. Greg S says:

    I have a 2012 Subaru Impreza and my A/C compressor turns on and off every 30 seconds or less. As I have never noticed this in any other vehicle I have owned or driven, I feel this shouldn’t be happening. Whenever it turns on it makes a loud click/hissing noise, which is accompanied by a loss of power to the engine and a slight accelerator movement at my foot. I can sometimes hear the noise when I have music playing, but usually have my music loud so I don’t have to deal with the noise. I went to Subaru to discuss this and they say its normal, but why would a brand new 2012 car do that? It gets really annoying on long drives, which I do quite a bit. Suggestions/Thoughts?

    • Justin Stobb says:

      You could potentially have an aggressive compressor clutch gap causing the noise, in which case the fix would be to use it. But you haven’t really described anything unusual.

      Have you tried putting your mind at ease by driving another one?

      Justin

      • Greg S says:

        Yes the aggressive clutch gap sounds like a possibility, because the sound is quite an aggressive noise. What do you mean the fix would be to use it? As in the more I use the A/C the quieter the sound will get or will the sound/feeling just go away from use?

        I have tried driving another one, it made the sound, but it wasn’t as aggressive.
        I just find it odd that a brand new car makes that noise, while my old 2001 Nissan Sentra never made the noise, or consistent loss of power, 1999 Ford Taurus didn’t, and I can list a few more that didn’t have the same noise or reoccurring power loss sensation. Its unsettling knowing I will have to deal with a “bumpy” ride in a brand new car that I spent quite a bit of money on for a car with a supposed comfortable ride.
        I don’t mean to come across as complaining, but I thought if I spend 30k in our times (2012) that I would get a product that drives comfortably and doesn’t have an A/C compressor that turns on and off every 20-30 seconds, reducing power, and making an aggressive annoying sound, and now allowing me to fully enjoy my Subaru as I had hoped.

        • Justin Stobb says:

          Greg,

          I have never observed a 4 cylinder car that did not lose power when the AC engaged, The 2001 Sentra you mentioned did that, I know, I worked at a Nissan-Subaru Dealer as a Technician for years I know the 2001 Sentra as well as I know the 2001 Outback. You must have owned the only one that didnt. The power sensation will be more prevalent on a AWD vehicle than a 2wd vehicle and the load that’s already on the engine will dictate the power loss when the load is increased when the AC kicks in

          The Ford Taurus most likely had the 3.0 or 3.8 l 6 cylinder and is hardly a comparison.

          The ac engages based on pressure and temperature and disengages for the same reason, when a pressure value is met.

          Not sure how the ac coming on is causing a bumpy ride.

          If you think there is truly something the matter with your 2012 Impreza you need to contact SOA if you didn’t get any where with the Dealer. Ask for a Rep to meet you at the Dealership, show him your concern, let Subaru tell you if its normal , compare a few cars.

          Did it do this on the test drive before you bought it? If no when did it start and you need to communicate that to Subaru the day it started, if yes why did you buy it? Regardless, this is the first I have heard of this, we have serviced several, my In laws own one as does a very close family friend I have spent a lot of time going over the 2012 Impreza as it had a lot of new technology and I wanted to stay current, I have again not experienced anything so radical on any of the 2012 Subaru Imprezas I have driven.

          Justin

          • Greg S says:

            Yes, your right. Both cars, and all do lose power once the A/C is turned on, just this vehicle is the first where I feel it cycle every 20 seconds. During the test drive I never really paid attention to see how the A/C effects the drive, because I never thought it would do so as much as it does.
            I wouldn’t say its a bumpy ride, but I would say the sensation is one of a person shifting gears in a standard vehicle every 20 seconds. (I timed it)
            I have had a few friends drive with me, and drive the car and they say they have never felt a car do that every 20 seconds, only on the initial turning on of the A/C.
            I have a check up scheduled this week so hopefully they can give me a proper answer for this situation, and if not, I will follow up with SOA and see what can be done.
            Thank you for your help and advice.

      • Greg S says:

        And I understand there is power loss whenever you turn the A/C on, which I did experience in my other vehicles, but not as a reoccurring cycle every 30 seconds, which I experience in my ’12 Subaru Impreza.

    • Lynelle says:

      OMG Greg. I bought a 2012 Impreza in May just three months ago and I have the same issue and am told the same thing. There is nothing wrong with the car. It is so annoying on long trips like you state because of the loss of power. To make it worse I bought a stick shift so when I lose power as I am shifting the car bucks back and forth for a second or two. That is even more annoying. Glad to see I am not alone and I am definitely going to pursue this further seeing that someone else is having the same issue.

      • brad says:

        I have the SAME problem in my 2012 Impreza, and was told it was normal. It is really annoying. Now that it is getting colder, and I have to use the heat, I notice the SAME thing (which I dont understand since I’m not using the AC)That loud air wooshing sound and loss of power is the worst!

  29. Justin says:

    2002 WRX, my a/c has been dead for the past 3 years, after some engine work was done. I finally decided to try to fix it, and it had a leak on the compressor output, replace the o-ring and it seems the leak is fixed. I hooked it up to a vacuum for 15 minutes and it held a vacuum for another 10. So I charged it on the low port to 30psi, turned it on and the compressor engages, but no cold air, and a hissing sound from in the cabin behind the dash while in use only. The high port only measures 90psi in use, and the low port 0psi while in use.

    Is the compressor shot from sitting without use too long? I read that the pressures should be…

    Low pressure: 18-28psi.
    High Pressure: 213-242psi.

    • Justin Stobb says:

      Might have a faulty Expansion valve but it could still have a low charge as well, the hissing sound may be pointing to air in the system as a result of the low charge.

      Also the 2003 has a known issue with the thermosensor in the Evap core.

      Justin

  30. Dustin says:

    HI Jason,

    The Subaru dealership wants $453 to replace A/C High Side Line and the O-Rings and adding Freon.
    I was wanting to replace it myself. Is there a forum or a video already on this that you could direct me to that would explain in detail how to replace the A/C High Side, O-Rings, and adding Freon? I’ve found a website that explains adding the Freon. Do I need to evacuate the air and moisture from the system before adding Freon? How does one do that?
    I have a 2002 H6 Subaru Outback.

    • Justin Stobb says:

      Hi Dustin,

      I cant direct you to any such forum or post.

      I will tell you it would be a mistake to only replace one hose however, you will end up with a leak sooner rather than later from the other one unless its already been done. Every time we have done one the other has leaked within a year.

      MSRP in our area for both hoses including the O-rings is $389.94 IF you add $25.00 or so for the R134A you will still be ahead if you are capable of making the repairs your self.

      You dont really want to Vent whats left in your system into the Atmosphere. You do need to evacuate the system after the repairs to remove moisture prior to adding the Gas.

      Hope that helps.

      Justin

  31. Dustin says:

    sorry…Justin. : ) Not Jason.

  32. Ed Daszewski says:

    Dear Justin,

    I have an ’04 Outback (2.4)..I have intermittant (25% of the time) interruption of cooling…especially in stop/go traffic (on Long Island Expressway, e.g.). The compressor quits and then comes back on a few minutes later. Seems if I maually turn off AC button when this happens, and wait a few minutes..then push it on, all’s well…until it quits again…often several minutes later.

    I’ve been told it could be a sensor. My mechanic friend pointed to a wired part at the top of what I believe is the receiver-dryer (cannister under hood just in front of PAX firewall). If this is likely culprit, must system be discharged to replace it? What do you think?

    Thanks for great site,

    Ed

    • Justin Stobb says:

      There is a switch in the Receiver Dryer, yes the system has to empty to replace the switch. I don’t think that’s going to be your issue how ever unless someone has confirmed bypassing the pressure switch will resolve it.

      I would suspect a higher than normal compressor clutch gap which can be measured and compared to a range of values, as well as testing for power to the Compressor Clutch when its acting up.

      Hope that helps

      Justin

      • Ed Daszewski says:

        Justin,

        Thanks for the tip. My co-worker’s husband is another mechanic (more my age of 66) who saw your tip just now and said I could try direct to clutch power connection and feel if the wire (assuming sufficient guage) gets hot….if so, that’s hi draw and something’s bad. Agree?

        • Justin Stobb says:

          IT would be better to test for power, than to supply power and take the chance of melting wires.

          Justin

          • Ed Daszewski says:

            Justin,

            Indeed. Okay, here’s the latest: drove home from work w/AC on (AC push button on dash lit) ….after 25 minutes of highway driving…(last 15 minutes in stop/go), cooling stopped….fans at radiator remained on….push button AC still lit…..drove the rest of the way home (25 minutes mostly highway speed) in same mode….no change, no cooling..pulled into driveway…left engine and AC on….inpected under hood…clutch disengaged but fans spinning….pushed AC switch on dash off…waited a second and pushed on….no change Then I pushed AC switch off and waited about 15-20 seconds….pushed back on…voila! clutch engaged….cooling again. Any additional suggestions? (This car has 182K mostly highway miles and is THE BEST)

            Thanks for your help!

            Ed

          • Justin Stobb says:

            Only suggestion is that when it act up it needs to be tested to figure out whats wrong.

            Could be clutch gap, AC relay, one of many switch’s, expansion valve, thermosensor etc.

            Justin

  33. Ed Daszewski says:

    Dear Justin,

    Forgot to mention…re. my ’04 Subaru, system is fully charged…normal pressures…no leaks.

  34. Bill Hale says:

    Justin,

    Great to see someone with knowledge and a great attitude.

    2003 Legacy Outback 130K miles.

    AC hoses replaced due to leakage you described. Pressures
    OK, 35 degrees exit air, leaves cleaned out of air supply.

    Blows cold, but thermostat shuts it off and it blows hot.
    Takes a long time to cycle to cold again and the evaporator never gets really cold.

    If I hook up compressor clutch to 12v and drive it, blower on high, it gets nice and cool.

    So I’m guessing the thermosensor is at fault, tho I understand that it could be frosting over. Don’t think
    so with the outlet air so hot.

    How big a deal is it to replace this on this model?

    Thanks, Bill Hale Loveland CO

    • Justin Stobb says:

      The Evap core needs to come out after recovering the R134A. This involves dash work as it comes out from inside the car. I would also replace the Expansion valve why you are there.

      Justin

      • Bill Hale says:

        Justin 2003 Subaru 132K miles
        AC cuts off… thought it might be too much R134
        and the pressure was a bit high — 340# @ 105 degrees: static is about 105# @ 90F. It blows
        cool when it runs. When I jump the compressor
        directly to 12v, it nearly freezes me out. It’s
        NOT the pressure over protection that is at fault.

        What is making it shut down?

        There must be a cutoff based on engine temperature! I finally noticed that when the coolant temp gets above the 3/4 mark–even a little bit–the command to the compressor goes away! And when it’s back above that mark, it
        cools again.

        The coolant temp seems unstable… usually around 2/4 but when it’s hot hovers above and below the 3/4 mark. And it doesn’t correlate much to what’s going on: ie, if the fan comes on, it doesn’t drop. Sometimes it’s highest when just cruising along at 50 mph or so.

        Water pump replaced when the timing belt was
        replaced at 125K miles.

        Relieved to figure out that it’s not the AC at all! But what to investigate first?

        Thanks, Bill Hale

        • Justin Stobb says:

          The coolant temperature is way to high if its hitting 3/4 on the gauge if you have owned the car for any length of time you have grown to observe the gauge typically goes a little less than 1/2 way and stays there unto you shut it down.

          Maybe read my head gasket article?

          Justin

  35. Caitlin wood says:

    Hi! I have a 2007 forester. I just got a new alternator. Brake light and battery light came on and mechanic said my charge was at 12?. Anyway, I got the car back today and it stalled twice. I then noticed it is not blowing cold air when the car is idle or in park. It is freezing when the car is moving. The car also feels like it is not getting full power. Any thoughts? Thanks!

    • Justin Stobb says:

      Hello Caitlin,

      The 2005 and newer models require a “Memory Tender” to be installed to the OBD port to avoid losing saved data. If this is not done it can stall and exhibit other symptoms whenever the battery is disconnected.

      I can only assume that step was not performed and you may have a vehicle perform erratic until its learned some new data points.

      Justin

  36. Morgan says:

    I have a 2005 4 banger outback, original owner, baby it. A/C doesn’t blow as cold as it used to, never had the A/C system serviced. I know where the low side ac port is, would it be dangerous to add 134a by myself with an over the counter product w/gauge?

    • Justin Stobb says:

      Hi Morgan,

      You can give that a shot your self, however it is a good idea every few years to remove the R134a, pull the system into vacuum , add fresh oil and refrigerant.

      If this is done the Ac compressor will most likely last the life of the car. I would at a minimum add some oil as well as refrigerant.

      Justin

  37. Ann says:

    I have a 2009 Forester. The ac is fully charged and I can hear the ac cycling on and off. No cool air is coming out of the vents.

  38. Jesse Peck says:

    Justin,

    Was reading many of these posts and some are similar to mine, but most were not exactly the same. (maybe I just got tired of reading).

    I have a 1996 Subaru Outback 2.2, When idling and driving under 40 mph the AC is warm even Hot, when i reach 45-50 mph it starts getting cold. But is never very cold at all.

    While idling my compressor only kicks on between 3-5 seconds every minute or so. Sometimes only once every 5-10 minutes.

    I tried adding Freon but it didn’t seem to fill unless the compressor was running. I think I only got like 6oz in. Also the pressure gauge on the freon doesn’t seem to be working unless the compressor is running.

    Some people are telling me I just need more freon in there so the compressor can run, is this true or do I have bigger problems with my compressor or other???

    Thanks,

    • Justin Stobb says:

      Hi Jesse,

      What you are feeling is just cooler ambient air because the car is moving, your Ac most likely does not function.

      The system is going to require much more than 6 ounces to make it work if its empty, and most likely you have a leak that needs to be looked into.

      One of the problems you will run into trying to service your Ac system, is that it is a system, with all sorts of possibilities, most of the time if your freezer quit working you wouldn’t tackle it your self with out knowledge of the system and the proper tooling.

      If the system is so low it blows warm, it most likely was empty, if it was empty is has a leak, if it has a leak you may need test equipment to find it after you fill it.

      Justin

  39. Terry says:

    Hello Justin,

    I have a minor issue with a 1998 Subaru Legacy GT limited. The green A/C button is difficult to depress when turning on the A/C. Likewise, when turning it off it sometimes take over 1 minute for the button to pop back out after being depressed. Can some kind of electrical spray resolve this or is the problem deeper than that? The A/C does work fine, but I am concerned that someday the button may simply stay stuck in one position (on or off).

    Terry

    • Justin Stobb says:

      Hello Terry,

      This is actually very common.

      Over time, pop and coffee have spilled from the cup holder into the Climate Control mode selector.

      I would suggest a spray can type glass cleaner like you can purchase at Costco, then spray it on the mode selector and let it sit for a while, it should emulsify some of the residue and free up the button as well as the others. Don’t use Windex or another plastic bottle type cleaner, only something dispensed from aerosol type can will suffice.

      Hope that Helps

      Justin

  40. Hello Justin says:

    I have a 2005 XT and have had poor AC performance consistently since the car was new. Dealer never found any issue (they just used an IR thermometer in the vent and said it was fine!) even after I dealt with the main office.

    I had my mechanic try his hand it it and he evacuated the system and recharged (just be be sure it was filled to spec) but it didn’t help.

    The deal is this….the AC cycles frequently. I would say it blows pretty cold and feels stronger for about 5 seconds then the compressor seems to cycle off-when it does the air quickly gets noticeably warmer till….about 15 seconds later when it starts over.

    The problem is that even in moderate weather…the car just doesn’t cool down well….in this heat it I just point the vents at me and deal with it…

    I kind of got frustrated and stopped following up on the problem (yes…for a long time!) and I have lived with it but I decided to take another stab at it. in your experience, should I expect better performance than that or is this type of noticeable cycling and temperature change normal?

    Thanks

    • Justin Stobb says:

      Hi,

      We also own a 2005 Outback XT, and have no complaints with the AC.

      Not sure whats the issue, only to say its very serviceable. With out temp, pressure and voltage readings there is little I can offer on your exact situation.

      You will need however to seek out a Subaru Expert, or at the very least a competent Technician capable of diagnosing your issue, and willing to invest the time needed to do so.

      What happens is whenever there is an issue such as yours the “market place” does not allow for a proper diagnoses, especially at a Dealership and compounded further if under warranty.

      Sorry I cant offer more

      Justin

      • Hello Justin says:

        Any chance you could help steer me to someone…(I know that is a long shot….on the other side of the country!) in Northern NJ.

  41. Cambra says:

    Hello Justin,
    I have a 2008 Subaru impreza outback sport. Recently I noticed when first turning on and off the defrost I am hearing a “rattling” noise. Seems to be working fine otherwise. My a/c however was just recently used with a heat wave and is making the same noise and blowing warm area. I plan to take it to mechanic this weekend to have a/c tune-up and pressure test. Wondering if you have heard of any similar sound associated with a/c not working. Hoping it is a minor issue. Thank you in advance for your time!

  42. Ron says:

    Justin,
    Read all the posts. Lot’s of good advice here. I have a problem with the A/C on my 2002 Outback H6. I live in Florida and the A/C is an essential component. It sometimes blows cold and sometimes doesn’t. Generally will never start up in the morning first thing. Clutch will not engage the compressor. After shut down and restarting the engine it may or may not start up the compressor next time. No rhyme or reason. It may be the 6th time during the day when it will eventually start and blow cold. After the first time it engages, it will engage and blow cold the rest of the day. After leaving it overnight the problem returns. I think it’s electrical since it blows cold. Took it to my repairman who several years ago replaced the ‘O’ rings and fixed me up when I had a problem with it leaking. Explained it to him. He diagnosed it as a bad sensor that kicks out the compressor when the compressor locks up and that there is a TSB out on it. He ordered the part and replaced it. Did not fix the problem. He admitted his meter was faulty when he diagnosed the problem initially and both parts ohm’ed good (old and new) He says it will take some time to rediagnose it. I decided the climate control unit was bad since eventually it does work although it seems to be getting worse and taking more restarts to engage. I replaced it. Same problem. Any ideas. I know it’s tough to diagnose problems like this online but you seem pretty good at it. Thanks in advance, Ron

    • Justin Stobb says:

      Only thing that will actually get to the bottom of it is to be testing for signal loss when it acts up.

      Could be a relay, but could be something else as well.

      Justin

  43. Jerry says:

    Hey Justin,

    I have a 2004 Outback LL Bean with a leak in at least one of my hoses but am making a trip soon so in the mean time I’m trying to throw some 134a in there but having trouble finding the Low Pressure port. Could you describe or send a link of a picture so i can fill it up.

    Thanks

  44. Eric says:

    Hi Justin,
    I read through all of the posts and saw one that was similar to mine (Amanda’s), but unfortunately it went unanswered so I figured I’d ask again.

    I have an ’09 Legacy and over the past 2 or 3 weeks I started noticing the A/C was becoming less and less effective (to the point where it really got to blowing cold when the engine was revving pretty high. Late last night it eventually gave out, and today it is still not blowing cold. I don’t think I can hear the compressor running (when I push the A/C button there’s no noticeable change in sound).

    I was thinking today and remember about 3 weeks ago I was on a long road trip and took what amounted to a small “Dukes of Hazzards” style jump over a road crossing that appeared to be missing a stop sign. This resulted in a plastic cover on undercarriage to partially come off (it’s still on, but only being held on by the plugs on the front of it). Does that cover protect the A/C unit? Is it possible that our inadvertent shenanigans punctured the condenser?

    Also, there have been some minor electrical issues recently (keyless entry not working all of the time, windows not rolling up or down until the car is restarted)…not sure if it’s possible that the A/C button is just on the fritz.

    Thanks for your help.

    • Justin Stobb says:

      Hi Eric,

      Its possible something happened when jumping the car but I just don’t have anyway of knowing, AC is a system with many possibilities and its just not plausible to be able to know each situation.

      Gauge readings will indicate low pressure, which could be from a low charge and would support that theory, but without gauge readings I am just guessing.

      Justin

  45. Robert Jack says:

    I just bought an 04 subaru outback. Immediately the ac didn’t work. THey charged it with freeon.Then it would work for about 5 min then blow warm air. I have taken it back 2 times since (a total of 3 times now). and each time they tell me it’s fixed and it is not.

    THey have ran a diagnostic and everything checks out. THey said something was leaking and replaced it, and it is still having the same issue. These guys are friends of the family for over 30 years. But I feel they are either unable to tell what is wrong or they DO know what is wrong and realize it will be expensive.

    TEchnically it is still under warantee so they have not been charging me. But I just want my ac fixed.

    It runs fine when it is cold out. When it gets over 80 it only runs for about 5-10 min then it is hot air (or outside temp air) coming through.

    Of course mechanics get pissy if you make suggestions, but I almost want to forward this url to them.

  46. Steve says:

    Justin
    I own a 2006 Baja this summer ac has been earatic in performance. did a DIY recharge system was low but minimal. but still have problem. One symptom is a clicking or popping under the dash. When not clicking system works OK. When clicking starts system blows warm air. I was affraid I had overcharged but a friend who has access to a guage set said it is ok. When popping occurs at low speed or RPM I hear a groaning which I assume is the clutch slipping on the pump. Dont notice it at highway speed. Thought maybe cabin filter was extra dirty but even with removed still does same thing. I believe I am up for an expensive fix. Got any sugestions

    • Justin Stobb says:

      The Ac relay is under the Hood, so I dont think the clicking you are hearing is from that, maybe the Expansion valve is sticky?

      Gauge readings when its acting up plus possible signal loss is whats needed to know next.

      Justin

  47. Hubert says:

    The AC in my 2006 Outback (4cylinder) operates erratically. It does not cool when the car is stopped but picks up when the car is moving.
    I took it to the dealer who has been trouble shooting. The work so far has cost $750 (included replacement of the expansion valve — they said pressure differential readings led them to think this was needed). This has not fixed the problem so troubleshooting continues. The dealer mechanics say there is some foreign material in the system and the next step is taking apart all of the lines to see if they can locate the source and determine where there might be blockages. This next investigation step is estimated to cost another $350 or so. It is likely some other components will need to be changed out deppending upon what they find, so I am figuring that we will possibly face charges pushing $1200 — $1500 — $2000 — who knows how much.
    I am concerned that I am being taken for a ride here.
    So the questions are these: is there a standard Subaru trouble shooting procedure for these systems? I have asked the mechanics why they have not been able to examine the expansion valve to see from that what the foreign material might be…why rip the system apart further to determine what might be causing blockage — are these not reasonable questions to ask the dealer? I know this is complex — that the number of possible problems is large –but does what I am describing sound within the bounds of reason? Or, should I have them button the AC system up and take it to a mechanic that specializes in AC repair?

    • Justin Stobb says:

      Hello Hubert,

      Most Ac issues are straight forward, but sometimes they are not. When faced with a challenge its frustrating for both parties.

      Dont see a lot of Debris or Expansion valve issues, but Debris would ruin even a new Valve so its possible.

      The expansion valve has to be removed to inspect and even then would have to be cut apart to look for any debris.

      Justin

      • Hubert says:

        Thanks, Justin, for your response. It turns out the the final fix, after a significant discount, was nearly $1600.00 (about $520 on parts/$960 on labor). It turned out that there was some kind of obstruction in the receiver/drier.

        The work included, after replacement of the expansion valve that I mentioned last time, disassembly of all lines and components to find the obstruction. It turned out to be a problem with the receiver/drier. As this is rigidly attached to the condenser, the whole assembly had to be replaced. Because it is a sealed component/assembly, the mechanics could not determine what the obstruction was without cutting it apart.

        I would not ask that you spend any more time on this, but, fyi, I have two questions for the dealer and Subaru: 1) design of the component: why did the drier fail in this sealed system? (the drier has a desiccant in it….and I question how it is expected to last lifetime of the car without becoming saturated); and 2) why does the condenser/drier assembly cost $366 when a KOYO Cooling aftermarket condenser/drier assembly costs $122 (a Kool Vue replacement costs even less….$64.63)?

        I question, in general, Subaru’s AC design/reliability. I know they went to a smaller system in the Outback starting in 2005. Also, I will think hard in the future about whether taking the car to the dealer for issues like this is the way to go (rather than bring it to a reputable, independent mechanic).

        Thanks.

        • Justin Stobb says:

          Hi Hubert,

          The repair you have had to make is not common, the receiver dryer is not a lifetime component by any means its just not popular to tell drivers this.

          As far as pricing anything and everything sold to you by Subaru will have many layers of mark up on it, you will always be able to find a cheaper price on any component available in the aftermarket especially a crash related component like a condenser.

          I don’t like the dealer for repairs, this is because I have an understanding of how things work at a dealership it does not benefit the consumer.

          Justin

  48. Tony says:

    Justin

    I have a 2011 Outback 2.5i Premium. The problem is the A/C at idle. I have not taken it in to the dealer yet, wanted to do my homework first.

    The A/C delivers cold air immediately when starting an engine cool enough to trigger the default cold start high engine idle, ~ 1500-1600 rpm.

    The A/C will not deliver cool air upon starting, if the engine has been recently driven (warm engine idle speed ~ 600-700 rpm), until the car has been driven a while. How well the car cools, depends, of course, on the outside temperature, speed achieved and how quickly. The A/C functions very well with the car moving.

    When the car is not moving and the engine is idling, having cool air flow from the A/C vents is unpredictable; sometimes, sometimes not. The following occurs randomly:
    Engine will idle at normal engine idle rpm and there is no cool air flow
    or
    Engine will intermittently rev up and down to maintain a flow of cool air
    or
    Engine rpm will flick up and down very quickly, ~ 1sec, with no A/C output

    Tony Johnson

    • Justin Stobb says:

      The Engine is commanded by the ECM to increase Idle speed when the Ac compressor is engaging to prevent stalling due to increased load.

      You cant really correlate a 1 sec blip in Idle speed with air temperature.

      If I had to guess I would say a car wash took out a ambient Temperature sensor.

      Justin

  49. Rick says:

    Hello. Lots of great information on this discussion site. I am the owner of a 1992 Subaru SVX. On hot days, the a/c works fine and blows cool air for about half an hour, then it just blows warm air. After stopping the car for a while, that will fix the problem temporarily, but after 5-15 minutes or so the a/c will only blow warm air again.

    Because its extremely hot now, I thought maybe the car was getting too hot and the a/c was shutting off automatically. I got the radiator flushed and put in new coolant, but this hasn’t affected by a/c problem at all.

    Any ideas Justin?

    • Justin Stobb says:

      Hi Rick,

      There are so many possibilities its just tough to through out guesses.

      It could still have either a cooling system issue or electrical issue with in the AC, climate controls, or mechanical issue with the Ac such as the Expansion valve.

      The place to start is gauge readings of the high and low side pressures.

      Justin

  50. Richard says:

    I have a 2007 Subura Legacy wagon, I noticed this week the A/C at first worked intermittenly, and then today did not work at all. Additionally, the temp / radio display can flicker off during the initial start up of the car. Could I have an electrical problem?

    • Justin Stobb says:

      Its possible you have 2 separate issues, one may just be a weak battery? The other a low Ac charge brought on a by a leak?

      • Richard says:

        the battery was replaced this past winter. I will have the ac re-charged. thanks (it seemed unusual that the ac will run for 10 – 15 minutes after starting the car, then no cold air)

  51. Emil says:

    Justin,

    Great forum posts. I appreciate them. I have a 2003 Subaru Outback H6 LL Bean edition. A/C problems. I couldn’t diagnose it, so I took it to the local Subaru dealer. They said it needed a compressor and speed sensor (in the rear of the compressor). So I bought the speed sensor from them and installed it. Didn’t resolve it. I bought a remanufactured compressor, with a speed sensor installed, and that seemed to work for a while, but problem eventually came back again. In both cases, I evacuated the system, vacuum checked for leaks, and recharged with exactly the right amount of R-134a – 23 oz. checked hi/lo pressure at 1500 rpm – 28psi lo, 245psi hi.

    The new compressor worked great, but only about 90% of the time. When it didn’t work, I could cut the car off, start back up again, and that usually resolved it. A couple days ago, it was really hot – 100 deg. in North Carolina, and while driving down to South Carolina, I couldn’t get the A/C to stay on. I cut the car off about 20 times, but it would run for about 3 minutes and then blow hot again. When it blows cold, it blows ice cold. While reading through forums, it seemed like the issue might be the climate control module. I pulled it to inspect it, and the hose connecting under the dash. After reinstalling it, I noticed that the sensor behind the little circle grille in the front of it, which is in the flow of the air which routes below the dash, was covered with dog hair and dust, from previous owner. I cleaned It off with a pick, and the A/C hasn’t turned on since. Do you think I may need to replace the climate control module? Is the sensor in the front of the module a thermosensor? Thanks.

    • Justin Stobb says:

      If you used an Aftermarket Ac compressor that’s most likely the issue.

      It needs to be tested. that way when it fails to work you know the following.

      Does the Ac compressor clutch have a signal to it and fails to engage or does it not have a signal to it and if not where is the signal loss stemming from. With out those answers you are just tossing more money at the potentially wrong repairs. I know that most aftermarket Ac compressors for the 2001 to 2004 H6 will not have the updated speed sensor.

      Justin

  52. Tad says:

    Hey Justin,

    I have a 2004 Impreza Outback Sport, you guys replaced the head gaskets and timing belt last november and it’s been running great! About a week ago though, the A/C started to have a strange smell to it, kind of sour and almost “fishy”, as a co-worker of mine described it. Occasional it will also blow out a white mist, usually only when the weather is warmer. Otherwise though, it still works – A/C is cold and heater is hot. I’ve been keeping it off and just cruising with the windows down, while looking online for a DIY solution. I haven’t been able to find anything though, and it sounds like A/C fixes might be a little tricky for DIY anyway.

    Any ideas what might be causing the smell/mist?

    • Justin Stobb says:

      Hi Tad,

      That sounds like a Evap core leak if you are getting a fishy smell in the car, dont use the ac until you can have it looked at, the gas is harmful to you.

      Justin

  53. Murlan Kaufman says:

    While servicing my AC in my 2002 Outback I found that the heater core is not shut off completly by the mix door, resulting in about 10 degrees higher air conditioned outlet temperature. Is there a cable adjustment that will completely close the mix door? Or is there something not working properly with the mix door?

    I get good cooling normally, and this may have been the way the car was when we purchased it new. However, cooling would be improved if the extra heat from the heater core was not mixed in during really hot summer weather.

  54. Noah says:

    Justin,
    My wife just had her 2005 subaru forester xs in the dealership due to AC problems. It was not blowing cold, just warm air. It was sporatic from time to time that it might try to blow cold. The compressor would spin one time around and then stop for about 5 seconds and then spin once again. this happened over and over when she had the carr in park and the AC on. While driving, if she turned it on, it would “lurch” and not be smooth. The dealer added dye to try and find a leak. They also said that the pulley was bad and replaced that. She had 1200 dollars worth of work done. Now 2 days later, the cars AC compressor supposedly seized and caught fire and melted some plastic under the hood. the dealer now says it was the compressor that was bad and thhat there is no way of telling it was going bad. They want to charge her another 1000 to replace the compressor. They have given her a dealer car to drive and have said that they have knocked off 200 dollars the replacement and will only charge her for one hour or work. Were they in the wrong? Should they have been able to tell if the compressor was going bad? I thought it was just due to the way it would spin, seize, and spin.

    • Justin Stobb says:

      Noah,

      When you say she had $1200.00 work done, do you mean in total to the car, or just servicing the Ac the initial visit?

      If it had a 90 k service and front brakes replaced it has no bearing on the fact the AC stopped working.

      We do not see a lot of Ac compressor issues, but it can happen, especially if it had a low charge due to a leak, thus not enough oil to lubricate the compressor.

      Hope that helps

      Justin

  55. Don says:

    Justin
    Just bought a 98 legacy outback 2.5
    The refridgerant was empty, put new seals on pump.
    Evacuated at 29 psi. for 20 min.
    As you add 134 the compressor gets noisy,
    pressures are low 50 high 150
    With more 134…low 70 high 200
    Sucktion and discharge lines warm to hot
    So I tried a used pump and same thing.
    Is there any thing else i need to check before
    I look for a pump at the auto parts store
    I use Napa and O- riely.
    Could it be something else…Dryer,Orfice valve???
    My old haynes AC manual talks about EPR valve, STV/POA
    valve. What do i have?
    New pump is expensive want to make sure its not something else.
    Thanks for any feed back.
    Don

    • Justin Stobb says:

      Did you add any oil?

      Could be many things, with out seeing it I would just be guessing, and that’s just going to cost you money. The low side pressure of 50lbs with the compressor running is actually to high. When the compressor is off the should be close to equal.

      I would think twice about using anything for the two parts stores you mentioned on your Subaru unless out of a bottle, its quite possible the compressor is defective.

      Justin

  56. Don says:

    So replaced the expantion valve and filter dryer
    Blows cold.

  57. Johnny B says:

    Hello,

    Overheating and AC problems. I have a 2002 Outback H6 with 144,000 miles on it. I drove the car around about 10 miles yesterday on surface streets and the freeway here in Los Angeles. For the first three miles or so i had the AC on the whole time and It was working fine, very cold… and i also had NO vehicle overheating issues yet. I then went to lunch and the car sat for about an hour and a half. When i got back into the car and drove off i turned on the AC i noticed it wasnt getting cold and the air smelled a litle old and musty. I was shocked because it was working fine when I parked the car. So i kept the AC off and rolled the windows down a bit to keep cool. I then drove about another 4 miles on the freeway going maybe 50 MPH or so then to the surface streets again…then all of a sudden the car died at a traffic light. I restarted the car in a bit of confusion and anxiety because I was in the lovely and ever so quickly moving LA traffic. Plus the vehicle engine was running so smooth I was perplexed at what had caused it to die all of a sudden. I then glanced at the temperature gauge and almost blew a head gasket myself when I noticed the needle was pegged all the way HOT. The car must have overheated in the last 4 miles because I always continuously check my gauges n things while driving. I pulled over and let the car cool down for an hour or so. When I looked under the car for any water leaks to explain my overheating issue I noticed what appeared to be and was about 3 ounces or so of oil from the AC system. It had leaked out all over the ground. I then determined that my radiator was about one and a half gallons of water/antifreeze low. I added this in water and drove home with no problem. Although upon parking and looking under the car again I noticed water/coolant leaking all over the ground. The next day I found the culprit of the engine overheating issue was a leak/hole in the lower radiator hose. I replaced the hose and flushed the engine with clean water and refilled it with fresh water/antifreeze mixture. The car runs great now and doesn’t overheat. I got lucky I didn’t blow a head gasket. The AC appears to run fine and quiet but it is definately not cold anymore. When I overheated the engine I am assuming I overheated the AC compressor or system as well even though it was off. After reading many of the previous posts my plan of attack for the AC system is to replace the O rings on the high and low side hoses as they meet the compressor. As well as check for any oily residue on the hoses themselves and the crimped areas to determine if a oil/134a freon leak occurred there. Any other suggestions or theories of what to do or why both overheating and AC problems occurred at the same time? Thanx in advance :-)

  58. Jules Zan says:

    Hello,

    I have a 2001 Forester. The AC clutch stays engaged at all times, even with ignition off and key removed, so I’m assuming that something is shorted to cause a constant 12v current to the compressor. However, it ONLY drains the battery when the system is charged. Burnt out pressure switch? I already tried changing out the relay, but the clutch does not disengage even with the relay removed. It does disengage when I unplug the compressor itself. How can I determine what is causing the battery drain? Thank you.

  59. tyson says:

    I have an 04 wrx, the low side hose was leaking so I replaced it and had it recharged. now i have 12v at the compressor at all times. no matter what the setting is on its engaged, freezes up after 40 mins of driving. so I just unplug the wire to let it defrost. I check fuse, and relay under hood and there is a jumper underneath the relay that jumps 12v to the compressor? I don’t know if it’s supposed to be there? I pulled the jumper out and bought a new relay and it didn’t help just no power to the compressor whiteout that jumper in there. im lost, cause it works great before it starts to freeze up

    • tyson says:

      found that I’m not getting the ground signal to the relay to lock in the relay. jumper is not supposed to be there , so took it out

  60. Jules Zan says:

    Hi Justin,

    Thanks for this great forum. I’ve got a 2001 Forester that has the A/C clutch engaged all the time, even with the car off and key out of the ignition. It stays engaged like this until I pull the connector. A/C itself works fine, but there is an obvious electrical issue.

    The clutch being engaged pulls a slow drain on the battery even with the A/C system evacuated, but with the system charged (i.e. full pressure), there is an immediate and complete battery drain.

    I pulled the pressure switch thinking this was the problem and the clutch stays engaged, changed out the A/C relay and it stays engaged. My non-specialized mechanic said it was the control unit shorting out the system, so I replaced that. No change. The only way to disengage the clutch and save my battery is by pulling the compressor connection itself.

    I’m no mechanic, but I’ve gathered that the clutch is getting a 12v charge at all times, which is why it is staying engaged, but any thoughts as to where this short might be coming from if it is not the relay, pressure switch or control unit?

    Thank you!

    • Justin Stobb says:

      Hello Jules,

      Not without looking at it, sorry. That’s not something I can arm chair diagnose.

      If I had to guess I would say the coil in the Clutch has shorted to ground. But you haven’t mentioned signal only parts changing and the assumption of signal at all times?

      I would start with verifying the presence of voltage at the connector to the Ac compressor at all times and then trace down the cause of it proves to be true.

      Justin

  61. Karen says:

    I took my car in to be looked at and was told that I need a new compressor. I’m saving up the money for it. My question is… now that it is getting cooler out, is it safe to run the heater with a bad compressor?

    • Justin Stobb says:

      Hello Karen,

      The Ac compressor should be disconnected electronically by either disconnecting the connector at the Compressor or removing the relay or the fuse.

      Justin

  62. josh petermann says:

    hi justin,
    im working on a 03 outback with a 2.5 manual trans. this is a customers car that i have a/c leaks on for a year+. original issue was the high pressure hose blew, replaced hose, performed evac and recharge. came back, discovered leak at accumulator and condenser, replace all o-rings with oem. came back again still leaking installed new accumulator/dryer. back again, steel line at condenser still leaking and at both lines on the dryer. have u had this issue. i have even tried installing bigger o-rings. leaks out about a month after every repair? im thinking steel lines could be bad or defective dryer as well as condenser?

  63. Nic says:

    I am working on a 2005 subaru legacy i. The vehicle idles fine until I turn the AC on. When I do turn it on, the rpms drop every time the AC compressor kicks in. I was wondering why it might be doing this

  64. Custom Filters Air says:

    This site was… how do I say it? Relevant!! Finally I have found something which helped me.
    Appreciate it!

  65. Millie says:

    I own a 2005 Subaru XT Turbo and my problem with the car’s A/C is that it is making a LOUD noise. It works fine, but that noise is just so annoying. I took it to the dealer and they claim that I need a new blowing fan which is almost $300, but I don’t get it; there is nothing wrong with the air flow. Has anybody have this problem before, and how was it fixed? Thanks.

    • Justin Stobb says:

      Hi Millie,

      The bearing in the blower motor may be failing, or it the fan assembly it self may be full of debris?

      It wont work forever making noise.

      Without hearing the noise no one can guide you. $300.00 really isn’t that much money to spend on a 8 year old car.

      Justin

  66. Robin says:

    Hi there — I have a 2004 Outback. The issue I’ve had for a couple of years is: after about 20 minutes of highway driving, no air comes out of the vents. This happens in the summer with the A/C, and in the winter with the heat. I can hear air blowing, but nothing comes out of the vents (it’s as if a door shut somewhere inside the climate control system). If I turn off the system for a while (sometimes for as little as 10 minutes) it will come back on (cool or warm air starts to leak out the vents), or if I stop the car for a while, when I turn it back on, air comes out of the vents.

    I gather that because it takes about 20 minutes of solid highway driving for the issue to manifest, no mechanic I’ve taken it to has been able to replicate it, let alone fix it. Which is why several years later I’m still driving around with the problem.

    Thoughts on what it could be?

  67. Andrea B says:

    Hello. I have a 2008 Subaru Exiga with the right hand side of the AC blowing hot air and the left hand side blowing cold air. I was informed that the O-ring needed to be changed and so it was changed and re-gassed. a few weeks passed and it is back to blowing hot air on the right and cold air on the left.
    what could possibly be the cause and how can it be repaired? is there a possibility that the core needs to be changed?
    May I also add that I really like the info on this site

  68. Sheerah says:

    I really love your article above. I recently purchased a 1995 Subaru Legacy. The car is in pretty good condition but the AC really isn’t working. My husband and I work in HVAC so we know our way around compressors, but the compressor and the coil are operating just fine, and it is charged with 134A, it only seems to work when we jump out the relay. When the relay isn’t jumped out the relay turns on and off about every 20-30 seconds. We’re not particularly knowledgeable about car air conditioning so we were considering replacing the relay. Is that a good idea or is there another part we should be looking at that we are not aware of?

    • Justin Stobb says:

      It could be the relay, or the switch or something commanding off the AC.

      This is where a scanner capable of data helps as you can see Ac request in the Data stream and also if the computer thinks the Ac is on or off.

      Have you verified signal from the switch to the relay?

      Justin

  69. Blair says:

    I have a 2005 Subaru Legacy 3.0R. Brilliant car however I have just noticed that when I turn the demister on the air blows warm? Everything else seems fine, I just can’t get the demister to blow cold? Why would this be?

    • Justin Stobb says:

      Demister?

      If you are letting me know that the air in “any setting” is hot only than there could be an issue with the climate control system that needs to be looked into.

      Justin

  70. Kevin says:

    Hi,

    I have a 2010 Outback 2.5 Premium. I noticed recently that the cabin wasn’t getting as cool as it was in the past, and realized that the two left dash vents were blowing out air at a warmer temperature than the two right dash vents. The air on the left side isn’t hot or warm necessarily (maybe ambient temp), but the right side is noticeably cooler (more how AC on a max setting should feel). Any ideas what this might be?

    I should mention too that I have noticed a slight hissing sound coming from the left vents for some time whenever I have the AC running, and goes away when I turn the AC off. I never noticed this in other cars I have had, but thought it was just a whistling sound from air flow. Now I wonder if there is some kind of leak.

    Thanks!

  71. Rob says:

    Hey Justin,

    Great info here, so I was wondering if you had any thoughts on my issue before I go to the shop.

    My 2005 92X Aero (WRX in drag) currently has no AC blowing from the vents. There is no noticeable change in RPM to indicate that the compressor is engaging, yet even when the system is off (No AC on), I can hear a whistle from under the hood, at low RPM’s that get higher as the car accelerates.
    Any ideas?
    Thanks in advance

  72. Mark says:

    hi i have a 2006 legacy. i hear a rattling and a grumbling sound when the ac is on. when i turn the ac off, it continues for 1min and then stops. any help?

    • Justin Stobb says:

      Most likely either the tensioner pulley bearing is failing or the compressor clutch or compressor, without someone having a look its all just a guess.

      Justin

  73. Chris says:

    Hi Justin,

    I have a 2002 Impreza (2.5RS) and the A/C is no longer blowing cool air. The dealership has advised that my A/C pump needs to be replaced. I have looked at an OEM part catalog, and I wanted to confirm that the pump and compressor are the same part. Additionally, they have quoted me about $950+ tax for the service. Is this reasonable, and could this be a potential DIY job?

    Thanks!

    • Justin Stobb says:

      Hi Chris,

      By law the refrigerant is not supposed to be vented into the atmosphere. So if you have recovery and charge equipment than yes. If you dont than yes it could still be a DIY just know your breaking laws shops cant. You also need to be able to measure the oil going int the Compressor.

  74. AL says:

    Hi Justin,

    I have a 2001 WRX turbo. Using my AC gauges, I determined that I had no pressure in the system. I used a leak detector and found both connections on the compressor were leaking. This was probably caused by a repair that Subaru performed. I replaced both o-rings and I am waiting for my AC guy to re-charge the system using his vacuum pump. I am using Johnsons R-134a A/C Refrigerant – 12 oz cans. The shop manual says I need 17.6 oz. This refrigerant does not contain oil. How much oil should be added? The shop manual says “DH-PR”. I think that’s a mis-print.

    THANKS!

  75. Elyse says:

    Hi,
    I have a 2004 WRX I have a problem with my air conditioner intermittently blowing hot air. It does this when it is about 85 degrees and usually I am going at least 35 mph. I can here a loud thump every time it stops and restarts. I took it to the subaru dealer today and he said the high side pressure is getting over 400 when the gas is pressed, but to do a diagnostic he wants 90 dollars plus the cost of the repair. Is that charge normal? I am a broke collage kid and I really need an air conditioner in south Louisiana.

  76. Bill says:

    Hi Justin,

    I have a 2008 Subaru Legacy. Sometimes neither the a/c or the heating systems blow at all. Other times they will work fine. I just had my a/c belt changed within 30 days at dealership. I noticed this occurance about 2 days after the belt was changed. Any ideas or advice as to why it will work sometimes and not other times?

    • Justin Stobb says:

      Hi Bill,

      Its tough to correlate that from here. The blower motor is in the heater case in the car, and if there is no air flow it may be whats the matter.

      Justin

  77. Larry says:

    Hi Justin, I have a `02` Outback, llbean H6 the compressor clutch will not engage. Gauges show high pressure on high side of system. Fuses and relays are good, have power to the compressor. I just bought the car 6 months ago, in winter, so I have not tried to use the air until now. Any ideas I can try? Thanks for your help. Great forum!

  78. Adrienne says:

    I have a 2012 forester. I am having a problem with the drivers area warming up to the pint where I want to get out of the car. The weather outside ranges from 48 to 115 when this happens. Last time it happened, I drove maybe 1 block before the drivers area heated up. The temp outside was 61. No butt warmer on and no heat on. All temp dials were in the blue.
    Been to the dealership 2 times and they said I have to ride with the a/c on 24×7 and with the recycle button on all the time. After 10 yrs taking,exhanics, this doesn’t sound right.

    I am tired of these guys looking at me as if I’m stupid. Any comments??

    • Justin Stobb says:

      Hello Adrienne,

      Here is what you need to do. start with getting out the owners manual and make sure you are 100% familiar with all of the controls and functions, turning the system off does not mean hot air will cease to flow, its about where the setting was last.

      If after that we have determined there’s no way its not a lack of comprehension of the system we know there is a fault, you will need to go back and be firm , walk in with the owners manual, show them you have read it and explain its not working as designed.

      If after all of this your still not where you want to be the next call is into SOA to complain.

      I can not speak to the staff where you are taking it, and they should never look at you or treat you like your stupid, but having said that we deal with customers on a daily basis that fail to understand an aspect of their Subaru and do in fact take it out on us. Little things like accidentally putting the key less system into Valet mode by messing around with the buttons, hitting the parking light switch on the column, not understanding the climate control and recirculate functions etc. Its just not possible to know on the surface who your dealing with, someone who understands the car and has a real problem, or someone to lazy to break out the owners manual and have a look.

      For a car to be looked at and repaired under warranty Subaru just like every other car company wants to rule out driver error, once that’s been ruled out its up to you to apply the needed pressure to get it resolved, warranty situations can be frustrating for everyone.

      Hope that helps

      Justin

      • Adrienne says:

        Thanks for responding Justin
        Answers to your questions| yes, I have taken the manual out and read up because it was so hot in the drivers area. Yes I have called SOA and received a case number and a guy from SOA met me in Santa Monica, ca, yesterday.

        I met with the service manager and the SOA guy. The SOA guy listened to my issue and proceeded to get into the drivers side. He turned on the engine, then the fan. Ran the fan for a couple of minutes and then turned on the a/c. It cooled down as expected. He looked at the dials and then got out, saying its working as it was designed.
        the corporate guy sent me an email recapping my visit to the dealership. Told me if it happens again bring it in. Why, to feel stupid for a 3rd time? O boy.

        The problem is not the a/c. The drivers compartment heats up in any kind of weather, from 48 to 115 degrees outside. Each time, the drivers area was over the temp outside. 115 outside and inside it was coming out hotter with the a/c on and the recylce button on. It happened twice this wed at 330pm and at 7pm, weather outside was 71. I don’t need a/c at sunset . The compartment heated up so much, I almost stopped and got out. I was literally sweating. Happened last week in 55 degrees at 1030pm. I don’t need a/c at 1030pm. The drivers area will heat up whether I go 1/8 mile or 50 miles. It’s almost unbearable.

        As I was leaving, I told them I own several cars, not one has this issue. They just said well this is the way this was designed. I felt stupid, duhh don’t you understand your A/c? They told me to run the a/c all the time and with the recycle button on all the time.

        Question? Is it a safety issue to run recycled air, stale old air , all the time? I get really sleepy and have to roll down the window.

        On a side note, I have worked on cars for over 10 years. I know the basics and understand when im hearing a line of bull. My a/c is the basic model, the one with 3 dials. Nothing fancy.
        Any suggestions? been a loyal customer for over 8 yrs…

  79. Adrienne says:

    Hi Justin
    Thank you for responding. I have read the manual on the a/c and how to use. The only reason why I read was becuz I’m burning up.
    I have a case # from SOA. They sent some guy out to meet with me and discuss the problems. He sat in the drivers seat and turned on the ambient air and then the a/c. Of course he said it works fine. Got out of the car and that was the end of the technical part. This must be a new way the technicians are doing thing now.

    I don’t think it’s an a/c problem. I mean I am very warm sitting in the drivers seat in 55 degree weather. It was extremely hot in 115 degree weather too. It was hotter inside than outside. I don’t run the a/c in 48 to 70 degrees. I’ve had passengers in my car and they couldn’t believe how warm it was, as they sat in the passenger seat nice and cool.

    They wrote me back today and told me that the a/c is working fine and they can’t find the problem. “if it happens again, bring it in”.
    This is my second Subaru and I’d this continues, it will be my last. I gave my sister my 2005 at 45k and all of the sudden she needed a new head gasket. Wrong!

    Just so you know, I have worked on cars for over 10 yrs. I do understand the basics and understand when I feel stupid walking away, as if I don’t know what I’m talking about. I’m sorry to blow, but I need some help and this was the only place I found who was addressing a/c.
    Running a/c 24×7 doesnt sound right and recycled air on all the time?

    • Adrienne says:

      One other thing, the climate control is not the dual auto climate. I have the 3 dials, 1st one on left is where you want to direct the air, 2nd dial is the fan speed and the 3rd is the temp, blue means cold and red means hot…

      The did say its working as it was designed

  80. Adrienne says:

    Hi Justin
    I’ve sent you 2 replies and do not see them anywhere.
    In regards to the owners manual, yes I have read and do understand how the a/c works. In regards to SOA, already have a case # and they sent there representative out on Thursday to meet and discuss issues.

    I want to make my issue crystal clear. This is not an a/c problem. The problem is, the drivers compartment heats up to VERY warm when the a/c is not on and the temperature outside is 48 to 66. All the dials are in the blue and the fan is off. It gets so warm in the drivers compartment I have no choice to open all the windows and sunroof.

    In aug 2012, I was in 115 degree weather. The a/c was on and the air coming out of vents was cool. The drivers compartment area, as so warm, I had to pull over.

    June 19 2013, the temp outside was 71, a/c was not on. I drove 3 miles and by mile 2, the drivers compartment was so hot, I started to sweat.

    These are some examples of what’s happening. The SOA rep got in the drivers seat, turned on the fan for 2 minutes then turned on the a/c. The air cooled down and that was the end of the dealership run. Both the manager and the r made me feel very stupid, again. I have worked on cars for over 10 yrs, so I do have a basic understanding of how a vehicle works
    Please help
    Adrienne

    • Justin Stobb says:

      Hello Adrienne,

      I was away at last week and my right arm is currently in a sling, so I am really behind in trying to help some folks out.

      Please understand I can only give general information with out seeing the vehicle, especially with a non typical type issue.

      Does the vehicle have a seat heater? Someone must ascertain where the hot air is coming from if its not the vents?

      Justin

  81. Mike says:

    I went to recharge my a/c unit at home, when I tested the PSI on the valve it wasn’t low, but instead it ran higher than the gauge could measure. What would be cause this to happen. It’s a 2005 out a k wagon.

    • Justin Stobb says:

      Hi Mike,

      The gauges that come with the DIY kits may not be very accurate.

      The vehicle has a High pressure relief valve so if it was actually pegging the gauge the system would have vented.

      Justin

  82. Steve says:

    Hi Justin,
    Just a quick question. Just had air serviced at dealer 2002 Forster. Everything seems to be working fine. But is it normal for both cooling fans to turn on when the air conditioner is turned on?? Another words. Everytime I turn on the air conditioner, The two Fans turn on as well, Even when the engin is cold. Is this normal??

  83. patrick hawkins says:

    I have a 95 Legacy Outback 2.2 standard, refitted for 134A. Recently the A.C. was being intermittent so I bought some 134A oil charge and added it. The clutch would engage for a second and then quit. In my Chevy truck that means adding more refrigerant until the compressor and clutch engage. I couldn’t add any more refrigerant to the Subaru because it wouldn’t take any. All the pressure was in the hose from the can of 134A. Because the clutch would engage, if only for a second, I want to believe the compressor and clutch are OK, but I have been overcharged where I live for simple things and I am very hesitant to take it back to them. I will go to a different town and have it done, but I want to do all I can to find out if I need to have the comp/clutch replaced, or have it evacuated and recharged. My Chilton’s manual doesn’t really talk about it much preferring taking it to the pros…which I would do if I need to. Any ideas…and thanks in advance for your help.

    • Justin Stobb says:

      Hello Patrick,

      Your Chevy Truck uses a low pressure cycling switch to engage and disengage the compressor the Subaru does not.

      It would be my suggestion to Throw the Chilton’s manual in the garbage and buy the factory manual if you intend to perform some of the service yourself. The 1995 Subaru came from the factory with R134a so it could not have been retrofitted, R12 was banned for use in all production vehicles sold in the US by 1994.

      With out gauge readings I have no idea if its low, overcharged, full of moisture etc. From there the Scan data showing the AC request and command cycles from the Engine control module is also needed.

      Sounds like you live in a small town, and that can be frustrating if they dont know the car all that well, it may seem to you that you are being overcharged but may in fact seem fair to them.

      Sorry that I cant offer much there just isn’t a every 1995 Legacy needs this kind of a thing I can suggest.

      Justin

  84. Garnett says:

    I have an 03 WRX. Last season my a/c worked lika a champ, yesterday when i turned it on only hot air came out. Investigation reveals that the clutch is not engaging. I have swapped out the relay and checked the fuse under the dash. I have 12vdc at the connection. I tried running a jumper to the back of the compressor and no luck there. Any ideas???

  85. ChrisB says:

    Hi Justin,
    I’ve just got a 2010 Impreza WRX STI, auto climate control and it seems to control the temperature but the dial has to be set near to max cold to be comfortable, is there any adjustment possible? The cabin sensor has been changed to no effect. Not a big deal normally but if you want to be a bit cooler the dial has to be turned to the max cold position, with the consequential high fan speed and back when cool enough.
    Chris

    • Justin Stobb says:

      Have you tried the Recirc feature?

      • ChrisB says:

        Hi, thanks for reply, sorry for delay I have been away. Recirc doesn’t seem to make any difference, but going to the full cold temp setting then it goes to increased air flow at very cold and automatically goes to recirc. It seems to have plenty of cooling ability but it is controlling to a too high temperature? Is there any calibration for the cabin sensor? It seems to function otherwise OK, if cabin is hot it goes to recirc with fast fan and air temp at 2 to 4C as the cabin cools the fan speed slows and then goes from vents to vents and floor at this point if no more cooling is needed the vent air temperature then rises to balance what is required but the temp control at times is one stop from the end! You mensioned Recerc was this as the brain does something different than controlling the air intake, does it change the algorithm? Chris

  86. Ben R says:

    Hey Justin,
    I have a 2004 OBW Base with some AC issues. I replaced a leaky hose, vacuumed down the system and refilled it. It almost immediately started squealing and occasionally making a strange fog horn like noise. I realized that I probably had over filled the system. I removed some of the refridgerent and then it worked great for a month or so.
    Currently, it runs fine at idle, but as soon as you rev it up it starts to squeak. Then the compressor will turn off and on every 2 seconds. If you turn off the car and start it back up, it will work great while idling, and the cycle continues.
    We are hitting the mid 90s for the first time this year, incase that is important to to situation.
    Thanks in advance for all your help.

  87. Erik Pierce says:

    Howdy all!

    Similar issue as many other folks here, 2007 Forester, intermittent AC operation: starts off frosty, goes warm some time afterwards (20-30 minutes?), stays warm for a short time (2-5 minutes?), then cycles back and forth between cold and warm.

    Subaru dealership is, unfortunately, clueless, so I’m taking to the internet streets, looking for a troubleshooting plan. So far, I’m guessing moisture in the coolant could be causing icing in the expansion valve, so a moisture removal process may be in order.

    Any other ideas?

    • Justin Stobb says:

      Hello Erik,

      Yes we have seen that issue, its going to either be the expansion valve or thermo sensor at fault. Gauge readings would help pinpoint it.

      Most likely when its blowing warm if you pop the hood and can locate the Expansion valve ( where the AC lines go into the Fire wall) you will observe it iced over. Surprised the Dealer didn’t look for that as that’s actually a common symptom on the Impreza and Forester models.

      Hope that helps and best of luck.

      Justin

  88. Richard Jones says:

    I have a 2003 Outback with the 4 cylinder engine. I love the car but my AC has a really weird problem. A few months ago I paid a mechanic to clean the evaporator which he said was full of leaves and dog hair from the previous owner. Every since then the compressor runs all the time unless I turn the fan on, the evaporator freezes up constantly, and the AC won’t cool unless the AC light on the dash is off. I don’t think the thermostat works, the AC is either on or off. I have been putting up with it but it is getting annoying.

    Any ideas. I don’t mind paying for a repair but I am afraid that this will cost a bundle to find the defective part.

    • Justin Stobb says:

      Hello Richard,

      With out gauge readings that’s going to be tough to come up with a possible solution. Especially with the ac only working with the switch off part? The rest would let me believe the Expansion valve has an issue

      Justin

      • Richard Jones says:

        The AC unit cools well when the AC switch is off so I don’t think it is a mechanical or coolant issue. I believe I have either an electrical problem, failed sensor or a bad control. I don’t mind taking it to an AC professional to fix it but I worry that the local “AC Experts” shop will charge me for their rabbit hunt to figure out what is wrong. The closest Subaru dealer is a long drive from here and is rather difficult to do business with. Based on the problem I am experiencing, do you think I need to go to the dealer?

        • Justin Stobb says:

          I am confused by this “The AC unit cools well when the AC switch is off”

          Does the compressor turn on and the high side line hot and the low side line cold?

          If the Ac works great when the Ac is off then just leave it off until you can have it looked at.

          Justin

          • Richard Jones says:

            Justin,

            Yes, everything works backwards. The AC compressor and cooling fans operate all the time the button on the dash is set to off. Basically the logic seems to be:
            Fan and AC switch on – AC compressor is off
            Fan and AC switch off – AC compressor is on
            Fan must on to get the compressor to shut off
            The climate control does not cycle the compressor according to cabin temperature, it is either on or off as described above.

            I have checked the AC relay with a test light. It had 12V on one leg at all times and the ground side is definitely being switched on/off but in the wrong logical direction. It obviously controls the compressor and cooling fan because they cycle with the relay.

            This situation started when I had the evaporator “cleaned” by a mechanic. He said it was full of leaves and dust. He does not take any responsibility for causing the current problem and I have looked under the dash and could not find any obvious wiring issues. I have taken the car to other automotive shops who work on AC units and they really don’t want to work on it. I contacted you just to get a clue of what to do from here.

          • Justin Stobb says:

            Where is the mode selector set during all of this is it possible its pointed to defrost?

            If someone removed the Evap core which would be weird as its in the dash and I don’t generally see them fill up with leaves then maybe the thermo-sensor was damaged.

            The car is capable of being diagnosed and very repairable but someone like us will have to do it and it will cost $.

            Justin

  89. Jolanda says:

    I have a 2003 Forester and this summer the AC has stopped working when I’m idling or driving less than 30 mph. What do you recommend?

  90. Jolanda says:

    AC in my 2003 Forester stops working when I’m idling or driving less than 30 mph. Any recommendations?

    • Justin Stobb says:

      Hello Jolanda,

      Most likely it has a low charge brought on by a leak somewhere. If you want it to work properly your going to need to have someone have a look locally to you.

      Justin

  91. Tom says:

    Hi,

    I have a 2007 forester, the ac went out, and I’ve been trying to diagnose the problem to send if its something I can fix. With the ac and fan on high, the ac blows warm air. Compressor clutch never started to turn. Purchased DIY can of coolant and attempted to recharge the system. Pressure gauge read high, in the red…so I took it to an oil change place and had them test it also way into the red from the low pressure side. Not over charged, didnt recharge, so is it air or what? Took it home, check fuses, all ok, jumpered the compressor where the wire harness connects to the battery and the compressor started to turn. Could this be the relay switch, pressure switch, etc? What’s my next step?

    • Justin Stobb says:

      Hello Tom,

      Jumping switches and bypassing controls is not a good way to accurately diagnose an issue and you need to use caution. I have witnessed inexperienced individuals do bodily harm working on an ac system and having it vent pressurized refrigerant into there face. this would be the case if the high side pressure cut out switch was bypassed when it actually was correctly not allowing the system to come on as the pressure was too high.

      To diagnose an issue with an ac system you first need gauge readings from both sides, then you need to see if the Ac is being commanded on and not doing so or if thee is no command, then figure out why. There are numerous relays, switches and sensors.

      You should start with purchasing the Factory Subaru service manual if you intend to service the vehicle yourself, not for this occasion but for all occasions now and going forward.

      There is no way I can know whats the matter from here.

      Justin

  92. Max Johnson says:

    Hi,

    My girlfriend has a 2003 Subaru Forester that is having A/C issues coupled with engine overheating only on days where the ambient temperature is >90°F,

    The problem presents itself with either freeway or city driving and only when the A/C is on and the outside temperature is >90°F.

    1. The coolant temperature begins to rise significantly above normal but not yet into the red zone.

    2. The air conditioning starts blowing warm air.

    3. The coolant temperatuere starts to fall. Sometimes she turns on the heater full blast to help bring coolant temperature down.

    3. Once the coolant temperature falls close to normal the A/C will again begin blowing cold air.

    Are there any A/C problems that would cause excessive heat generation at the condenser coil?

    I was also wondering if there was any connections between the cooling system the computer and the A/C system. For example if the coolant temperature sensor that sends data to the computer is reading an elevated temperature will the computer turn off the A/C system until the coolant temperature returns back to a lower level?

    Also, as overheating is a big concern to me what is the most likely cause of this overheating situation. Lets assume that the fans, thermostat, water pump, and radiator cap are all functioning properly.

    Does this point to the radiator based on the the fact that it only happens when its hot outside?

    It seems to me that the system only overheats when it is highly stressed. Hot outside + AC Condenser heating up air before it hits the radiator.

    It doesn’t seem like head gasket failure to me due to the specific curcumstances that need to exist for the problem to occur. But, do you think this could be the beginning of that type of situation?

    Let me know what you think and if there are any diagnostics that I should perform to point me in the right direction.

    I have some specialty tools like AC gauges and a multimieter.

    • Justin Stobb says:

      You need to address the cooling system, as soon as that gauge starts to move above the spot it sits all day everyday it is overheating, I don’t want to see you damage the car.

      I would read the two head gasket articles I have written on this site. From here I have no idea whats wrong, but you can not continue to use the car until the Cooling system is fixed or it will have blown head gaskets even if it was just a restricted radiator to start out with.

      Justin

  93. Dennis says:

    Hi Justin,
    Are you familiar with the AC system in a ’96 SVX? It was in a “minor” front end collision and, after replacing the condenser,the AC system was checked for leaks and charged. I tested it once on the way home and it seemed to blow cold air. Several days later, when it was very hot, I tried to use it and it cycled on and off rapidly. Each time it cycled on the engine would almost stall (it did once)and the compressor would immediately cycle off. Could this be an overcharged system on a hot day? What do you think it could be?
    Dennis

  94. Les says:

    Hello Justin,
    Do you know any reliable shops in Chicago area that specialize in fixing air conditioning systems. I have had a few troubles with my 2003 Subaru Legacy. Parts changed but to no avail, and it gets expensive. When refilled it cools for a couple of weeks but than when I stop driving for a couple of days, the system dries out. I need a real professional to look at it, tired of spending the money.
    Sincerely,
    Les B.

  95. Chris says:

    I have a 04 Outback with the H6 engine. the air is cold for the first 15 to 20 minutes then turns warm. I have tried the recharge kit, which didn’t help. If the car sits for a half hour the air will be cold then again warm after 15 minutes. Is there a temp sensor that could be bad? I see that this seems to be a common problem.

    • Justin Stobb says:

      Hello Chris,

      Common issues would be the Rev sensor @ the compressor or a sticky Expansion valve. The temp sensor in the Evap core could also be at fault, but less common than the other two items I mentioned.

      Justin

  96. Perry Hodges says:

    We have a 2007 Forester 4 with manual AC controls, very basic car. The AC will work fine some of the time and even for extended rides (1-2 hours). It will begin to transition from cold air to hot air other times. The hot air only lasts a couple minutes and then turns cold again. This may happen several times in a span of 20 minutes. This began about two months ago. Suggestions?

    Thanks,
    Perry

    • Justin Stobb says:

      Hello Perry,

      I would look at the Charge levels to start with, then at the possibility of a sticking relay. Has the Coolant temp stayed in the normal range the entire time?

      Justin

  97. hery says:

    hi justin i have 2001 subaru legacy 2.5 L
    And the problem i have is when i stop at a red light with the a/c on the car starts iddle in weird when is running is normal

    • Justin Stobb says:

      Hello Hery,

      As with most 4 cylinder models that have a large cabin area the engine can and will feel much different with the load of the Ac compressor engaging especially at idle.

      Justin

  98. Eric Brecht says:

    On a previous post you mentioned the ac compressor and the defrost being tied together. If this is the issue, then what is the likely cause?

  99. Curtis says:

    Justin,

    I have a 2002 impreza wrx and the ac is working sporadically. When I start the car in the morning and I instantly turn the ac on it will begin to cool down immediately. After about 10 minutes the air begins to get warm and will not cool down. Had the dealer look at it and they said the freon was a little low and also that the compressor is not compressing. After reading this forum I am sensing it might be something else. They quoted about $1000 for compressor replacement with labor. Thinking about doing it myself looking at the price. Is there another way to know if the compressor is doing it’s job? You have any thoughts??

    Thanks

    Curtis

    • Justin Stobb says:

      Hello Curtis,

      If the Charge of R134a (mistakenly called freon) is low there is no way to know the condition of the Compressor.

      the 2002 WRX has an issue with the Thermo-sensor, but I don’t know if that’s what is wrong with your car, just that its a common repair.

      Justin

  100. Steve Ransom says:

    Hi Jason,
    I’ve enjoyed your forum. Thanks for sharing your knowledge. I’ll preface my remarks by saying I’m an A/C contractor for residential homes and auto nut. My wife’s 2009 Tribeca has developed a knock/rattle when the compressor kicks in. It is cooling properly. Car has 91K on the odo. Dealer says the clutch is non serviceable.
    Am I correct in thinking it’s time for a compressor? I have all the tools to do the job but not sure besides the drier if other parts should be replaced while it’s apart. Your thoughts….Thanks

    • Justin Stobb says:

      Hi Steve,

      Its Justin not Jason thanks.

      If the Compressor failed and debris went through the system than it may need more, if it was just the clutch and the bearing in the compressor did not fail and send debris through the system you are on the right track.

      Justin

  101. Damien says:

    HI,
    What would cause a compressor clutch to disengage while in idle? I turn the car on, turn on the AC, both fans come on, the clutch engages and cold air blows then after a small while the compressor clutch disengages and the air then naturally blows warm. All this is during idle and not driving. I have a 2003 forester.

    • Justin Stobb says:

      Hello Damien,

      That sounds like it has a low charge. The Ac system in a car can lose up to 2 ounces of refrigerant a year with out there being a major leak. Because AC maintenance isn’t really covered in the owners manual, most don’t understand that the AC system should be serviced about every two years to avoid low charge and or performance issues. Or it could have developed a small leak regardless of service history.

      To know for sure gauge readings would be required.

      Justin

      • Damien says:

        A low charge will cause the compressor clutch to disengage and not turn back on again in idle? When the RPMs go up the clutch goes back on. I can tell because I can hear the belt chirp. Both fans are on in idle so air flow over the condensor is not the issue. I actually whitnessed the clutch stop while the car was in idle and both fans were going. It wouldn’t engage again unless I stepped on the gas and brought the RPMs up to about 2K for a few moments. So relays are good, fans are good. What is the proper PSI on the low side when the compressor clutch is engaged? and is there a pressure swtich that could be misreading?

        • Justin Stobb says:

          A low charge will cause the system to shut off at any time but so will a faulty sensor, relay or expansion valve etc.

          What I tried to do was give you the most likely, but I cant know whats wrong from here.

          Gauge readings will vary by temperature. With the car off they should be close to even, with the car running and the ac engaged the high side will range from 140 to 200 with a =/- factor of at least 10 lbs and the low side will range from 20 to 40 its when the low side drops down to less than 20 and does so quickly while the high side still has not reached 150 to 200lbs, that you can begin to assume a low charge would be one plausible cause and generally the ac will also possibly disengage when the pressure is low. Its at that time that you would add some R134a and see if the symptom improves. If not that would be ruled out and you would need to look elsewhere.

          Thats all I can offer you from here.

          -Justin

      • Damien says:

        I think My reply got deleted. I asked if a low charge will cause the compressor clutch to dissengage and not come back on at idle. What is the proper low side PSI? is there a pressure swtich that causes the clutch to disengage that could be bad?

  102. Stan says:

    ’98 Impreza 2.2 auto. AC was fine, funny smell, like solvent/plastic/ some vapor mist on humid day, then nothing. Garage re-charged and added dye. Worked OK onthe drive home. Sat for a couple days, upon morning start, I turned AC on, sounded like “spray painting inside a coffee can” sound from behind glove box AND that funny smell. I’m suspecting evap coil leak. I have call into garage for advice.

  103. erik says:

    Hi i have a 02 wrx with the ac pump cycling on and off and blowing cold then warm air i think it mite be the thermo sensor. But there is brown dust on the compressor behind the clutch. could the clutch or the compressor be bad? All so the system has been recharged several times by a mechanic friend and replaced 1 oring on the low pressure side.

  104. Erik says:

    02 wrx the a/c cycles on and off and blows cold then warm air. could this be the thermo sensor or the compressor? the compressor has some brown dust on the back side of the clutch housing?

    • Justin Stobb says:

      The dust is compressor clutch material.

      No idea whats the matter with it without seeing it. But in 2002/2003 the Wrx had a known issue with the Thermo-sensor and there is a TSB referring to it.

      Justin

  105. Ken says:

    The a/c on my 2006 outback seems to work fine while the vehicle is in motion but blows hot when sitting in traffic. I had the system serviced last fall.

  106. Randy says:

    Air conditioning failed in May on my 2008 Impreza. Vancouver, BC Subaru dealer diagnosed a failed evaporator and replaced it, refrigerant and cabin air filter for over $1100. We don’t use air conditioning a lot in Canada, but by July performance had decreased and by August failed completely again. This time dealer has diagnosed a small hole in condenser, which will cost another $800 – $1000 to replace. How likely is it that we really had both problems within 3 months of each other, as opposed to their just having made the wrong repair the first time? Seems likely to me that the first repair was just a mistake. Would like at least a second opinion. Thank-you.

    • Justin Stobb says:

      Hi Randy,

      Its just not possible to give you a factual answer, only to say that typically a hole in the condenser would affect the AC performance the instant it happened and not allow it to work for even one day if present, also rocks and other road debris are typically what take out the condenser. Even a small hole as the condenser is under pressure and pressurized refrigerant leaks out very quickly in most cases.

      It should have ben apparent to you if the evap core was at fault the last time as there should have also been an odor in the cabin when it failed?

      Maybe the Evap core diagnoses was incorrect, and usually when the Tech removes the core its wet with oil.

      Dont know if that helps but thats really all I can offer from here.

      Justin

  107. Randy says:

    Should mention too that odometer is at 55,000 kilometers (about 34,000 miles)

  108. Brian Wiggs says:

    Replaced the compressor, condensor, evaporator, and receiver drier in a 2001 Legacy. AC worked well, system holding pressure, blew cold air for 2 hours in shop. Customer picked up vehicle, AC worked well for first hour, now only blows musty air. Thinking relay or pressure switch…Subaru says they only sell switch with the receiver drier. Any ideas?

    • Justin Stobb says:

      Hello Brian,

      What are the pressure readings form the gauges? Is the Ac compressor cycling on? If so what are the readings and for how long, if not where is the power loss? Did it lose its charge if so why? If it still has a charge is AC request showing up on Scan data when the switch is turned on if not why? If so trace down why the compressor is not engaging. Switch, relay, rev sensor, TPS etc.

      I’ve never replaced the switch in question, that doesn’t mean its not at fault I just cant tell you whats wrong with out some information.

      You have some trouble shooting to go do, stick with it I am sure its repairable.

      Justin

      • Brian Wiggs says:

        Customer returned today, turns out it was a bad compressor and the clutch is locked up tight. Never had a bad compressor from this supplier, so was a complete surprise. Hopefully we won’t find debris in the system and it has to all be done over again. It was a terrible job!

  109. Bertille says:

    Hi all,
    I have a 2000 Subaru Impreza Sportswagon, naturally aspirated. In the US it’s called an Outback.
    I’ve been having an intermittent loss of power for almost a year now. I’ve cleaned injectors, replaced fuel filter, replaced MAF Sensor, replaced aftermarket air filter for stock, checked for vacuum leaks in the engine, replaced Oxygen Sensor (all new OEM parts) and each time the problem returns.
    Sometimes, the problem would present itself when I use the air condition, that’s what lead me to this forum.
    I’m really not sure if it may have some bearing on my particular problem, considering that it occurs generally when the ac is not being used. However, any suggestions on the matter will me appreciated.
    P.S. the Japanese version differs from the US version in several ways but I believe the physics used remains the same.

    Bertille

    • Justin Stobb says:

      Hello Bertille,

      I am a little confused with the below.

      “Sometimes, the problem would present itself when I use the air condition, that’s what lead me to this forum.
      I’m really not sure if it may have some bearing on my particular problem, considering that it occurs generally when the ac is not being used. ”

      If it happens both when the ac is on, and when not the Ac wouldn’t really have anything to do with it. Has anyone looked at fuel pressure?

      -Justin

  110. Steve M says:

    I have a 2001 Forester with A/C not working. The bulb in the A/C control panel switch appears to be defective because an ohmeter check shows an open and 12V will not light the bulb. The Alldata wiring diagram shows that the bulb is wired in series with the Evaporation Thermo Switch (which I can’t find and the dealer parts dept couldn’t either) and potentially the Engine Control Module. This suggests “No bulb, No A/C”. Does this make sense? Can a bulb failure truly render the A/C non-functional?

    Interestingly, the bulb is available through the dealer for $12 on a special order with 2-day delivery. This suggests that it is not an obscure failure.

    • Steve M says:

      The new bulb measures 50 ohms so I assume it will work. I live in Minnesota so I am waiting for a warmer than 10 degF day to install it. I am still puzzled about a design where if an indicator bulb fails, the system stops working. Anybody have any comments?

  111. Steve Muscanto says:

    Hi Justin,

    Thanks for responding. Did you have a chance to review the wiring diagram? Am I reading it correctly? Since you are a premier Subaru shop, do you have the ability to discuss this with Subaru tech support to see if they have encountered it? I am really curious about the rational behind the design.

    Steve

    • Justin Stobb says:

      Hello Steve,

      I have not had a chance to review the wiring diagram for your vehicle. There are simply not enough hours in the day.

      Like I had said earlier, I had not seen that before but have replaced the control unit for loss of signal.

      -Justin

  112. Jennifer H. says:

    Good afternoon,
    I have a 2000 Subaru Outback Wagon with a manual climate control knob (half blue, half red). The A/C worked great until I started using the heat this winter. Every time after switching back from heat, the heat would take over a little bit of the blue side. Now over 90% of the blue half of the control is heat, and only the bottom 10% is A/C.
    When I brought my car in for service the first time the mechanic understood my problem, but didn’t have time to fix it. When I came back a second time, a different mechanic was there that had never heard of my problem.
    Have you heard of this before? Can you tell me the correct terminology to use to get my problem fixed?
    Thank you for your knowledge!

    • Justin Stobb says:

      Hello Jennifer,

      Yes the blend door is not working correctly this is what regulates the door in the heater case to control the blend of hot vs fresh or cooled air.

      What has to happen is a diagnoses must be performed to know why this has occurred it could be something is broken or just out of adjustment.

      -Justin

  113. Emeka says:

    Good Day,
    I love this forum. I have a 2008 legacy sedan. I have been experiencing poor cooling for some months. Each time i refill the gas it works for just a while. I Was told it was a leakage problem. Where else can leakages come from? Checked the engine compartment but found no leakages.

    • Justin Stobb says:

      Hello Emeka,

      It has a leak, not sure how you are looking for the leak but there is a analyzer that is designed to sniff out gas leaks., is that what you are using if so the next step is dye in the compressor oil, lastly small leaks can be difficult to diagnose.

      -Justin

  114. Neil Youngson says:

    Hi Justin,

    I have a 2003 Outback 2.5L auto with about 124,000 miles on the clock, and for the last six months or so have had an a/c system that would blow cold when the car was first started but would sometimes then blow hot. If I stopped for a few minutes it would usually blow cold again. Eventually it stopped blowing cold altogether so I took it to a local garage who recharged it and it blew cold for a week or so but now just blows hot air.

    The fans work fine and the clutch engages when the a/c button is pressed. I thought I had a leak so bought some O-rings and a can of sub-zero R-134a but on pressing the low side valve with a screwdriver there seemed to be lots of pressure so I attached the gauge hose of the sub-zero and it read 50+ So now I think that a leak is not my problem.

    I swapped the relay for the fog light relay which is the same spec and that made no difference.

    It seems to me odd that the previous problem was fixed by a recharge but now it no longer blows cold even though there seems to be plenty of gas on the low side. Could the gauge reading be wrong from the sub-zero can and should I try recharging?

    Any other suggestions as to the likely cause?

    Many thanks
    Neil

    • Justin Stobb says:

      Hi Neil,

      I would say the system has a leak, most likely at one of the AC hoses, then you tapped into the system without putting into vacuum for 30 minutes prior to recharging and oiling?

      -Justin

  115. Neil Youngson says:

    I forgot to mention that the pipes on the low pressure side do not feel cold to the touch.

    Thanks
    Neil

  116. Michael Dunne says:

    Hello .My 2005 liberty 3 ltrr has a sort of a rattle sound when the compresor kicks in. Can you tell me if this is a easy fix or not.

  117. Chad says:

    Greetings,

    I have an A/C issue I am hoping you could help me with.

    In August 2013, the A/C in my 2011 WRX starting working intermittently. The recirculation and A/C light would stay on, however the air would blow cold for 10-30 seconds then compressor would kick off and blow ambient air for 10-30 seconds. It would continue this time cycle. It eventually got worse enough so the A/C would not kick on except 3-4 times during a 20 minute drive.

    The Subaru dealership replaced the A/C relay (Part# 82501AG041) which didn’t help. Then they replaced the thermosensor (Part# 73540FG011) and this fixed the issue.

    Fast forward to yesterday, March 10, 2014. It is getting warmer here in Louisiana, and I am using A/C more often. The issue has appeared to come back. The air will blow cold for 15-20 seconds, and then blow ambient air for 5 seconds. I can only imagine this will get worse just like last time.

    I just got off the phone with the dealership and the part is covered under warranty, but not labor. I don’t want to spend another $600 on another temporary fix.

    Any ideas of why this issue might come back? Think its a defective part or is there another part causing the thermosensor to malfunction?

    Any assistance would be greatly appreciated!

    • Justin Stobb says:

      Hi Chad,

      Love New Orleans!

      I am seriously confused as to how a shop does not have to warranty all repairs for a term of at least 12 months or 12,000 miles.

      Your 2011 WRX has a 3 year 36k bumper to Bumper warranty and if you are having an issue with a already repaired item, I would call SOA at 1800 Subaru 3 and state your case. If the car is not already at the Dealer (I wasn’t clear about that) Subaru is going to tell you to take it in, that’s the first step.

      Hopefully Subaru will come through for you and take care of it.

      -Justin

  118. Chad says:

    Thanks for the reply Justin. I will bring it in next week and will let you know what the verdict is.

    Appreciate your help!
    Chad

  119. Ken Aubel says:

    Justin,

    Nice site, I’m hoping you can help point me in the right direction…

    2000 Subaru w/245K miles, trans replaced under warranty @ 60K miles, suffers intermittent blown AC/blower fuse under acceleration. AC blows cold, car lurches when fuse blows likely from AC clutch disengaging. Problem started @ 180K miles and has increased with mileage.

    Had previous diagnostic run, unable to duplicate. Seems to occur more often when car is heavily loaded or when driven more aggressively. Doesn’t seem to occur when only the blower (No AC) is on.

    Transmission does shift somewhat ‘hard,’ especially when starting from park & shifting into reverse, producing a fairly loud ‘clunk.’ Both transmissions always somewhat balky after first 40K miles.

    Live in California, so AC gets constant use. Possible AC clutch and/or relay or other? We keep a box of 15amp fuses and can swap in less than 1 minute once stopped…, but tired of this. Recent 250 mile, 6 fuse weekend trip with heavy load.

    Thanks in advance,

    Ken

  120. Ken Aubel says:

    Justin,

    2000 Subaru w/245K miles, trans replaced under warranty @ 60K miles, suffers intermittent blown AC/blower fuse under acceleration. AC blows cold, car lurches when fuse blows likely from AC clutch disengaging. Problem started @ ~180K miles and has increased with mileage.

    Had previous diagnostic run, unable to duplicate. Seems to occur more often when car is heavily loaded or when driven more aggressively. Doesn’t seem to occur when only the blower (No AC) is on.

    Transmission does shift somewhat ‘hard,’ especially when starting from park & shifting into reverse, producing a fairly loud ‘clunk.’ Both transmissions (original & replacement) always somewhat balky after first 40K miles.

    Live in California, so AC gets constant use. Possible AC clutch and/or relay or other? Refrigerant level checked and still blows fuse. We keep a box of 15amp fuses and can swap in less than 1 minute once stopped…, but tired of this. Recent 250 mile, 6 fuse weekend trip with heavy load.

    Thanks in advance,

    Ken

    • Justin Stobb says:

      Hi Ken,

      So the Ac fuse blows, but I am not sure why you are telling me about the transmission?

      Has anyone looked at the Ac compressor clutch circuit? That’s the place to start. You could disconnect the AC Compressor electrically and go drive it hard and see if the fuse still blows. If not that kind of tells you that there is something wrong with the circuit that needs to be evaluated, its not going to be a cheap or easy diagnoses and you will need to find someone that will stick with it. If I had to guess the gap of the clutch is to tight.

      The 2000 E4AT transmission was the single worse one Subaru ever built. It may continue to work with symptoms for another 50k or it could become worse next week.

      -Justin

  121. Ken Aubel says:

    PS – Didn’t clearly state that this fuse blowing symptom/issue seems to occur during or immediately after the shift and that this is an automatic transmission.

  122. Ken Aubel says:

    I have a 2000 Subaru GT wagon H4 w/245K miles, auto trans replaced under warranty @ 60K miles, suffers intermittent blown AC/blower fuse under acceleration (seems close to or at shift point.) AC blows cold, car lurches when fuse blows likely from AC clutch disengaging. Problem started @ ~180K miles and has increased with mileage.

    Had previous diagnostics run, unable to duplicate problem, no other issues or codes. Seems to occur most often when car is heavily loaded or when driven more aggressively, especially at the 2nd to 3rd shift. Doesn’t seem to occur when only the blower (No AC) is on.

    Transmission does shift somewhat ‘hard,’ especially when starting from park & shifting into reverse, producing a fairly loud ‘clunk.’ Both transmissions (original & replacement) always somewhat balky after first 40K miles.

    Live in California, so AC gets constant use. Possible AC clutch and/or relay or other? We keep a box of 15amp fuses and can swap in less than 1 minute once stopped…, but tired of this. Recent 250 mile, 6 fuse weekend trip with heavy load.

    Thanks in advance,

    Ken

  123. Ken Aubel says:

    sorry, when I go to website, it doesn’t show any of my postings even though on this page (below) it shows multiple…?

    http://allwheeldriveauto.com/subaru-air-conditioning-explained/#comment-271003

  124. zac says:

    Hey Justin,

    Great page! Lots of great info.

    My question is I have a 2003 forester automatic with mechanical a/c controls and after this winter in Colorado I no longer have cold air when the a/c is on. It has worked great since I bought it five years and had finally given out. I have verified that the compressor is working so my thought was a leaky line or just ask out of freon. I was a mechanic in my past life and I would like to figure it out myself. What tests can I do with what tools before I let someone else lay a hand on my car.

    Thanks Zac

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