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Why Changing Your Oil In Your Subaru Every 3000 Miles Is A Must For Most Drivers

 

I often have conversations at the shop about oil changes.   There are a lot of different opinions and as a result a lot of confusion.   But the reality is that oil changes are a very necessary part of your Subaru’s  longevity or lack thereof if not done as often as needed or done with poor quality parts.

All car manufacturers have a normal and severe maintenance schedule, and if you’re driving habits fall into the manufactures definition of normal then maybe it makes sense to follow that schedule.  But if you use your Subaru or any other car you drive in any fashion other than starting it up getting on the freeway where you travel at freeway speeds until you reach your destination where you shut it off and then repeat this use in this fashion the majority of the time you drive it, than you do not fall into the normal maintenance schedule.   The real reason for the different maintenance schedule is to give the appearance of having lower ownership costs.

I have heard to many times that a customer thinks that changing the oil every 3000 miles is something a well known lube center dreamed up.   The marketing of the 3 month or 3000 mile oil change service was taken to new heights by the lube centers, but they sure didn’t dream up the idea. 

When I started in auto shop we learned that the hardest thing an engine goes through is the heat of the summer and the cold of the winter.   You should start the summer season with fresh engine oil and once the summer is over you should change the contaminated oil out of the engine as the excessive heat can be detrimental to the effectiveness of the oil.  Conversely the engine should start the cold of winter with good fresh oil and sometimes a thinner grade of oil should be used to help the cold oil get to the top end of the engine quicker.   Once the winter season is over the sludge that once was oil should be drained out.   There you have it, the 4 oil changes a year your car should have. 

I know there are companies out there telling you that if you use their synthetic oil you can forgo the 3000 mile thing.  I have heard customers and read forums on line talk about having an oil analysis done to prove the oil was still ok 5000, 7000 and even 10000 miles from new.   But is the oil filter still working?   Does oil that still has lubricating properties mean that it is ok?  While synthetic oil can stretch out the oil change interval the level of the oil should be monitored very closely regardless of the product used.  The other fluid levels in the car such as the coolant need to be topped off periodically as well and the tires inflated too.  If the service interval of the oil is stretched out the service of the rest of the car suffers as well.

How does the whole system work?   Oil lubricates and cools the engine; in fact the oil in your engine is about 1/3 of your engines cooling system.  As the valves open and close, the pistons move up and down it is oil that keeps the moving parts moving easier.   The engine is the hub of your car it all starts with the rotation of the engine, the easier the job the engine has of all of its parts moving freely the easier all of the parts the engine is in turn supposed to turn will move as well.   Yes slacking on oil changes poses ramifications to more than just the engine itself.

As the engine is injecting fuel into the cylinders to provide the explosion that powers the engine not all of the fuel is burnt, we do not achieve 100% combustion with the internal combustion engine.  The excess fuel slides past the piston rings and into the crankcase where it mixes with the engine oil.  Over time a lot of excess fuel can end up in the crankcase.   The fuel mixed with the oil can degrade the lubricating properties of the oil and lower the flash point of the oil as well.  Another words the longer the oil is in the engine, the more fuel it collects, and as this oil fuel mixture is used to lubricate the parts in the combustion chamber the more likely it is to burn away, out of the engine into the exhaust and out the tail pipe.  Over time the engine can burn a significant amount of engine oil.  Next fuel is a solvent that can and will eat away at seals and gaskets causing leaks that will need to be repaired.  Try pouring a thimble full of gasoline on asphalt and watch how easily the fuel eats away at the road.  Imagine what contaminated oil can do over time to the head gaskets in your Subaru.

There are systems in place designed to help remove the fuel from the engine oil, one is the positive crankcase ventilation system or PCV, the other is called the breather hose, or breather tube.  On a Subaru you will find a rubber hose attached to each valve cover gasket and then traveling up to the air intake tube. 

Here is how the system should work, once the engine oil gets up to temperature the fuel vapor and contaminates can separate themselves from the engine and this vapor can be pulled back into the intake manifold and be re burnt or introduced back into the combustion chamber.   This helps clean up the engine oil and prolongs the oils life.  

Here is the problem with this, if you get in your car and make short trips, or spend a lot of time “idle” in traffic this is never going to happen in your car.   And this is why maintaining your Subaru based on how YOU use it, is the only way to get as much value out of your car as possible.

Ask yourself if you think the car companies really want you to keep your car 10 years take care of it and have it last or buy another car every 4 years.  

Next imagine that you own a factory with rows of equipment that all needs maintenance on a regular basis or the chance of the equipment failing and costing you money and down time will greatly increase.   Do you think most informed business owners will follow a strict schedule to maintain the equipment, thus keeping profits high and replacement costs down or rather roll the dice and stretch it out.    The similarities are there.  

Except that we often get caught up in this crazy notion of blue book value dictating how much  money we should put into a car instead of looking at replacement costs or the total value of keeping what we already own in good shape so it will last, but that is another article to write at a later date.

 

Here are some pictures of a 1997 Subaru Outback 2.5l Engine with less than 100k on it that had engine oil leaks at every possible location.  The owner admit tingly changed the oil every 7500 and has no idea what kind of oil was used.  The sludge build up is not good at all.  Over ten years the $500.00 or so in savings by stretching out the oil changes has been more than made up in mechanical repairs.

 


 

 

 

 

 

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 (26)

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  1. Scott says:

    Wow Justin,

    That is great advice, keep up the good work.

    See you soon for an oil change too by the way

    Scott

  2. name says:

    Changing the oil doesn’t prevent gasket leaks. Nor does it prevent electrical failures or problems with the fuel system, etc., etc. My 30+ years experience says getting a good car is a roll of the dice. I’ve bought second cars of the same model because the first car was great; only to have the second car be the worst car I’ve ever owned. Changing the oil more frequently than twice a year just wastes oil no matter how you drive.

    • Justin Stobb says:

      I am sorry but your thinking about this in the wrong frame of mind. You also wont like my response to your post but its intended to educate not offend.

      You will notice the title is “Why Changing Your Oil In Your Subaru Every 3000 Miles Is A Must For Most Drivers”

      The logic behind comments like this is exactly why the Auto Repair industry is a multi billion dollar industry. You can literally clean an oil slick up with a small amount of fuel, but somehow the concept of this also happening in your engine is lost to any that didn’t actually attend some sort of formal training like a 2 year trade school.

      A contributing factor to gasket and seal failure on a Subaru due to the design of the H or boxer engine is contaminated fluids. A real lack of understanding about how well or rather how poorly the combustion chamber is sealed away from the crankcase and what happens when fuel is mixed with oil and the diluted oil is circulated around the engine is common place through out the industry.

      Poor some gas on a rubber seal or better yet dip a rubber seal in a container of oil and gas mixed and tell me what happens over time.

      Fuel is a solvent that deteriorates seals, corrosion from old coolant will cause gasket, seal and block damage.

      I truly attempt to educate about why oil is the cheapest insurance you will ever buy. Old oil affects seals and gaskets, friction thus engine wear, fuel economy and the performance of the entire drive train. It is one of the first things you learn if you receive formal education rather than just on the job experience.

      My industry is plagued with individuals that understand how to take it apart and put it back together but no real understanding about the separation of oil vapor form oil liquid at a specific temperature and how this really doesn’t occur for the majority of us stuck in the “Rat race” during our commute and as such oil needs to be checked and changed as needed based on how the vehicle is driven, some fall into every 3000 miles some every 7000 miles but assuming your the 7k type, or someone else reading a post does and having a engine fail or a gasket leak earlier than the guy who changes it every 3k is how your ownership costs go up. Its called counting your nickels only to have 50 dollar bills fly a way.

      The parts in a car are all made the same way, assembled mostly by machine and have exacting standards, the only variable is the use of the vehicle after purchase. There are some cars that have defective components but that is a whole different conversation.

      When I plead with Owners across the country to change their oil, check there oil and take responsibility for all of the aspects of car ownership its so there are no surprises, no major mechanical failures, no financial hardships.

      Planning on changing your oil twice a year and driving the vehicle in a way that dictates more maintenance than that is just a repair waiting to happen, either to you or worse the next owner.

      Justin

  3. Tomasz Jarzecki says:

    Hi, Justin. Got an ’03 Outback with 106K. So far, so good. Love the car. I am the second owner and for the past 15,000 I have been running Mobil 1 synthetic with non OEM oil filters (Bosh, Mobil 1, Purolator) I live in Ohio and the oil change interval I set is 5000K. After reading your posts I am considering switching to 3000K oil changes. I am also thinking of switching back to conventional oil to offset some of the cost. I heard somewhere that once you go “synthetic” you should not go back to dino juice…. Thoughts???

    • Justin Stobb says:

      We use 5w30 Synthetic blend oil for 90% of our customers and Full synthetic for the rest.

      Oil is one of those things that everyone has an opinion about, I like blend oil done every 3000 to 4000 miles. Followed by Synthetic and the same interval, the Subaru oil filter is just to small to let it stay on for much longer than that. Some people will just change the filter, but I am not a huge fan of that either. Its a piece of machinery and the less friction the rotating mass incurs the better off it will be, I use that one rule and that one rule only. Everything else gets clouded in the conversation about oil and intervals. There for example are many on the WRX forums who hate Mobil 1 and feel it caused rod bearing failure in their engine. I personally like Mobil one but not as much as I like Motul and Enos, which is why our shop stocks the later 2 choices. Does that mean Mobil one shouldn’t be used? This is what I mean by cloudy.

      Justin

      Justin

  4. Dechen says:

    Hi I just bought a 1997 Outback and they have had synthetic blend oil in it. I am thinking of switching back to regular oil because it is cheaper. Is that ok for the car? Thanks.

  5. Dechen says:

    Hi…what is the spark plug gap on a 1997 Legacy Outback 2.5L DOHC? Thanks

  6. Hans says:

    Justin, great advice. I do about 4000 miles a year (retired) should I change the oil more frequently – every 6 mths – or is once a year enough? thanks

  7. Rahul says:

    So much bad information and assumptions gathered together in a sigle page is really impressive. Having your oil analyzed is the only way to really know what is going on. When you get your oil analyzed they will included the amount of contamination including how much the gasoline has diluted and broken down the oil and particulates which would indicate weather or not your oil filter is still working. Every mechanic has opinions. 2 year trade schools do not make one a biochemical engineer no matter what your mechanic tells you. Change your oil and filter as often as makes you feel good. If you go longer than recommended get your oil analyzed. Opinions are like a__ holes, everone has one. You dont need to listen to mine either. :0)

    • Justin Stobb says:

      “So much bad information and assumptions gathered together in a sigle page is really impressive”

      I sure hope you feel better after saying that?

      Do you really contend that spending $30.00 for an oil analysis, then spend money to change the oil is worthwhile? Do you understand the reasoning behind an analysis? Probably not, I will let you in on a secret.

      Oil Analysis, was a test intended to help fleet owners better know the condition of the internal components of the internal combustion engine, mainly large diesels and mostly to know when it was time to do a rebuild, so it could be planned for and downtime known about. But in a Capitalist Society like the great one we live in, you can’t stop there, you need to sell your idea to the world to expand the bank account, this is where the DIY crowd fits in.

      Should this be part of your maintenance plan? If you believe so by all means, but what would the average driver gain from this!

      Back in the “Ole Days” there were these guys called “carpetbaggers” that sold “snake oil” to folks of all sorts of intelligence levels, your rogue scholars all the way down to just plain stupid. It was never about the product, it was in fact one of the first examples of successful marketing of a products additional uses above and beyond its original intent.

      Next I find it incredibly rude, short sighted and ignorant that you would try to belittle someone who as at a minimum obtained some education in the chosen field they have pursued. I am not even talking about myself, but those in my industry that are constantly at odds with those that mock the profession as somehow lesser than their own.

      A life time as a “Biochemical Engineer” does not make you qualified to be an expert on the internal combustion engine, regardless of what the voices in your head may be telling you.

      Yes, I believe that someone who has studied and then mastered with experience the subject of Automotive Technology has an advantage over someone who studied say, Quantum Physics for 8 years when it comes to the true design and function of a dedicated system within an automobile. But you won’t find too many Automotive Technicians that think because they reflashed an ECM yesterday they are now masters of the universe, we’ll leave that up to the “Smart Folk”

      You may somehow believe your intellect superior, and you are most welcome to that opinion, what I try to point out is there is a reason to go to school, training or an apprenticeship program before becoming a Technician, I work in this industry I have seen good techs and bad, there has always been one constant, the ones that let in a little education around the factual aspects of the combustion engine, tend not to skip the most basic of details when suggesting maintenance.

      Its the ones that formed their own opinions based on “internet knowledge” often found on forums, typed in stupidity by the very “engineer types” that believe their singular wit superior to the rest of the human race, and seem to have an expert opinion on everything from Apples to Zebras.

      Lastly, checking and changing oil is as basic as it gets, I don’t believe in trying to over complicate it for the average family of four trying to get through today’s overworked, hussle and bustle by suggesting they send the oil out to be “anal” yzed.

      The round tire still rolls the best, checking your oil, adding when its low, and changing it when its due is still the best way to avoid engine failure, even if there are those that would like to reinvent the wheel.

      The point of the article is to help some Subaru owners avoid engine failure by not understanding what they own and how to maintain it based on their use.

      What I deal with on an almost daily basis is an owner that does not understand the very basics of car ownership either from lack of understanding or lack of desire to understand, the last thing I am going to do is over complicate it for them.

      Justin

  8. Dave says:

    Hi Justin – I’m a big fan of your website and I’ve gained a lot of insight from reading your articles and posts. In fact, I bought a 2001 Subaru Impreza (EJ22) for my son and we found out later that one of the head gaskets was bad. We pulled the engine and did the work ourselves and it’s running fine now, I believe in large part to the information I gained from your website.

    I recently purchased a 2009 Impreza Outback Sport with 69K miles on it. I’m working out of state during the week and driving back on the weekends to see my family – it’s a 1000 mile round trip (all expressway), so I think it puts me into a “normal” maintenance schedule. I purchased Mobil 1 oil with the long life filter when I changed the oil last time with the idea that it would give me a 15,000 mile interval between changes.

    Based on what I’ve read in your article, it seems that maybe I’m expecting too much from my oil? Is my driving situation unique enough to consider the long life that is advertised for the full synthetic oil? Ultimately, I’m trying to do what’s best for the car – I take a lot of pride in maintaining my vehicles. I’d prefer not to have to change the oil every 3 weeks, but if that’s what is best, then I will.

    Keep the good information coming!

    • Justin Stobb says:

      Ho Dave,

      I think that based on the drive you are ok going out past the 3000 mile mark up to 5000 miles most likely, and perhaps even little higher. What I do want you to do is monitor Consumption after 2500 miles, and use that info as a tool as to when you should consider changing it.

      The more it burns, the more its diluted, the more its diluted the more its a solvent, the more its a solvent the more particles end up in the filter.

      Hope that helps.

      Justin

  9. Desertboundwrx says:

    Man why cant people just allow the wheel to be round! A bit late to point out but even with oil “analizing” it doesnt prove that the filter isnt going into bypass or will soon. March 1st is just around the corner so its a good time to start a 3 month oil routine. Ever thought about getting a shop down in San Diego?

    • Justin Stobb says:

      Thanks for posting!

      There just isn’t enough of me to go around to ever consider expansion beyond one good shop.

      Thanks

      Justin

    • Noah says:

      Here Here. I live in Redding, CA and there is not a single independent Subaru specialty shop within driving distance, despite the streets crowded with them. I wrecked my Outback and couldn’t afford another one this go around, but I will have one again. Thanks for the good info Justin. Half of everything I learned what to do on a Subaru started by reading your blog and follwing your website.

  10. Nate says:

    Hey Justin,
    Got my first subaru- a used 2005 outback 3R in January. Going for first oil change as i write this. I had been reading your articles for the past 6 months and everything you wrote had positively influenced my selecting and buying subaru and how i am going to keep it. Just wanted to say thanks for all the advice you put out there.
    Keep the good work going..
    How about opening shop in canada? Lots of Subarus out here I think..

    • Justin Stobb says:

      Hello Nate,

      I love Canada, some of the most beautiful Country I have ever seen and as I am an Outdoor enthusiast so we would get along just fine. However it looks like opening a shop up there would have a lot of challenges from what I have heard from discussions with shop owners. We have had a few come down here from BC for larger repairs.

      Congrats on the Subaru I hope it gives you years of good service.

      Justin

  11. Joel Young says:

    I think Justin is right. I have always changed my oil and filter at around 3,000 miles. My 1998 2.5L Outback has 216,000 miles on it and does not use oil between changes, and is driven about 60/40 city/highway. The only engine work I have ever done was installing All Wheel Drive’s updated head gaskets at 202,000. When I removed the heads there was virtually no sludge in them. I dropped the heads at the machine shop in the a.m. and gave them carte blanche to do whatever was needed, and returned home from work in the p.m. to a phone message saying to come get them. The machinist said they needed zero work on the valves, guides, and cam journals. I had them lightly surfaced and put them back on.

  12. yemaya says:

    hi, I was going to change ignition wires and plugs when I discovered oil filled the plug cavities when I pulled off the old wires… Would this be a gasket issue? Like remove the valve cover, replace the top gasket, plus round gaskets down some rod by the plugs? Guy at a parts store said there’s a kit… that may remedy the oil leaking. Would appreciate your input. 2000 Subaru Outback with about 150K miles. Runs good.

  13. Scott McFadden says:

    Hi Justin,
    Thanks for post. I wish I lived closer to your shop but, alas, I live in Portland.

    I have a 2005 STI with 160k miles and am experiencing some oil consumption. I change my oil every 3400 miles.

    I know that my driver side exhaust cam seal is leaking from inspection. Before I change this seal which doesn’t seem to be coating my timing belt, I thought it might be a good idea to inspect and change the PCV and hoses. In your experience, does this seem like a correct approach to you? Have you had this issue before with PCVs on this motor? As far as I know, the PCV has never been changed. Everything else has been maintained to Subaru’s recommendations (t-belt, water pump, and idlers) Is there anything else you could recommend checking to see if I am not dealing with a bad seal but an over pressurized crankcase due to bad ventilation?

    Thanks!

    • Justin Stobb says:

      Hi Scott,

      Id start with an inspection of the PCV and replace components as needed, Oil consumption on your model could be the turbo so I would have a look at that as well. Unless the cam seal leak is large I might hold off until I had a handle on the Consumption, as if you replace the seal only to figure out the oil rings are worn it was a lot of work for not.

      -Justin

  14. Ashley says:

    Hi Justin!
    I am so thankful for this post! We just bought a 2014 Subaru Impreza. We are new to the Subaru world! For a 2014, would you recommend oil changes at 3,000 miles (with it being a new model)? We live in AZ, and drive the vehicle about 10 miles/day. Do you have any recommendations about this vehicle/maintenance?

    Thank you for your posts! They are awesome!
    Ashley

    • Justin Stobb says:

      Hello Ashley,

      Thanks for the post, you may be okay at a 5,000 interval with the 2014. I would check the oil every few fill ups and monitor oil use and the condition of the oil based on how you are using it. During the summer months it may use a little more oil due to the heat and the Ac use.

      Hope that helps

      -Justin

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