Subaru Service Seattle: Subaru Oil Filters Explained
Subaru practices lean manufacturing, and as a result if they can eliminate part numbers to keep things simple they will greatly lower their costs, but there are some unintended consequences sometimes.
Nowhere is this more obvious than their oil filters and how they have changed, superseded and morphed through the last few years.
The O.E. oil filter you buy for your older model Subaru today looks nothing like the one it came with or was installed for years, but in Subaru’s quest to keep things simple they have decided to not make available the older oil filters, but instead have shrank the size of the filter and dropped the older part numbers from production and inventory.
Pictured below are the last 3 oil filters used by Subaru for the 4 cylinder model. The black one in the middle was first used on the 2002 WRX turbo models, the reason for this is the Turbo models exhaust system runs very close to the oil filter and it was necessary to shrink the filter down to keep the oil filter from getting to hot and thus increasing the oil and engine temperature. Here is where things have gone from there, we used to install the black filter on the turbo models, the white filter on everything else except for the H6 and the Loyale. Then Subaru dropped the white filter from production, but wait a minute any one can see the white filter is bigger! The oil filter now used by Subaru on all 4 cylinder models is the blue one, which is even a little smaller than the black one and yes still much smaller than the white one that was used on your non Turbo model Subaru for years. I also want to point out the location on the engine for the oil filter on the 4 cylinder Subaru models has not changed since the Legacy came out in 1989.
If you own a Turbo model Subaru and don’t change your oil and filter at least every 4,000 miles you will most likely buy a Turbo or worse an engine, this is the current theme in the 2005 and newer Legacy GT, Forester XT and Outback XT models.
Before there is any argument about synthetic oil and oil analysis, the oil filter used by Subaru is very small and will not last the 7,000 miles your synthetic oil may last, oil analysis has no way of catching the slow clogging of the oil feed line to the turbo. Damage from extending the oil changes can happen very gradually over time or can ruin your trip in mere seconds and be very costly.
If you change your oil twice a year versus 3 to 4 times a year you will save roughly $800.00 over a ten year period. The bad news is you will most likely buy a Turbo and the Turbo will cost over $1200.00, just for the part! Add to that labor, gaskets and the possibility of the Turbo damaging the Engine just for fun.
If you own a older model Subaru (pre 2005) and the dealer is now installing the blue filter you are now cutting the filtering capacity and oil capacity down from how it was originally designed, and if you exceed the ability of the filter to filter, it doesn’t filter and contaminants in the oil will circulate around in the oil rather than be caught in the filter, this is done as the filter becomes restricted by the bypass to protect the engine from ever being starved for engine oil.
Subaru changed the exhaust lay out of the header pipe in all of their four cylinder models to resemble the Turbo models and now all of the 4 cylinder models have the exhaust system running very close to the oil filter rather than on the turbo models. So all current production models get the small oil filter as such there is no need for Subaru to keep making available the bigger oil filter even if it would be more beneficial to your 2004 Outback or your 1992 Legacy.
At our shop we use the Blue filters on cars still covered under A Subaru warranty to just keep things simple, and try to explain that the ramifications of going to long with the little blue filter won’t show up until the car is out of Warranty and its all your car. We install a large oil filter on models that don’t have a turbo or newer exhaust system. For turbo and 05 and later models we use a filter closer in design to the black filter as the Blue filter leaves a lot to be desired and anyone (minus the engineer who designed it) when holding the blue and black filters in their hands side by side will agree the quality of the filter is just not the same as it used to be.
The good news is Subaru did lower the price of the blue filter a little.
When I see things like this I will always try to find a solution to deliver more value than just going along with a corporations desire to cut costs. While I will also never claim to be as clever as the engineers, I will also never lose the argument that reducing oil capacity and filtering capacity is a bad idea. I kind of seriously doubt accounting ever consulted the engineers anyways.
Thanks for reading
Justin
Hey Justin,
Thank you for the great article above. Great timining since my mechanic and I were just discussing oil filters the other day. What’s the low-down on smaller filters increasing oil pressure, and if they do is it a go thing?
Your article mentioned “We install a large oil filter on models that don’t have a turbo or newer exhaust system.” Would you mind giving out the brand and part number of this larger filter?
I live on the east coast so using your shop for repairs isn’t likely. However, I would like to thank you very much for all the repair information on your site. This has been a great help to me and my mechanic (small independent shop) as we try to keep our three againg Subaru’s on the road in top shape.
Thank you again,
Bruce Brown
Le Roy, WV
95 Impreza coupe 200k
95 Impreza wagon 193k
96 Outback 201k
Interesting, and kind of disconcerting, article, Justin. Thanks for the info.
Would you please be more specific about what oil filter you now recommend and use for an out-of-warranty 2003 4 cylinder (not Turbo) Outback Wagon? Such as: manufacturer, and model and/or part number? Thanks!
Bruce and Gary,
The oil filters we use are imported from Japan and made in Thailand. They are basically the oil filters that are used in the non U.S. market which is a pretty consistent theme for how we buy our parts. Like The U.S. turns to Mexico, Canada and now China for much of its parts production Japan uses Thailand and other countries as well.
Unfortunately U.S. based companies such as Fram (Allied Signal) have such a strangle hold on the aftermarket parts channels in the U.S. it makes it really difficult to source out the best parts possible as a consumer. The places we buy our parts from do not have a retail side to them at all, they are all strictly wholesale.
As far as brand they are private label, and not available for purchase in normal retail outlets. We are going to sell the filters we use under our parts page in the weeks to come.
The part number is #15208 AA60
Justin
I just had my ’05 Legacy serviced at your shop today. Thanks for the great work. Is this why the published oil level in the owners manual is less than it was in my former ’98 Outback?
Great explanation about the oil filters. There are 4 Outbacks in our family. Recently I researched K&N oil filters for the Outbacks as I had read that they produced a quality product. I was surpised to see different listings for the years ’00, ’01, ’04 (all 2.5L engines). Here are the specs”
’00 ’01 ’04
Height 76mm 73mm 87mm
Outside dia 80mm 68mm 80mm
relievf valve ?? 11-17 11-17
drainback valve no yes yes
Also ’01 3L engine, takes the same filter as ’04.
If bigger is better, I am comtemplating using the largest filter which is the listing for the ’04, on all the cars. What do you think?
Dear Justin
Do you have any recommendation as to what brand an model number I could pick up at an autoparts store?
Thanks for your time
Colton
#15208 AA60 Please let me know when this filter will be available, I like the fact that you take PAYPAL, Thanks and keep up the good work.
Justin,
I am under the impression that for the 3.6R 2010 OB I should use the black filter number 15208AA031. Does that sound correct? Thanks
Hello Dan,
Yes that sounds correct, Subaru has Always used a good filter on the H6 for fear of premature timing chain and component wear.
Justin
If you look at the specs for the LGT turbo oil filter on say, Purolator or Mobil 1′s web site, with a little digging, you will find that Honda/Acura V6′s use a filter with the same thread, same pressure relief psi, and same diameter, but longer, i.e. bigger. I am still digging for an even longer one.
[...] [...]
[...] a PITA Blue Subaru oil filters Wisdom of Using OEM Oil Filters ONLY OEM Oil Filter: How important? Subaru Service Seattle: Subaru Oil Filters Explained – Seattle Subaru Repair __________________ "Kaylee": 2003 Outback. 93,000 and counting. Formula Shell 5w30, [...]
For those interested, the Union Sangyo is still available and is a very high quality filter. It is the same size as that originally supplied by Subaru up through at least 2006.
FWIW, I’m not sure I buy the thing about a larger diameter filter causing the oil to run hotter due to its proximity to the exhaust header – the oil is already running through an engine block that is at least that hot.
Hi Tom,
So one of the first things you will learn about the Internal combustion engine at an automotive technical college such as UTI or WTI is the single highest point of temperature will be in the Exhaust. Engine oil on a normally aspirated engine is about 220 degrees Fahrenheit. Where as the exhaust will run in temperatures over 500 degrees and the Catalytic converter has to reach 600 degrees to reach its critical point of light off. Subaru moved the primary catalyst closer to the cylinder heads to increase the catalyst function. By locating the Catalytic converter closer to the cylinder heads where the exhaust is just leaving the combustion chamber an is at its peak temperature they have in fact decreased the likely hood that the converter will cool down due to a rich fuel mixture while climbing a hill, it has also shortened the time that it takes for the Catalytic converter to reach the light off point so the Catalyst can effectively happen earlier in the drive cycle. The oil filter on a Subaru sits just adjacent to the right side header pipe, and since mid 2005 the catalytic converter was placed just below this rather than post right side drive axle. The oil filter was decreased in size to accommodate the change in Catalytic convector location and higher exhaust temperatures maintained closer to the oil filter location than previous on the older design (up to 2005). You would have a situation where the oil filter would pick up the temperature being radiated from the exhaust on 3 sides of the oil filter rather than just one side as before, the oil flowing though the oil filter would thew the hot spot in the oil system. The flash point of old motor oil can be as low as 400 degrees as its diluted with fuel from the combustion process.
We have in fact conducted tests and the oil temperature climbs as much as 50 degrees with the oil filter ” touching” the exhaust system.
To try and further explain to you, the cylinder liners in the engine have oil and coolant flowing around it, the oil is one third of your engines cooling system. The idea is to keep the liner and block temperature closer to 212 to 220 degrees and “maintain” that temperature. If the oil or engine coolant is allowed to reach temperatures above the normal range major engine damage can and will occur. The explosions that happen in the combustion chamber create a lot of temperature, at higher rpms and under load temperatures can well exceed 1000 degrees, if you don’t’ buy it install a Pyrometer and go see for your self. What keeps the whole thing from melting down is temperature control.
I am sure you meant no disrespect in the “I don’t buy it” statement, but you know what? It comes across like somehow you think you know more about a profession I have spent my entire working career in there is a lot more to it than you may realize and it starts with some sort of formal education to be a professional.
The best thing about facts are:
They are true whether you “buy them or not”
Justin
Recognizing the very limited life of Subaru oil filters, if good quality synthetic oil is used, does it make sense to change the filter every 3,000 miles and to change the oil every 6,000 miles? Or does the oil need to be drained before removing the filter?
[...] at allwheeldriveauto has a good article on the differences in subaru oil filters over the years. Subaru Service Seattle: Subaru Oil Filters Explained – Seattle Subaru Repair He also has a good picture of that six star cut open next to one that looks like a dealer 12A. [...]
We found that the best filter to use on Subarus is the one specified for the 2009+ Mazda RX-8. It is 100% compatible with the Subaru thread pitch and has both a better filtration media spec and larger oil capacity by several ounces.
The older style large Subaru filters are still available from Blank as well, but the filter media spec is actually inferior to the new Subaru filter. The filter media area is larger so it has more capacity for dirt and will last longer, but the new smaller filter does a better job of filtering when new.
51334
3.194″ height
3.252″ diameter
0.45 quarts based on exterior dimensions, but probably only holds closer to 0.40 quarts
Beta 2 test: 50% of >=22 micron particles catpured 1st pass
Beta 20 test: 95% of >=40 micron particles captured 1st pass
Standard OEM size for older 4-cylinder and all 6-cylinders; won’t fit most newer 4-cylinders due to updated exhaust system
Has more oil capacity than 51365
OK filtration.
51365
2.577″ height
2.685 diameter
0.25 quarts based on exterior dimesions but probably only holds closer to 0.20 quarts
Beta 2 test: 50% of >=15 micron particles catpured 1st pass
Beta 20 test: 95% of >=22 micron particles captured 1st pass
Standard size for newer 4-cylinders.
Good filtration.
51356/57356
3.402″ height
2.685″ diameter
0.33 quarts based on dimensions, but probably holds closer to 0.25 quarts
Beta 2 test: 50% of >=6 micron particles catpured 1st pass
Beta 20 test: 95% of >=19 micron particles captured 1st pass
Not a standard size for Subaru, but should fit all 4-cylinders and 6 cylinders. Installation may be a little more difficult on 6-cylinder due to the length.
Best filtration.
It is actually unwise for a repair shop to ever use a filter that isn’t specifically listed as the correct filter for the given vehicle, if something were to come up the shop could be on the line for thousands and thousands of dollars worth of mechanical engine repairs and no recourse as the wrong filter as per application in cataloging was used.
The H6 also requires an anti drain back valve and I don’t see that specified in your specs, with out it the timing chain and guides will suffer greatly.
I do sincerely appreciate the effort you have put in, but would caution that sticking to the O.E. type filter offered by Six star is a better way to go, as its specified for the Subaru.
Thanks
Justin
Hi Justin,
I understand your position, and that’s probably the best advice for a shop to give.
However, all those Wix filters, especially the one listed for Mazda, exceed the Subaru OEM specs in every category. They all have the anti-drain-back valve (even though they are 100% useless on 4-cylinder and of limited utility on the H6 where the filter is horizontal.)
Just because Wix neglected to mention the Subaru as a compatible vehicle on one of their filters wouldn’t change implications for warranty. For example, for Subaru to deny powertrain warranty claims simply because you used a different filter would violate Magnuson-Moss. If the filter fails due to manufacturing defect, Wix would still have to cover the warranty claim. There is nothing special about the Subaru engine that would make it incompatible with some other filter. That’s why there are SAE design specs for filters. And these filters fit the bill.
Like oil brand, it probably doesn’t matter which one you use as long as it meets the specs. Most important is just doing the maintenance regularly.
Cheers,
Dan
Dan,
I don’t really want to be drawn into an argument but do want to provide you with some life experiences.
Oil filters have part numbers, if you use a non specified part number you are assuming the risk not WIX or any other company for that matter.
I have been involved in several situations where a part that wasn’t specified for the application was installed and there is NO recourse what so ever, what many do not understand about the Magnuson-Moss act is that it is up to YOU to prove the part did not cause failure, in many cases the aftermarket parts vendor will assist you in this if you are going up against an OE who claimed an aftermarket filter caused an engine failure for example. If Subaru says NO warranty you are the one who has to fight, not Subaru, until you get a court date and ruling in your favor. If you think any company will go to bat for you when a non specified part was used, I am not saying aftermarket VS OE I am saying a part that is not listed for the application was used, I am sorry to say this but I have never seen or heard of such a thing and feel it is much to risky when there are plenty of good options listed for the application by other vendors.
Justin
If you uses a part not specified for the vehicle you and you alone are on the hook for any issues. I can argue this point for days and weeks with you and it probably wont matter you have your own belief system.
I work in the industry and have for longer than I care to comment. I have been an expert witness in court many times on both sides of warranty issues back in the 90′s when this was common. I have seen rulings handed out by judges and seen cases not even be allowed to be heard based on application errors.
If you feel this passionately about the WIX filter, I suggest you call WIX and have them add that part number to the compatibility chart for your engine and until you have the backing of the manufacture understand its your opinion only regardless of where or not you feel you have data to back up the claim.
By the way if you use an oil filter on a H6 and it doesn’t have a anti drain back valve you will buy timing chain guides, the anti drain back valve is not of limited utility just because the filter isn’t mounted like the current era H4 engines.
Justin
Hi Justin,
Thanks for all the valuable info. and your dedication to the Subaru public!
I have been using the Purolator Pure One filter in my 2000 Legacy OB, since it seems to be most like the O.E. equipment that Subaru used to carry for my vehicle. Do you have any thoughts about this filter? While not the most widely distributied, I am usally able to find them with a little digging around. I wish someone would do an analysis of the various brands in comparison to the O.E. filter. Fortunately I haven’t had to try it, but Purolator does offer a ‘in case of failure’ warranty.
Thanks,
-Mal.
Hi Mal,
Purolator used to make the replacement filter for the H4 engines up until the Turbo came out in the 2002 Impreza WRX and Subaru dropped the larger filter from stock.
The factory Subaru filter made by Purolator had a o-ring type seal VS the one you are buying the last time I checked still had a Square cut seal.
Justin
P.S. I don’t know if it makes any difference, but I have been using 20/50 dino oil and changing my oil 4 times a year (non turbo model, no snow here in S. Calif.).
subaru sti 2004…
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