The Ful and Six Star filters are identical to what Subaru used to offer before switching to the Blue Honeywell filter. Bypass valve is exact, not meets o.e., there are some pictures in a post on this site showing the filters cut apart.

I don’t really want to get drug into the type of discussions often found at forums, some of what I read in the link is non factual and I will leave it at that, if you are comfortable with the Wix I am sure it will work just fine for you.

Thanks

Justin

Thank you for the reply. I have a couple of questions on your reply.

(1) According to literature (eg. http://www.subaruoutback.org/forums/104-gen-4-2010-present/41457-sorry-oil-filter-question-again.html), 15208AA12A does have an anti drain back valve. So, blue Subaru filter is similar in construction to 15208AA031, with less filter media. The less filter media may cause less pressure drop and better oil flow at the expense of filtering. That is my concern.

(2) Do you know the bypass valve opening of Full filter that you mentioned? Without that information, I would be not use that filter as almost all aftermarket filters have low bypass valve pressure ratings, which means less filtering and more dirty oil.

(3) Does the full filter have an anti drain back valve similar to 15208AA12A and 15208AA100?

If you say yes I would like to use full filter as an alternative to 15208AA12A, otherwise WIX 57712 is a better alternative.

Thanks,

Priya

As I have stated before, if YOU put something on your car other than what is specified by the Manufacture you are really taking a large risk that is unnecessary.

15208AA031 Has an anti drain back valve your model doesn’t call for as the H6 models have a sideways mounted filter and the anti drain back feature helps limit the potential for un primed engine start ups this is because the timing chain guides will wear out on dry start ups and are quite costly to replace on the H6 models.. Using a filter that is equipped with an Anti Drain back where it isn’t called for could create a problem delivering oil.

I you want to go to a better Oil Filter You can look into the Full brand, its made in Japan and a good choice over the Blue Subaru / Fram filter.

Hope that helps

Justin

I wonder if it is OK to use 15208AA031 filter on EJ25, H4 engine on a 2010 Impreza. The filter fits fine without any issues and I do not think that it is too close to exhaust manifolds. My only concern is whether this filter causes an extra pressure drop due to extra filter material, however, I do not think it could be as the bypass pressure for this filter is also the same as 23PSI. So, I would like your input on using H6 filter on Gen 3 Legacy and 2010 Impreza.

Thanks.

Thank you for your reply. Whenever these types of things come up I always have to factor in the diverse group of Subaru owners, and really just dont want to put anyone in a situation they may not have success dealing with if there was ever an issue.

Thanks for posting, I am always here to help

Justin

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

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

[...]Subaru Service Seattle: Subaru Oil Filters Explained – Seattle Subaru Repair[...]…

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