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Oil filter size

988 Views 6 Replies 6 Participants Last post by  571888
I just assumed maintenance of our 2019 Outback and did my first oil and filter change on this vehicle yesterday using Castrol EDGE HIGH Mileage full synthetic 0W-20 oil. I was surprised that the new Castrol CAS7317 filter I used was significantly larger than the old Valvoline V0-106 filter, that I believe was installed by some quick-change artist like Jiffy Lube. (Please see photo.) I have not observed such assize difference previously working on a small number of other vehicles. Does this mean the Valvoline filter could not have been "correct" for this vehicle? All I really know is it did not leak.

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· Super Moderator
2008 OB Limited 2.5i, Portland OR USA
10,358 Posts
According to Valvoline's website, the VO-106 is the proper filter if you have the H4 2.5 (hint - fill out your profile, please!). However, this is a part number consolidated from the VO-113 once the latter's stock is depleted.
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It's not uncommon to see different can sizes, and it depends upon how much filter media is used. You can probably check out the VO-113 specs at their website to see if it matches the Castrol. And yes, of course the filter faces are going to match; that's a given. It's got to be right or it won't hold back oil pressure. But this alone doesn't necessarily guarantee that it meets the manufacturer's specs.

I'd say you've already done the best thing you could do here, which is to start doing this very routine maintenance yourself. There have been many stories posted here by members about quick change places messing things up, cross threading drain plugs, draining the wrong fluid, etc. Don't sweat whether or not you had one oil change interval without the best filter available being used; in the long run it's not going to make or break anything. People get hundreds of thousands of miles on their Subaru engines with ordinary maintenance, no tricks or mirrors involved, just keep the oil and filters serviced regularly.

And - welcome to the forum! Please do an introductory post here.

· Registered
2012 OB , 2017 Impreza
4,841 Posts
There is a long sorted history regarding Subaru engine oil-filters.

Back when the filters were installed underneath the engine... the physically larger filters would place the filter-can within 1/2 inch of exhaust plumbing. This resulted in the oil getting heated by the exhaust system. Hence, Subaru changed to physically smaller filters which solved that problem (but now there was less filter-media and the filters needed to be changed 1/2 way thru each oil change.)

There are some folks who point to the filter-specification regarding overpressure valve opening. From this perspective, Subaru oil-filters are very unique in the auto-industry. There are not many filters on the market which meet the same overpressure specification as the Subaru filters.

The overpressure valve ONLY comes into play when oil is cold (thick) and cannot pass thru the filter-media fast enough... the valve opens to allow oil to get to the engine (BUT THE OIL IS NOT FILTERED) This condition may NEVER occur for most cars unless you live in VERY cold climate and over-rev cold engine.

Of-course, when the oil filter is mounted upside-down ON TOP of the engine, then the anit-drainback valve within the filter becomes an important consideration. Lest the oil may drain out of the filter when engine is parked. This causes 'dry' startups which can, over time, destroy bearings. (The engine is starved for oil for several seconds EVERY time the engine is started)

To more-specifically answer your question... as a general rule, a physically larger filter allows for more filter media within the can. This is a GOOD thing.

In the end there are MANY considerations regarding oil-filters besides "does it fit"
  • Overpressure valve
  • Anti-drainback valve
  • filter meda micron-size
For some folks, they feel that filters are cheep considering the cost of the engine. Those folks ONLY use Subaru-branded filters.

For other folks, they feel it is more important to CHANGE the oil/filter often than to spend extra on more expensive items.

Your car - your choice 😁

· Registered
2019 Outback 2.5L U5 Limited+M/R+ES+NAVI
2 Posts
Discussion Starter · #5 ·
Thanks for your replies. I did enter vehicle info (2019 Outback 2.5L U5 Limited+M/R+ES+NAVI) in my profile before posting this question but when I didn't find it when I returned to the site. Obviously, I did something wrong. I think it's there now as I see it under my name in the left column.

I've done some work on Volvos over the years, including oil changes. Currently trying to reinstall a steering rack after replacing the leaking hydraulic lines. I will post something in the Newbie forum.

· Premium Member
2020 Onyx
19,449 Posts
There are other oil filters that specify a high bypass pressure, and sometimes the manufacturer provides a TSB explaining why. In the case of Subaru, our oil pumps are exceptionally high volume and they are positive displacement pumps, so the higher the RPM the more it will flow in a nearly linear relationship.

Someone else did a study of oi filter bypass using an electrical connection that would turn on a light whenever the bypass valve opened, but it was not on a Subaru - but the principles are the same. It did open at cold start or high RPM and as the filter gets used, over time the bypass filter opens for a longer period of time, since a used oil filter doesn't flow oil as well as a new one (the pores in the filtering media get partially blocked and pressure differential across the media increases).

(link is russian use Google Translate)

So I don't recommend the use of a low bypass pressure oil filter.

Here's a post about different manufacturers using high bypass: The magical/mystical 23.2psi oil filter bypass spec.

· Banned
150 Posts
Just grab the Mazda N3R1-14-302 Tokyo Roki filter that has the same specs (and larger media filter) for half the price of even the cheapo Subaru filter (if they were even still available) and be done with it. Last time I checked my local Mazda dealer had that filter for $7.50
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