2010 Subaru Outback and filters

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A few of you may have caught some of my oil/filter research and I ended up going with Mobile 1 extended with a royal purple filter. When I changed it, I caught something that had me doing more research...the filter is tiny but the space has plenty of room for a longer filter. The problem is I don't know enough about filters so I searched around and found this:
https://allwheeldriveauto.com/subaru-service-seattle-subaru-oil-filters-explained/
Essentially, with the newer ducting (I have this) or with turbos, a larger/longer filter would be too close to the exhaust pipe and increase the engine temp. The author also mentions that the small filter won't last long due to the size, even synthetic. I can buy this argument but no evidence to really back it up.

So now I'm thinking, drop the oil change interval and/or at least the filter change down to 5k for simple change math to avoid a failing filter. I'll find out if the oil can remain if it dumps too much out...but I'm pretty sure I can go with just the filter. Anyone have any thoughts/recommendation to add...besides doing the test, which I will do at 5k.
 
On my Subaru I have run the tiny oem blue filter, Fram Ultra 6607, the taller Honda blue oem filter, a Fram Ultra 7317 and currently a Napa Gold 7055...

No noticeable difference ...

And the taller filters, like the Napa 7055, still have a good inch of clearance between the filter and the header heat shields. The location is HOT, regardless of filter size. I don't believe oil is inside the filter for long enough to impact oil temps to a measurable degree.

The Napa 7055 is a Subaru specific filter, with the higher by-pass setting like the oem filter uses. I don't believe the RP filter has the higher by-pass setting. Not sure it matters though...
 
Originally Posted By: geeman789
On my Subaru I have run the tiny oem blue filter, Fram Ultra 6607, the taller Honda blue oem filter, a Fram Ultra 7317 and currently a Napa Gold 7055...

No noticeable difference ...

And the taller filters, like the Napa 7055, still have a good inch of clearance between the filter and the header heat shields. The location is HOT, regardless of filter size. I don't believe oil is inside the filter for long enough to impact oil temps to a measurable degree.

The Napa 7055 is a Subaru specific filter, with the higher by-pass setting like the oem filter uses. I don't believe the RP filter has the higher by-pass setting. Not sure it matters though...


Thanks. I've been researching that bypass and you're correct on the RP. Here's a link to what I'm reading now:
http://www.subaruforester.org/vbulletin/f113/subaru-oil-filter-comparison-99130/#post1077639
The mx guide OCI is 7500 which baffles me with that filter...I may try doing the oil analysis a few times if I want to stay or go above 5k. I'll look at that napa.

Also, as far as that exhaust shield...it does well for a 1 hr drive...I should have burnt myself when I changed it this time, but the oil filter was hotter than that shield. Back to research.
 
The "short..." Napa / Wix Subaru spec filter is the 7712... however, having a threaded end bypass valve means it has a very small filter area... one reason why I chose to run the 7055.

As for the OCI, 5000 miles seems reasonable, and simple. Fresh oil and filters never hurt anything...!
 
my thoughts are you should not exceed the manufactured specifications for oil changes and use the factory oem subaru fram filter.
 
I think you made a great decision with the RP filter. Eventually you should try pairing it with a nice 2015 vintage RP oil
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I would just stick with the stock length. That's what the engineers had in mind when they designed it. Just my 2c.
 
I run the WIX/Napa 7055 or 57055 filter with the higher bypass spec on both my older EJ engine as well as the FB. The older EJ are fairly easy on oil so that 7,500 interval is realistic. The FB engines are in the same boat but sipping oil and sending people into a panic reduced the OCI to 6K... mostly so the oil level light would not cause PR issues (OMG top-off oil, [censored]?!?!?!?).

Filter size: If all things are equal, then yes, size can have an impact but comparing size apples to oranges is not useful. For example, "size" is not just the can size,, but rather the media area. You can make a giant filter with few pleats or a tiny filter with many pleats. The "micron" rating can effect capacity as the finer media can both hold more and allow more filtered oil to potentially pass the media as well. With that being said, it is a Subaru... which moves a lot of oil. I would rather have the correct bypass than a bigger filter as if the bypass is 8-11psi, I bet it allows more unfiltered oil pass so the efficiency becomes zero.

FYI, I had two Purolator filter fails on my EJ engine. Otherwise, the WIX/Napa (5)7055 have not had an issue with recommended intervals.
 
Originally Posted By: FutureDoc
I run the WIX/Napa 7055 or 57055 filter with the higher bypass spec on both my older EJ engine as well as the FB. The older EJ are fairly easy on oil so that 7,500 interval is realistic. The FB engines are in the same boat but sipping oil and sending people into a panic reduced the OCI to 6K... mostly so the oil level light would not cause PR issues (OMG top-off oil, [censored]?!?!?!?).

Filter size: If all things are equal, then yes, size can have an impact but comparing size apples to oranges is not useful. For example, "size" is not just the can size,, but rather the media area. You can make a giant filter with few pleats or a tiny filter with many pleats. The "micron" rating can effect capacity as the finer media can both hold more and allow more filtered oil to potentially pass the media as well. With that being said, it is a Subaru... which moves a lot of oil. I would rather have the correct bypass than a bigger filter as if the bypass is 8-11psi, I bet it allows more unfiltered oil pass so the efficiency becomes zero.

FYI, I had two Purolator filter fails on my EJ engine. Otherwise, the WIX/Napa (5)7055 have not had an issue with recommended intervals.


Thank you for the feedback on the Purolator. I'm assuming that was the Synthetic version?
 
Subaru's higher by-pass setting is rumoured to have been put in place because of problems with clogging of the banjo bolt screen on the oil supply for the turbo, obviously on turbo engines only.

These bolts have a fine mesh screen inside, and if they get plugged up, that reduces oil flow to the turbo, and the turbo dies soon after. Any unfiltered oil flowing thru the filter and possibly picking up some filter contaminants ( sludge, debris...) COULD lead to clogging. And Subaru's oil volume may lead to more by-pass events on a filter with a lower by-pass setting.

Some say the higher by-pass setting is of no benefit to non-turbo engines...
 
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Like FutureDoc, I prefer a filter with the proper Subaru bypass spec for our 9-2x. I choose the Fram PH9715 (nearly identical to the OEM Subaru filter, which is made by Fram) and have never had an issue. All the ones I've cut open have looked goid, even those used during winter and for intervals up to 8k miles.
 
Subaru has had a history of high oil movement (rather moving a LOT of volume), before the turbo crazy really hit the brand (in the US) too. I know the EJ22 was the same as the EJ25 and I think the EA engines were up there as well. The EJ22 never had a turbo-ed counterpart I think so why that engine would remain up there other than Subaru mono-spec engine laziness (which did not happen until the late '90s). While there might be some credit about the banjo theory, Subaru was better about their turbos than their NA engines as far as adding redundancy to the design. I do not think it would "trickle" down... it was not Subaru's MO (otherwise they would have figured out/responded to the HG issue faster). I have very little experience with the EAs but I think (via the subaru rumor mill) they could push filters (spec-ed for bypass at the normal 8-12psi) into bypass mode while both warm and idling thus the 20+ bypass was required. Might be worth looking at those aircraft engine folks as I think those models were popular with them.


My "Purofailure" was the P1 on the '99 ej25. One happened around 3700-4200miles and the second happened at 3,000 mostly because I wanted to see if it failed (and yes, it did). Normally my '99 gets the 6mo or 5,000 mile routine (often 6mo as it is the local hauler). So, I change it at Spring/Fall intervals.
 
Originally Posted By: FutureDoc
My "Purofailure" was the P1 on the '99 ej25. One happened around 3700-4200miles and the second happened at 3,000 mostly because I wanted to see if it failed (and yes, it did).


Yep, that large oil flow in the Subarus can certainly induced more delta-p and more stress on the pleats, which surely could contributed to the filter failure.
 
Originally Posted By: ZeeOSix
Originally Posted By: FutureDoc
My "Purofailure" was the P1 on the '99 ej25. One happened around 3700-4200miles and the second happened at 3,000 mostly because I wanted to see if it failed (and yes, it did).


Yep, that large oil flow in the Subarus can certainly induced more delta-p and more stress on the pleats, which surely could contributed to the filter failure.


Shhhhhhhhh.... don't give the tinfoil-wearing purohumpers an excuse...now they will say Subarus are at fault... (despite Purolator specing the filter for my application)
wink.gif
 
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