2008 Subaru Outback oil recommendation

[K20SiGUY]

Hello all,

Recently my girlfriend had a deer hit her old plastic Saturn which left it without a front quarter panel or door panel. After a few days of searching we found a 2008 Subaru Outback manual with 50,000 miles in excellent condition.

I've been doing some research on here since I dont know much regarding the flat fours in them. So far ive figured out that we either need to buy a genuine subaru oil filter, or go to napa and get the correct one spec'd for the high PSI bypass valve setting.

Her Outback is the NA 2.5l, I know it calls for 5w30, locally I can get any M1, or PP in any weight. I was thinking of maybe running M1 0w40 in it since its what I run in my Si and its been a great oil. I was also thinking of maybe running Rotella T6 since I can get that locally too. It seems like there are many opinions out there regarding these flat fours and id like to hear some options on what I should buy.

 

[Bandito440]

5w-30 PU is what I'd go with, although if you want to use xw-40 for the sake of simplicity, it won't hurt anything.

 

[901Memphis]

Suburu naturally aspirated engines have proven easy on oil. They will run on conventional or synthetic 5w30, 5w40, and just about anything in between. I wouldn't hesitate to use the M1 0w40 since you already stock it but make sure you get your money worth that's an extended interval oil, should be good to 7500 easy.

 

[05LGTLtd]

Originally Posted By: Bandito440
5w-30 PU is what I'd go with, although if you want to use xw-40 for the sake of simplicity, it won't hurt anything.


+1

In a NA 2.5, I'd lean heavily toward the M1 0w-40 if you want to go xw-40. Or castrol 0w-40 if you can get a good price. T6 is great and all, but probably a bit thicker than needed in comparison to BC and M1 for this application.

Enjoy your Outback!

 

[gpshumway]

The Napa/Wix filter has the correct BPV setting, but small filtration area and its maximum flow spec (9-11 gpm) is lower than the pump output (12 gpm @ 5,000 RPM). I'd personally stick with the OEM filter.

As to oil, N/A Subaru EJ engines are pretty easy on oil, and not picky. Any synthetic 5w30 will do great, as will M1 0w40. RT6 will work fine as well, but it's substantially thicker than required by an N/A EJ. It's a favorite of the turbo EJ crowd, but totally unnecessary in a non-turbo car. M1 0w40 is as thick as I would go.

 

[bvance554]

I never knew Subaru's had an oil filter issue. I've always used Purolator. Yes any oil will work. I use Mobil Super 5k 5w-30. Its a great engine and will outlast the rest of the vehicle. You should pay more attention to the MT and differentials. You'll want to change that out soon. The combo MT/front diff is the weak link in this vehicle.

 

[K20SiGUY]

Thanks for the input guys. Ill stick with the stock oil filter and probably go with PP in 5w30 or M1 0w40.

Regarding the diff and transmission. I know that the dealership changed the diff fluid before she purchased it, but I'm not sure about the manual tranny fluid. Does anyone happen to know the recommended intervals at which both of those should be changed?

 

[gpshumway]

They don't really have an oil filter "issue" per-se, it's just that Subaru specifies a much higher than typical bypass valve opening pressure. If you've been using the old Purolator 14459, that was an OEM Subaru filter at one point, and has the correct ~23psi BPV.

I used to think it was a big deal, many have said the BPV pressure is due to Subaru's very high volume oil pump. Well that 12 gpm pump it turns out flows about the same as the pump in my Honda R18 and less than in a Honda K20. Hondas use filters with ~10 psi bypass which are otherwise very similar to the Subaru filtiers, right down to being manufactured by the same company (Fram).

I've personally stopped worrying about the BPV, though I still worry about filtration area. The disassembled Tokyo Roki Subaru filters have lots of media. For aftermarket filters I'll be using either the Purolator Synthetic or Fram Ultra once my stock of Tokyo Rokis is depleted.

 

[gpshumway]

D'oh, simultaneous post.

Trans fluid intervals are highly variable. For "normal" service there's no interval mentioned at all, so presumably >100k Mi. For "severe" service the interval is 15,000 mi.

I change mine with Subaru Extra-S every 30,000, I do occasional towing and track driving. If you're not towing or other heavy usage, 60,000 seems a reasonable interval.

 

[Bandito440]

I used plain ol' Valvoline conventional 75w-90 in the transaxle and differential on mine. It shifts the same as it did with Extra-S.

 

[bigjl]

Always used OEM oil filters as they were the same price as anything else I could find, and guaranteed good quality.

In the UK you have a choice of cheap own brand from Halfords, or expensive ones like Zero Sports from Japan and I am sure K&N did one. Not forgetting the pink STi one I seen at a dealer once.

But for value I couldn't beat OEM in this instance.

Good luck with your Outback, one of the nicer looking ones before they made it look like a cross between a Honda Accord and something very ugly.