The wife is interested in buying a 2020 ~ 2021 Subaru with the 2.5L Boxer engine . Oil recommendation is synthetic 0W20 , for those with experience with the late model 2.5L Boxer engines - what 0W20 (or other grade synthetic oil) did you find to be your favorite oil for this engine ? ...* Also looks like from 2019 on this engine became direct injection - hopefully Subaru has a good method to curtail intake valve deposits in the 2.5L Boxer DI engines . Thanks for replies !
Late Model Subaru 2.5L Boxer Engine Oil Choice ?
- Thread starter ChrisD46
- Start date
What is the OCI in the OM?
Any OTC 0w-20 will do; I believe the OCI was shortened years ago and a coworker does his about 6K miles. (2016 IIRC) They are using Valvoline @ the Subaru dealer.
Any OTC 0w-20 will do; I believe the OCI was shortened years ago and a coworker does his about 6K miles. (2016 IIRC) They are using Valvoline @ the Subaru dealer.
They don't. The dealership will gladly sell you a walnut blasting service on the intake valves! Plenty of threads on NASIOC about it.
As far as oil choice it doesn't really matter but oil filter choice definitely does. Subaru runs a high bypass spec on the filter so you're pretty limited on filter choices. OEM is always a good option.
A new to my brother Scooby 2.5 was just eating his lunch between oil and filter changes
My classic EJ-22 thrived on a 40 weight. (95 model year)
His much more modern 2.5 boxer took much better to a 30 grade synthetic in a pennzoil fluid.
Not too much heavier than the 20 grade previously specified, but he's been happier with going up one step.
Mind: he's a heavy driver as a medical responder.
Otherwise if you're not chewing through a sump to the tune of 1k miles/ quart...faggeddabouddut.
EDIT: Try using CRC intake and turbo cleaner every second oil change before oil change is required. It's not a 100% guarantee to keep intake and valve cleanliness, but it's been really great on the one GDI motor I look after. (A GM, not even related)
My classic EJ-22 thrived on a 40 weight. (95 model year)
His much more modern 2.5 boxer took much better to a 30 grade synthetic in a pennzoil fluid.
Not too much heavier than the 20 grade previously specified, but he's been happier with going up one step.
Mind: he's a heavy driver as a medical responder.
Otherwise if you're not chewing through a sump to the tune of 1k miles/ quart...faggeddabouddut.
EDIT: Try using CRC intake and turbo cleaner every second oil change before oil change is required. It's not a 100% guarantee to keep intake and valve cleanliness, but it's been really great on the one GDI motor I look after. (A GM, not even related)
Last edited:
Superbuick96
Site Donor 2023
Started off using M1 0w-20 for the first 3oil changes' of my 2018 2.5 Forester , but switched to QSUD 0w-20 for the last 2 changes. No consumption with either oil, I change it out every 6 months. 18 was the last year without DI through.
Long history here with Subaru from 1995 to the present. I've had really good luck with Valvoline synthetics in the 0W-20 flavor in the 2013+ Subaru engines. However, the last two oil changes on my wife's 2020 Legacy have been with QSUD 0W20. No consumption at all at 5k oci. As stated when buying filters stick to one that meets the Subaru 22-23 lbs bypass pressure. I used Wix/Napa 57055/7055 filters and they seem to be outstanding. OEM would be fine as well, but I like the construction of the Wix a little better.
I used the NAPA 0W20 synthetic bought on sale. I do not think the engine is tough on oil. It does spec a synthetic 0W20. Buy Subaru OEM filters on Amazon by the 6 pack. Or NAPA Platinum on sale.
if a 5or10W30 meets the spec that would be my choice for sure in your hot climate + being DI , good luck + as a major recall just came out, common with many newer vehicles though! AWD will just add complications + is NOT a plus where you live, IMO many other sedans are a better choice + can be cheeper!!
I can't speak for the 20-21 but the 18 Legacy I have specifies 6k/6mo OCI and has a sump of 5.1qts. I believe the newer ones have a smaller sump. I am using am OEM filter and M1 0W-20 EP. My wife has been driving it and said it "feels" smoother than with the Subaru branded oil but I can't prove that at all. Feels the same to me the little I drive it.
I just leased a 2021 Subaru crosstrek limited with the 2.5L engine.I’m letting the dealer do the first oil change with my penzoil platinum 0w20 then I will do the oil changes with Valvoline advanced protection 0w20 for factory 6k oil change interval.
I used M1 0w20 for the first 40,000 miles with excellent results. Last 15,000 have been using ST 0w20 (love the 12 quart box) and again results excellent. Never had a bit of oil consumption in any of my previous 6 Subies. Agree with others about the need to use properly spec-ed oil filter because of the pressure valve - I use Fram UG from Amazon. OCI's at 5,000 (even tho Suby suggests 6,000. BTW, I think OEM filter is produced by Fram with the paper end caps. Proceed with caution. The UG is much better constructed and worth the xtra money, I think.
Past EJ's needed 30 or even 40 grade to live; the FB25 has been a mixed bag with oil consumption and TCT issues. The last two Foresters we traded had major consumption issues and we did consumption tests on the last one which was a FB25. Overall had eight Subaru's (lost count) and at least four with the troublesome 2.5 litre. The newer FB have longer stroke smaller bore. and has less real world power but is less noisy form a piston racket standpoint. Have not owned a newer D.I. FB25 but in the past these engines needed some 30 grade to keep them quiet when they got hot. I would recommend adding 1 or 2 qts of same brand 5W30 to a sump of 0W20 - not over 5 qts total - or just run a 5W20 which tends to run closer to the 30 grade margin.
After break-in, say 15-20k, if the car gets some longer highway jaunts on a weekly basis, a 8-9K mile OCI are showing better results than the ridiculous 6K OCI. - which was lowered due to owners NOT checking their oil level and running out between oil changes!
Caution! do NOT overfill boxer engines!'
I have multiple OCI posted on BITOG running long OCI on our Crosstrek showing better results than the unit average with short OCI. Data talks, baloney walks. - Ken
After break-in, say 15-20k, if the car gets some longer highway jaunts on a weekly basis, a 8-9K mile OCI are showing better results than the ridiculous 6K OCI. - which was lowered due to owners NOT checking their oil level and running out between oil changes!
Caution! do NOT overfill boxer engines!'
I have multiple OCI posted on BITOG running long OCI on our Crosstrek showing better results than the unit average with short OCI. Data talks, baloney walks. - Ken
*Thanks for the replies : If the wife buys the new Outback then I'll use a synthetic oil with low ash and low VII's to combat IV deposits (Valvoline Advanced) in 0W20 . I like Fram Ultra oil filters - hopefully they are designed with the high bypass pressure Subaru specs ?
Could it possibly be that the fram ultra media flows better and therefore has a lower pressure delta for a given flow?
I mean, we don't really know what RPM 13 psi or 27 psi would occur across the filter. 27 psi seems tremendously high, as if it would never open under normal operation.
Last edited:
Low bypass will not be an issue with NA engine that do not have the oil feed banjo fitting mesh screens that had been clogging on the EJ255/257 turbo engines. We have been using Fram Ultra on Subaru engines with good results and QUIETER starts,
yeah. I had a 2007 Legacy GT Spec.B and remember this being an issue. I ran the Wix/Napa filters.
Similar threads
