2018 Subaru Forester 2.5 Touring oil viscosity

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VQLT

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Feb 5, 2018
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302
Location
So. Cal
Just sold our old minivan and purchased a new forester. The minivan spec'd 5w30 (which I have 15 quarts leftover, probably should have given it to they guy who bought the van) The Forester requires (or recommends) 0w-20 unless
you use in hot weather (I'm in So Cal)
several of you might remember this confusing / contradicting info in the owners manual
"0W-20 synthetic oil is the required oil for optimum engine performance and protection. Engine oil viscosity (thickness) affects fuel economy. Oils of lower viscosity provide better fuel economy. However, in hot weather, oil of higher viscosity is required."

Bottom line, can I use 5w30 or should I swap with someone on BITOG
smile.gif
for 0w-20?
 
This is sure to bring out the T vs T crowd.


For warranty purposes I would stay with the 0w20 recommendation. You will hear lots of opinions either way on this.

Know any family or friends that could use the 5w30?
 
Subaru says you "should use synthetic oil" in the Owners Manual. So, if your 5w30 is a full synthetic, go ahead and use it in sunny southern California.
If there was ever a warranty claim challenge, you could point to the Owner's Manual statement in Section 11 to cover your rear end. 5w30 would be fine in that engine. Its really not that much thicker when hot than 0w20, only like 15% greater HTHS, not much.
 
Its a brand new $30000+ car.. go get some pennzoil platinum at walmart send in the rebate and its under 12$/5qt

Also the newer oils are supposely better formulated for GDI.

What brand and type is the 5w30. ie m1/syn or castrol conventional etc.
 
Originally Posted by Rand
Also the newer oils are supposely better formulated for GDI,
Said it was the 2.5L engine, no turbo, no DI. Doesn't care about having SN+ and/or dexos1 Gen2 anti-LSPI oils here.
 
Originally Posted by VQLT
Just sold our old minivan and purchased a new forester. The minivan spec'd 5w30 (which I have 15 quarts leftover, probably should have given it to they guy who bought the van) The Forester requires (or recommends) 0w-20 unless
you use in hot weather (I'm in So Cal)
several of you might remember this confusing / contradicting info in the owners manual
"0W-20 synthetic oil is the required oil for optimum engine performance and protection. Engine oil viscosity (thickness) affects fuel economy. Oils of lower viscosity provide better fuel economy. However, in hot weather, oil of higher viscosity is required."

Bottom line, can I use 5w30 or should I swap with someone on BITOG
smile.gif
for 0w-20?


The OM actually says this?
IIRC the OM of our '17 Forester says no such thing and recommends that only a 0W-20 be used.
The OM of our '09 says that 5w30 is preferred but then goes on to recommend a panoply of grades based upon use and temperature.
If the OM really does say in unambiguous terms that a thicker grade may be required in hot weather, then the 5w30 should be no problem.
Anyway, in the unlikely event of a serious warranty claim involving the engine, there is really no way of knowing what grade you put in the engine and in the event of catastrophic failure, which is what we'd be looking at in the event of a warranty claim, Subaru's only out would be that the oil had never been changed, and that would be obvious whatever grade you used.
 
The bottom of section 11-11 carried over to the top page of 11-12 in the 2018 forester owners manual
(copy and paste directly from the manual)
NOTE
Engine oil viscosity (thickness) affects
fuel economy. Oils of lower viscosity
provide better fuel economy. However,

- CONTINUED -
11-12

in hot weather, oil of higher viscosity is
required to properly lubricate the engine.
 
Very odd wording. Thin oil is required but thick oil is also required? I'd run 5w30 synthetic myself but it's not my car. My aunt's Subaru burns a bit of oil, 2015 Impreza and she uses 0w-20...
 
oil is Valvoline full synthetic high mileage with Max Life. What if I bought a couple quarts of the same oil in 0w20 and mix it with the 5w30 at oil change until all the 5w30 is gone
 
very odd wording indeed. hoping some Subaru expert out there can explain. it does not specify what "hot" weather is or what "higher" viscosity is. I don't see how they could void the warranty if I use pretty much any oil I want (within reason) as long as that language is in the manual
 
Originally Posted by VQLT
oil is Valvoline full synthetic high mileage with Max Life. What if I bought a couple quarts of the same oil in 0w20 and mix it with the 5w30 at oil change until all the 5w30 is gone
Thats a good dexos1 API full synthetic 5w30 there. No problem using it straight in a warm climate. Take the Owner's Manual statements as a reason to follow their hot weather advice.
Originally Posted by VQLT
very odd wording indeed. hoping some Subaru expert out there can explain. it does not specify what "hot" weather is or what "higher" viscosity is. I don't see how they could void the warranty if I use pretty much any oil I want (within reason) as long as that language is in the manual
There've been other threads similar to this, and it "Is what it Is" as they say. The wording stands. The Note says you can use a higher viscosity oil in hot weather, which I guess S. CA has enough of that.

Its actually only 11% difference between HTHS of 0w20 ((3.0-2.7)/2.85 = 11%). Thats not a lot.

I suppose you could use 0w20 in the winter, and 5w30 all other times of the year, that way you'd use it up.
 
Originally Posted by VQLT
very odd wording indeed. hoping some Subaru expert out there can explain. it does not specify what "hot" weather is or what "higher" viscosity is. I don't see how they could void the warranty if I use pretty much any oil I want (within reason) as long as that language is in the manual

I'm curious how you're documenting your oil changes? I've done the first one at the dealer but at $90 all in, its a bit much. I was thinking of buying the oil filter there atleast and keeping those receipts with the mileage written on them. That's what I've done with my tractor but now its out of warranty and I never had an issue.
 
VQLT: Lucky you! Given the revised wording of the 2019 OM, I wouldn't hesitate to run a quality 5w30 weight synthetic oil -- either M1 or Pennzoil would be my choice -- in your 'Roo. Not even a close call.
 
I just took possession of the vehicle and have not completed 1st oil change. When I do, I will just document in the service manual
 
Originally Posted by Hounds
VQLT: Lucky you! Given the revised wording of the 2019 OM, I wouldn't hesitate to run a quality 5w30 weight synthetic oil -- either M1 or Pennzoil would be my choice -- in your 'Roo. Not even a close call.
Revised wordiing? Looks exactly like the 2018 manual. It still give an owner the ability to use a thicker oil in hot weather, over the 0w20 basic stuff. Here is the section from the 2019 Owners Manual

subieoil.webp
 
Noticing the 2018 & 2019 Subaru manuals address the infamous oil consumption issues Subarus have been having. Their weaselly, lawyerly approach to oil consumption is to note all the normal driving conditions (try avoiding any of those in daily life!) that can cause a Subaru to consume oil. Apparently, leave it parked & thats the only way to prevent oil usage.... Also, notice how they worry about someone hurting themselves checking oil! ... Here is the 2019:


subaru11111.webp


subaru2222.webp
 
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