Subaru Forester Owners Forum banner
1 - 20 of 87 Posts

·
Registered
2019 Forester
Joined
·
19 Posts
Discussion Starter · #1 ·
We have a lot of synthetic 10w30 oil left from the previous car. Can I use it for our new 1219 Foresters?
Thanks
 

·
Registered
2018 Forester XT Touring HT-CVT
Joined
·
615 Posts
The manual says you can use 5W-30 if 0W-20 is not available. 10W-30 could theoretically work in your area then as long as you don't plan to drive anywhere that goes below lets say 40 F. The 30 rating is okay and the 10W wouldn't really matter much if you don't drive in cold weather.

That being said...don't expect the same mileage as with 0W-20 but hey it's your car and your motor. Alternatively, you could just try to sell the batch of oil to someone local.
 

·
Registered
2017 Forester
Joined
·
312 Posts
Call me crazy but how much oil could you possibly have that is worth not following manufacturers requirement. I’ll guess it’s less than $100 if that.
It’s your money and your $30k+ car so you get to make the call.
Just remember, other opinions that say it’s ok to use your leftover oil don’t have to deal with any possible issues.
 

·
Registered
2017 Forester 2.5i CVT
Joined
·
200 Posts
The issue that concerns me is not the 10w-30 if in summer as the same engine in Japan and Europe is rated for 0-20, 5-30 or 10-30, the 0-20 requirement here is US CAFE nonsense. My concern is that for your warranty you have to save the receipts for the oil you bought as part documentation you did this. Do you still have these? Now I use 5w-30 myself. Or buy some new synthetic 5-30 to use later in the car, put your 10-30 in now as long as it is summer, have those new receipts to prove to the dealer "I did the oil change." if you need them. And receipt for the filter too.
Of course no absolute guarantee they would not claim any non 0w-20 is a warranty violation on the non-turbo engine like mine. Your choice.
 

·
Registered
2021 Forester Limited
Joined
·
2,535 Posts
I look at it this way...can you? Sure you can based on your climate. Should you? Absolutely not. As others have stated, you will void your warranty should you have an issue and not worth the risk IMPO.
 

·
Registered
2013/14 2.5i-L CVT
Joined
·
935 Posts
Why not put in only ~1 quart of the 10w-30 and top up with 0w-20 at each oil change until you've used up your stock.
 

·
Registered
1999 A/T - 235,000 mi. WA state
Joined
·
890 Posts
Suggest: put your 10w-30 oil on Craigslist for cheap, and empty out your garage at the same time.

Call me crazy but how much oil could you possibly have that is worth not following manufacturers requirement. I’ll guess it’s less than $100 if that.
It’s your money and your $30k+ car so you get to make the call.
Another old time saying is seeing someone step over dollars to pick up dimes.
 

·
Premium Member
2019 Crosstrek 2018 Forester XT
Joined
·
14,791 Posts
Not unless you want to potentially void your engine warranty.
Not gonna happen. Magnuson-Moss Warranty Act states among other things that the vehicle defect has to be the result of customer abuse. And Subaru must PROVE that it resulted in damage.

Using 30wt oil isn't on the radar screen. When your engine is hot (200+F) 30 wt oil is 10 cSt. and 20 wt. is 8 cSt. At less than 175F or lower 20 wt oil is greater than 10 cSt. So you are voiding your warranty every time you start up your vehicle? Nope.
 

·
Registered
2019 Forester Sport CVT
Joined
·
504 Posts
Will 29% greater viscosity harm the Forester 2.5 engine at operating temperature? Doubtful.

Does the old oil meet the minimum standard for the GDI 2.5 Subaru engine? SN and GF-5?

What happens when one uses a thicker oil? Reduced horsepower, that's what. That's from the guys that analyze what happens in motorcycle engines with the urge to go from 40 to 50 weight oil.
 

·
Registered
Sahuarita, AZ 2018 Forester Limited
Joined
·
2,816 Posts
I believe that willfully ignoring the manufacturer's (and warranty grantor's) oil recommendation constitutes gross negligence on the part of the owner. Besides, does one really want an engine warranty claim to turn into a Magnuson-Moss Warranty Act legal matter, perhaps with expenses, if Subaru denies the claim?
 

·
Registered
2015 Forester 2.5i Premium 6-speed manual
Joined
·
177 Posts
I have some old Navy Distillate that might not be what Subaru wants in the engines they designed, but it does not explicitly say in the owners manual that I cannot use it, and many believe that I should. I should ignore the owners manual because I know that Navy Distillate works, so do others and they believe I should. Besides, the Magnuson-Moss Warranty Act will protect me from Subaru declining to honor their warranty if something should go horribly wrong because others told me so. After all Subaru should know that Navy Distillate works too, because some believe they should.
 

·
Registered
Sahuarita, AZ 2018 Forester Limited
Joined
·
2,816 Posts
Does the old oil meet the minimum standard for the GDI 2.5 Subaru engine? SN and GF-5?
Maybe it does and maybe it doesn't, but a good point and another consideration for the OP to evaluate before using any leftover oil.
 
1 - 20 of 87 Posts
Top