API service rating mix
Postmaster
Joined: Mar 2001
Posts: 4,968
Likes: 3
From: So Cal
Use at least the rating for the engine that is called out in the manual. for an 80s engine the L or J would work. Technically oils should be mixable and meet spec for the lowest rated oil in the mix.
A newer engine may require the latest spec which I think is L or higher(?)
It is better not to mix grades but in a pinch it will work.
Some of us even prefer not to change or mix grades, brands or weights, but that may be an extreme.
BTW my opinion is based upon reading, not being an expert. If an expert steps in, better to take their advice.
Good Luck,
Jim Henderson
A newer engine may require the latest spec which I think is L or higher(?)
It is better not to mix grades but in a pinch it will work.
Some of us even prefer not to change or mix grades, brands or weights, but that may be an extreme.
BTW my opinion is based upon reading, not being an expert. If an expert steps in, better to take their advice.
Good Luck,
Jim Henderson
Post Fiend
Joined: Jan 2000
Posts: 5,860
Likes: 4
From: Metro Detroit (Redford)
SL is current, but I thought SJ was not all that old, maybe late 90s. I believe the SF is something like '88 and older (Accel 10w40 SF sells for 74 cents a quart at Walmart
). Jim is right, it is better not to mix grades, though usually you can get away with it. Right now I have a witches' brew in my crankcase. It is a long story, but I have 5w30, 20w50, 10w40, Synthetic 10w40, Rislone, and Valvoline Maxlife Engine Protector in there. Whew. Anyway, next change is straight 10w40, all the same brand, and no additives.
). Jim is right, it is better not to mix grades, though usually you can get away with it. Right now I have a witches' brew in my crankcase. It is a long story, but I have 5w30, 20w50, 10w40, Synthetic 10w40, Rislone, and Valvoline Maxlife Engine Protector in there. Whew. Anyway, next change is straight 10w40, all the same brand, and no additives.
