The Stovebolt Site Forums The Shop Area Engine Shop OIL

Any harm in mixing multi grade oils when doing a oil change? Example 3qts. of 20/50 mixed with 2qts. of 5/30. Just trying to use up what I have laying around in the garage.
TIA.

I've done it often with no difficulty, but if you're putting 5-30 in a stovebolt engine, I'd question the wisdom of doing that. Stovebolts don't like water-thin oil.
Jerry

I'd agree with Jerry also Brian. I've been running Rotella-T
15W 40 in my engine from the get go. Even used it for the break
in after a complete engine shop engine rebuild. I carry 15lbs
on the road and about 6-7lbs at idle.
As many opinions on oil as there are people that use it.

dg

I've been running 15w40 in my 49 216 since I got it running again (approx. 15k miles ago) and it avg's 12/13 psi cold at speed and around 7/8 psi warmed up at speed. Idle is around psi 5 or so.
That's warm weather pressures.
With colder weather it'll register 15 psi cold but will still settle don to around 7/8 psi when warmed up, just takes longer to warm up.

re. mixing oil. I mix in 20w50 (when I find it on sale)over the summer and get a psi or two higher but stay w/15w40 over the winter. My 216 leaks out just about every sealed orifice when running so I mix oils on the fly (always Rotella T) and theres no telling what the actual "weight" is (it's some combination of 15w40/20w50) The 216 likes whatever the concoction is and so far hasn't let me down.

Ditto on Jerry and Denny
Dave