A must read about mixing oils

[Bror Jace]

LarryL, that was great ... especially the parts about going by what your mechanic and the counter person at your local auto parts store say.

--- Bror Jace

 

[LarryL]

I always say, when your talking oil, you go straight to the source.

 

[Matt89]

LarryL, I agree. You'd get farther talking to the oil well (source) than the clerk!

 

[thunderchild]

I mix a 5 quart jug of ST 10w-30 synthetic with 1 quart of M1 T&S 5w-40. I need 6 quarts and don't want to bust open a 5 qt. just to get 1 qt out of it. I use the 1 qt M1 since it is about gone anyway.

 

[Alamogunr]

Can single weight oil be mixed with multi? I bought a 5 qt jug of 5W-30 and reached for a 6th qt but didn't look real close. Got home and when I opened it to lube the filter gasket, it was 30W. Can it be mixed with 5W-30 on the next change? (Since I didn't know, I went back to the store and got a qt of 5W-30) Next change should be in warm weather. Yeah! I know, its always warm here compared to some of you.

 

[Bryanccfshr]

Yes, it will simply lower the VI of the oil in the sump.

 

[TallPaul]

And I would guess the base oil will thicken, but the 100C viscosity will remain about the same.