Oil question

[Man of Steel]

A guy at Advance Auto told me that if I should not mix synthetic with dino. He told me its okay to switch from dino to synthetic but if you would want to go back to dino you have to do a engine flush. One thing I didn't ask him is if what he says is true why do the make synthetic blend? He is full of it or is he correct?? Thanks.

[prathman]

Quote, originally posted by Man of Steel »He is full of it or is he correct?? My vote is for the former. Anyway, with an engine oil change very little of the old oil is left in the engine. Just the film that sticks to the various engine parts. It's not like an automatic transmission or even a coolant change where draining the old still leaves a substantial amount behind. And as you point out, many oils are blends of different types.

[keithvibe]

full of it... i switch back and forth in my wifes car all the time...

[Sublimewind]

Quote, originally posted by keithvibe »full of it... i switch back and forth in my wifes car all the time... +1You shouldn't mix BRANDS/weights, because the various packages in the formulation (it's not 100% oil BTW) might not be compadible... Oil is a very touchy subject for some, but, over all, for our semi-"low performance" engines, it's not that critical.. Now, if you were running FI, it would be a completely different subject, because oil breakdown can be caused by mixing oils..

[Kamikaze]

You don't have to flush it... you just have to drain it and replace the filter...you just shouldn't mix if adding oil.