Synthetic & Mineral Oil Mixing

[Billz]

My son accidentally added a quart of 5W30 Pennzoil Platinum Total Synthetic oil to his car which has regular oil already. Is this bad and how bad and should I change the oil now?

 

[Pablo]

Not a bad thing at all. Don't sweat it.

 

[ourfamo4]

No worries at all, he just added a little extra protection.

 

[Johnny]

No harm, no foul.

 

[webfors]

He just improved the oil that was in there by a factor of 1/(# of quarts the car takes).

PP is compatible with all oils, synthetic or mineral.

 

[mechtech2]

If he had to add a full qt., it is using lot of oil and he wasted his money on the synthetic.
But it will do no harm, and is technically marginally better.

 

[chet2]

web is right, oil was just improved...he might want to buy a jug of PP and really treat the engine next time