What is the best oil to buy from autozone, pep boys, etc?

Originally Posted by cheshirecat

From what I understand, the Mobil1 5w-30 is not a true synthetic anymore. Also, oil analyses have shows that the VQ doesn't like it as much as other brands. Strangely, it's very similar to Royal Purple as far as the tests go.

That being said, you most likely won't be able to tell any difference either in the operation or the longevity of the engine as long as you change your oil and filter according to the maintenance schedule.