I was thinking of changing from 5w30 to 10w30, and when I got to autozone I saw 15w50. Can anyone think of a reason why this could be bad for the car? I know gas mileage may be slightly affected, but it should protect the car a little better, right?

 

i am running 15w50 b/c my 10w30 oil analysis came back with a slightly higher than normal Lead count (bearings wear). My I do have a TT setup. I'd go with 5w30 for an n/a car, unless your oil analysis comes back bad.

Gurgen