Originally Posted by Gebo
What criteria do you use in making the switch? Is it merely miles on the car or how old the car is?
I did it in the old F-150 before the rebuild when it was leaking and had low oil pressure. I'd run 15w-40 in the summer, and in our winters, which are long and cold enough, I ran MaxLife 5w-30. It did the job of keeping the leaks to a minimum (no top off oil over the OCI) and the oil pressure was close enough, over an ILSAC 5w-30. MaxLife wasn't ILSAC rated at the time. I tried Mobil 2000 5w-30 up here, another high mileage option, ILSAC rated, though, and it didn't do as well for my situation.