Pennzoil 0w40 ok in Jeep Liberty?

Jan 18, 2003
Dallas, TX
That doesn't really refute what I was saying; I was saying that 30 weight is what it's engineered for, and running 40 doesn't buy you anything tangible versus 30, so why bother? It's not likely to hurt anything, but nor is it likely to help. And if it did, how would you know?

It's all voodoo and Kentucky windage when it comes to going outside the manufacturer's recommended viscosity. Feel free, but outside of controlled fleet tests, there's no real way to measure whether it's better or worse to do so.