Best oil weight?
Just use 0W-40 Mobil 1 for gas or 5W-40 Mobil 1 for gas or diesel. They work for any temperatures.

I believe that Mobil 1 was originally developed as a factory installed oil for Porsche's. It evolved as the oil recommended for European high performance engines.
BTW, I live in Arizona and dealers put in 5W-40 Mobil 1. It's a low sulfur version of 0W-40 and works for both diesels and gasoline engines.



