Does anyone have any actual tests that "prove" that thinner oil runs cooler?
mechtech2 said:That is my experience too. My oil temps with 10W30 are 5-10 degrees higher that with 5W20 under the same general conditions.
Agreed. There's a notable difference between an xw-30 and an xw-40 in my Audi when driven under the same conditions, with the lighter weight being cooler, of course.