After reading all of these replys, it stikes me as funny that so many people are caught up in the oil hoohaa.. Read the last reply from Williston and that should tell it all. 300,000 on his Volvo using 10w30. according to most his engine should have gave up the ghost 200,000 miles ago. I use 5w 40 rotella syn and have for some time now. No ill effects no warrenty problems, no engine related failures ,just happy motoring.