Has anyone heard of any documented evidence or even credible rumors that someone running 0W20 or 5W20 has had engine damage or increased wear? Reason I ask, with all the oil change shops changing oil, and misinformed customers, there are an awful lot of people asking about it because a shop put the wrong grade oil in (xW20 instead of xW30). But I haven't found anyone who has had a shop do it and it actually hurt an engine. Plenty of stories of places like Walmart/Jiffy Lube, etc who did it to a customer for a long time and they never knew until they looked closely at the records and found out much later. The more I study it, and it is a deep topic, very deep, I would be surprised it would hurt. Unless it is an engine that is either already in sad shape or a just a sloppy built engine. Anyone?