I used to swear by Mobil 1, but have recently seen a 4 year old 40,000 mile Honda Accord driven by a senior citizen experience worn rod bearings and scuffed cylinder walls (using Mobile 1). Also, my Audi has developed what I'm quite sure is piston slap under certain conditions after 50,000 miles, again using Mobil 1. All new oils that were made to work with catalytic converter equipped cars are crap. We didn't experience these types of problems to such a degree with the
oil used years ago when I was a kid, even beating the hell out of my cars.