At the Texas State Fair in Dallas this weekend, while checking out all the cool cars at the car show, I noticed that the 3.8L Buick V6 equipped cars (Buick V6 is used in all GM brands except Caddie) all had "Use 10W30" printed on their caps. The Chevy 3.1 V6 equipped (again...not just used in Chevys) cars still called for 5W30. The rest had a little book symbol with an i next to it indicating, "Check the manual" which I assume means that the manual recommends different grades based on temp or some other special recommendation. Buick V6 is one of those engines that has had problems with front main bearing wear. I wonder if that might be the reason. Any thoughts/comments?