quote:Originally posted by Tim Vipond:AMSOIL doesn't believe in paying GM and others money and putting the time in to get on 100's of manufacturers lists. No manufacture requires an oil to be on the list in order to keep warranties intact. If GM required an oil on their list to be used, GM would have to provide it for free. Money and time wasted. But AMSOIL offers oils that meet GM's specs, and never had a warranty issue.quote:Originally posted by Big Bear:
Tim, how come Amsoil isn't on GM's approved list? Even there API certified XL Series? Even some of these small no name companies made it.
The list of approved oils is a list of oils that meet all the specs. Nothing more or less.
They can, and do, require whatever oil you use to meet said specs for warranty coverage.
I haven't seen any owners manual that says "Use whatever oil and or weight you want."