There seems to be some confusion in the eyes of the general public as to what they can run in thier new vehicles. I am relatively positive that a MAJOR lawsuit from many years ago between oil company's and auto manufactures concluded that it was illegal for the manufacturer to "require" that a certain brand of oil be ran in an engine. Only minimum specs for an oil to meet could be required, such as, but not limited to, the API rating of an oil. A friend today bought a brand new ford diesel, and was told that if he ran schaeffers in it they would not honor the warranty on his motor. I am pretty positive that they are not legally allowed to do that, or probably even say that, but he believes it, along with countless others, and I am without physical proof to convince them otherwise. I'm no lawyer and have no clue where to even start looking for that kind of paperwork. So if anyone on here has any knowledge on the subject to share, or links they can post with printable legal documents on the issue, that would sure help me out. I am SOOOOO tired of hearing "well I run (fill in the OEM) oil because it's under warranty and I have to."