This was from Amsoil's FAQ page.
quote:Flow obviously is important so running a thick 50wt. in a tight engine, as Bob and others have stated, isn't always the answer. Engines rarely fail due to oils, but I bet in high performance cars, it could be different. This is just more proof that thicker is not better and that flow plays a huge role. I still think Steve Bergin could be right and that viscosity has little to do with wear. With modern engines being so well built, I really think the 20wt oils will do fine. [ August 22, 2003, 11:37 PM: Message edited by: buster ]
Federal Mogul Corporation, a manufacturer of engine bearings, pistons, connecting rods and other engine parts, studied over 7,000 case histories of bearing distress and engine failure and never found engine oil to be the cause of a failure. Dirt, the number one cause of engine failure, was found to be responsible for 43.4% of failures, and insufficient lubrication, the second most common cause of failure, was responsible for 16.6% of failures. Insufficient lubrication is the general term used when not enough oil gets through to the engine to lubricate it (lack of oil volume).