My 1995 Jeep Cherokee at work has been retired. It left with 226,060 miles on the odometer and God knows how many on the engine with all the idling it did in it's 10 year run. It had 15w40 dino changed at 6 month intervals with Fram filters for 9 of it's 10 years. The last year it had Amsoil 15w40 synthetic in it and went to pasture with it. The engine was the original with no internal work done to it and it also had the original tranny with the original fluid and filter still in it. It did not have any trace of red left in it. Alternator, water pump, radiator, rear axels, springs and shocks and rusted floor boards were replaced and in the end rust was taking over. It averaged 10,000 miles per oil change and used the much maligned Fram extra guard filters. Still no engine problems. In its place came a 2005 Saturn Vue with V6 and awd. It will see Fram filters and what type of motor oil has yet to be determined. At present there are 2 grades of motor oil used. Amsoil 15w40 which is now used only for the diesel part of the fleet and in May of 2005 Amsoil 5w30 ASL was brought in for the gasoline vehicles. They are considering getting 5w-20 for these Vues and for 2005 Ford Focuses that were purchased for the meter readers. It should be interesting to see if this Vue makes it's 10 year run as well as the Jeep did. I'll be retired before it is.