A buddy of mine has a nice 93 lincoln mark8 with 83k miles. He didn't know better, so he was using valvoline oil for the first 75k then he switched to valvoline maxlife for the past few oil changes. The good thing is that the oil has been changed regularly (3-5k), the bad thing is that the engine is very varnished, and I bet it has some sludge in it. I was talking to him about oil and he asked what he should do. I recommended that he do an auto-rx treatment to get the gunk out of the motor, then switch to a good quality dino (havoline or motorcraft brand) He uses a 10w30 weight oil in the car year round. I also told him that I would use mobil 1 10w30 in a motor like that after the auto-rx treatment, and it will help to clean up the motor alot. the motor is the 4.6L DOHC v8 (basically a cobra motor minus a few parts inside) I'm getting him on the right track. Anyone have any additions to my recommendations?