I posted my question on this site and then I looked at what other people had said. I decided that it needed new n\valve stem seals becuase the car was burning oil. I then found a post which said that it took $50 of parts and 2 1/2 hours labor insted of a $400-2000 job, it cost me $280. I feel like a genius and that these repair shops are trying to rip consumers off. I lost all confidence in the alldata website. My 420sel is no longer burning oil!