Yes, the bad valve seals are a common problem. They need to be replaced. Most try to rehone and replace the oil rings without much luck. I tore down my '94 SL2, and have these observations and opinions: The worn valve seals are only part of the problem, when I looked at the bores of the cylinders, they looked like they had been poorly honed at the factory with a contaminated or broken hone, clearly a quality control problem. There was a deep groove cut in the same crosshatch pattern as the other honing.I took it to a machine shop and had it rebored to remove the factory honing altogether. Since I have seen a number of postings from people who have only replaced the rings with mediocre results, I wonder if this problem is widespread. After breakin it uses a miniscule amount of oil.
Larry