I have an 82 240D which I've owned two years. I change the oil often and it also annoys me that it gets dirty so soon. I'm not aware of two "O" rings that should be replaced, just the one large one at the oil filter. My 240D has 287,000 miles on it but the engine was rebuilt 40,000 miles ago. It runs great and starts very fast without smoking or missing, but it uses plenty of oil, a quart every 800 miles at best. Where are those two "O" rings?