Hey people! I was changing the air filter on my '80 240D and when i got the old filter out of there, i noticed it looked sort of a little oily on one side, just a little bit. Then i looked down into the intake manifold and i saw some black liquid what looked a lot like used engine oil, so i am not exactly sure if it was engine oil, but nevertheless, it was some sort of black funk. Do you guys think this is something i need to check out or this is something completely normal? I was thinking maybe some valve was not properly adjusted and when the engine went to compress the fuel, there was a little gap and because of very high compression pressure, some of the fuel mixture may have gotten out of the combustion chamber and into the intake manifold, and that's when i saw it. This is what comes to my mind, but let me know if you can what you think!!!Thanks a bunch!