oil leak and others on a 1990 300SL
 

The check engine oil light came on on my mom's 300SL the other day. When I popped the hood, the plastice cover under the engine bay looked pretty greasy. It seemed to be concentrated on the drivers side of the engine bay. The leak looks like it might be comming from a tube that led from the bottom of the engine to the bottom of the radiator, maybe an oil cooler line? Anyways how can i diagnose and fix this problem. I noticed the car also needed a new hood pad and a new tube that goes from the intake to the air filter assembly. I'm also having trouble with the soft top. Thanks for any help.

btw, I love the car but what what mercedes thinking about when they decided to but all that plastic under the car?