There is a product on the market that I have had good luck with. I beleive it's made by Prestone, called Sealer. This is used for external oil or water leaks. It comes in a small spray can and NAPA, Auto Zone usually have it. It works and I use it on my 25 year old Chev Blazer from time to time. What surpises me most is the fact that I read all the problems people have with their MB's, when they are known for requiring little or no maintenace. Thats been my experience with my 200K, 97, C280. Really, I have'nt spend a dime on it other than the usual oil/filter/tires & battery. I consider it basically a low maintenace car that will only suffer if abused, as all cars will. Good luck.