Crankcase oil builds up in these M137 motors right where the intake plastic pipes and the manifold meet. It will drip out of the joint.
There are some known issues with the PCV system on these cars.
If you have warranty or service contract, you might want to use it.
Regards
DR.D

__________________
Dr.Diesel -
Shop Foreman
Master Guild Mercedes-Benz Technician.

Think the dealer is expensive? Do you know how much it costs to train a dealer tech? Or buy the required MB special tools to have on hand?