M120 crankcase ventilation

[amgbenz]

Rear main seal is leaking on my 2000 SL600. Dealer thinks that the engine may not be breathing/venting. My local dealer is 100 miles away and the car is not drivable.

The car will not leak a drop idling, but when you race up the engine, oil starts dripping from the rear center of engine.

Does anybody know what I need to check to make sure the crankcase has proper ventilation?

Thanks,

Al