1998 S600 M120 oil leak
 

I have a oil leak on the M120,that I located on top of the oil pan,drivers side,its dripping with the engine off,constantly,however,I cannot seem to define the part that is leaking from,looks like some sort of sensor with a cover and ,removing the 10 mm bolt that holds the cover on,it has 2 small pistons with O rings inside,I dont really know how to define the part and what is it for...I took a picture of the part with the drop of oil on it,it drips right on the control arm,drivers side,see the pic.Thank you in advance for any helpful input.

Hard to tell from your picture, but sounds like these two pistons with o-rings are at the bottom of the oil filter housing? These are probably the plugs to cover holes for the oil cooler hoses. Your car probably doesn't have oil cooler? The o-rings p/n 016 997 61 48

Hi,

Digging up an old post, because i now have the exact same symptoms as thread starter on my M120.

Anyone know more about this? Can someone confirm that this is oil cooler hose block cover? And is it just to unscrew cover, change o-rings and put it back? I assume oil must be drained first?

Thanks for any input :)

I can confirm that the blocking cover is easy to remove, no need to drain oil, but expect some cups of oil coming out when removing it so be prepared.

Replace the two o-rings, and reinstall the cover. A bit tricky to reach from under the car, but totally doable. This fixed the oil leak from my engine. Cheap and easy fix :)