So my poor e300 has developed a leak. I have not climbed underneath to investigate but it seems to be from the front left (driver's side) of the motor. Our mechanic ( who is an Audi mechanic, but such a good guy I like to take whatever I can to him) says it's an o-ring in something or other and that the o-ring is dirt cheap but the labor is huge. He guessed it was about $500 to fix. Can anyone tell me what this might be that is leaking? Is this common? Can I fix it myself?

Also the oil that is leaking is BLACK, and I mean BLACK. I don't know if that means anything or not.

 

hmm i'm not farmiliar with the diesel but mine had a similar leak.replaced a cover on the front of the engine and gasket- $127.50....although i had more problems going on at the same time check this thred out

https://mbworld.org/forums/e-class-w210/147120-yay-more-car-trouble.html

 

i don't know about the diesel i6, but the gasolinee m104 i6 are known for developing a oil leak over time at the front-left (passenger side). it could be leaking from the timing cover (1-2 hour job) or headgasket/cylinder head (10 hour job). doesn't hurt anything if you can tolerate a few drops on your garage floor.

 

The fact that the oil is black only tells you that it is leaking motor oil and not brake fluid or fuel or ATF, etc. If he said (and meant) O-ring and not a gasket like valve cover or head gasket, it leads me to think that it is some oil line going to the injection pump, since the turbo is on the right side. Be sure that this guy knows this engine well...you don't want to start chasing ghosts. Hard to say though...oil pan gaskets and valve cover should be less than 500, head gasket certainly more...this is interesting. Keep us posted.

 

Yeah - o-ring for sure. Standing over the engine he was looking down between the drivers wheel and the engine. That is when he said it might be this dreaded expensive thing. I had the benz in for something else, and told him just to look at this. When I came back he confirmed it was the o-ring he was thinking of. Said it's around $500... I totally trust him, but like you said, don't want to start chasing ghosts. hmmm. Well I'll keep you updated.