C320 rear crank seal leakage

[Gerry R]

I have a 2004 C320 4matic wagon and for some time the rear engine seal has been leaking and the result was both right side oxygen sensors were ruined. I understand that this is a common problem. Is there a better fix than just replacing the seal holder with the OEM part or a modification that might help? I just spent $1,782 to fix but from what I was told this setup is problamatic.

[Gerry R]

Am I the only one with this problem? Hard to believe, oh well.

[eric242340]

You are not the only person, it is a very common problem and the new parts are modified so once changed it should not happen again. I do not see how it can damage your 02 sensors though.

[Gerry R]

It seems that as oil leaks past the plate it is probably blown back hitting the wires which are quite close by. A really crappy place as it almost assures getting oil on them. And I might add that the amount of oil leakage is very small, I usually go 6-7k miles between changes and it has never been low enough to need to add.

[eric242340]

Originally Posted by Gerry R

It seems that as oil leaks past the plate it is probably blown back hitting the wires which are quite close by. A really crappy place as it almost assures getting oil on them. And I might add that the amount of oil leakage is very small, I usually go 6-7k miles between changes and it has never been low enough to need to add.

Oil on the wires will not damage the sensors, it will interupt the signals but once cleaned off all should work as normal, I think these sensors were only changed to make money for some workshop or they did not know what they were doing.

[Gerry R]

That's what I thought but I had two independant shops tell me they were contaminated and nothing could be done except replace after fixing the seal. The question now becomes how do I find a shop in my area (Portland Oregon) that will be straight and honest with me? One of these shops only works on MB, which is where I had it fixed. I have had dealers do this so I searched out independants.

[eric242340]

Browse through this thread from our sister forum, Benzworld;

http://www.benzworld.org/forums/reco...-repair-shops/