Persistent oil leak - camshaft seal - 300E
 

Hey guys -

I'm at my wit's end. I have a persistent oil leak in my '89 300E M103 engine at the camshaft seal. It is definitely leaking at the camshaft seal - not the head gasket. Here's what I have done thus far:

1. Relaced all rubber seals and gaskets - including camshaft seal, valve cover seal, etc. Still leaks.
2. Replaced the aluminum timing chain cover piece (where the camshaft seal actually sits) and another new camshaft gasket. The aluminum piece was sealed with that Mercedes sealant recommended for this piece. My mechanic was specific about this and he did a very neat job sealing this. Still leaks.

My mechanic normally does excellent work and they did the second job mentioned above basically for free since they didn't fix the leak the first time around. I'm really stumped. Any ideas why it is still leaking? The leak is minor, but adds up over time. Not to mention having oil all over the front of the engine and inside the distributor cap! :(

Thanks!

That oil just keeps looking for a way out.... Three months after I did the camshaft seal on my 103, it started leaking again.
I get the feeling that resealing the 103 is a little like that kid with the finger in the dam.

A new cam seal should not leak unless:

1) It is not seated correctly.
2) The cam has worn the head (no bearings) surface down enough that the cam is lower and thus does not line up with the center of the seal. It would leak at the top.

I replaced a seal that I installed with another when I did not seat it correctly.

I also noticed that the cam was closer to the bottom of the seal than the top. But not enough that the top leaked.