Oil Filler Cap/Neck on E320

[Ian B]

There’s a slight oil leak coming from the oil filler cap/filler neck of my 1998 E320 (W210 V6). Although it is not causing a lot of oil loss, it runs down the side of the engine and needs wiping off every few days. My question is; how do I remove the filler neck from the top of the engine to check the seal? I can turn the filler neck by about 20degrees and I’ve tried pulling it up whilst turning, but to no avail. Is there something holding it in place from within?

Thanks a lot for any help…

[Parrot of Doom]

Are you certain the seal isn't on the cap itself? I can't quite remember but I think mine is, it certainly is on the coolant cap anyway. I have the OM606 engine btw (3.0 TD)

Also, when you run the engine with the cap off, does it spit oil out? Might be worth checking for a blocked breather as well. On mine, the breather is here:



Its the pipe that runs from the clyinder head bottom right, to the air intake just before the turbo. It pulls out with no tools.

Edited by Parrot of Doom on Monday 9th October 13:35

[Ian B]

Parrot of Doom said:

Are you certain the seal isn't on the cap itself?...

Might be worth checking for a blocked breather as well.

Thanks for that, P Of D.
There is a seal on the cap which seems OK, but I now need to check the seal between the plastic filler neck (that the cap fits onto) and the engine. I presume there will be an O-ring in there. How do I remove the filler neck?

Good point about the blocked breather, I'll try running it with no cap and see what happens.

[Ian B]

Had a go at running the engine for a while with no filler cap on and no oil was chucked out.

I also had a look for a breather pipe similar to the one in your photo but it is quite a different layout and there was nothing similar on my V6 that I could see. Anybody got an illustration/photo of the breather system for an E320 W210 V6?