I have been chasing oil leaks on this car for several years and about 6 months ago I decided they had to be fixed. The leaked oil was a combination of engine oil and gearbox oil. I have replaced / reset:
The crank seal (leaking following replacement of timing chain)
The cam seal (probably not necessary)
Both gearbox output flange seals (major leak)
Engine cover seal (minor leaks reset twice)
EGR valve (minor leak but very dirty)
Injection harness (minor leak, repaired with engine silicone)
Vac pump hose (appeared very wet but can't think how if it is sucking?)
There is wetness on the output from the turbo but I think that is just an O ring and is something I can live with until the next round of repairs.
After all of that the car was sat there dripping oil on the drive yesterday morning from the front LH side of the engine / cylinder head (that's RH rear to most of us). To say I'd had enough is an understatement......
After reviewing Trump damage to my savings I decided a trip to the local Merc dealer was not in order just yet and got the car up on ramps.
Step 1 clean up:
Step 2 splash talc over cylinder head (smells nice)
Step 3 idle for 10 minutes:
There goes that stud again, I'm still suspicious about it but if I now blow the oil off it stays dry.
Step 4 idle for 10 minutes
Unfortunately I blew most of the talc off but there is still enough to see that the engine cover is not leaking. Look just to the left of the exhaust manifold stud though.
Step 5 idle for 10 minutes
It's up there on the left somewhere.
Step 6 Investigate.
It could be the engine cover seal again but it appears dry and I couldn't see any oil between the cover and tandem pump. Not dismissed but unlikely, get the mirror and inspection lamp out:
Look at the joint between the tandem pump and cylinder head; I suspect that is most likely it with the engine cover seal to be investigated with the pump off.
Just noticed this:
The replacement EGR valve, if that is oil from the diaphragm vent then the valve seal is shot.
It least I'm now smiling about it.