Hello all! Noticed some oil seeping from the cam adjuster on the M104 while doing the 60 k svc today. Is there a seal for the adjuster or is this leak the cam shaft seal? Any ideas???? Thanks, Dan

What yr/model do you have ??

There was a Benz TSB change on oil level on 104s. If the dip reads past 1/2 full when warm, there will be oil leaks.
The capacity level was changed .

Arthur, thanks for the info, it is a 1991 300sl, does the TSB cover this model??? Thanks, Dan

I will look it up..

Mercedes Dealers:
Technical Service Bulletin : TSB-#00/134 and TSB #18/45
11/94
Effective Immediately:
All 104 engines
Oil capacity reduction:
Oil/Filter capacity reduced from 7.5 ltr to 7.0 ltr.


Changes will be forthcoming in Maintainence Supplement. Change any maintainence manual data until supplement issued. Customers should refrain from topping off past 1/2 dip-stick mark at running temps.

Very strange that 1/2 qt extra could cause leaks. Is there some additional information?

Yes there is .. They state that the TSB was to cure engine oil leaks due to the over capacity of oil.

Ever notice the notorious front U seal on 104s don't leak until the engine oil was topped off or changed?
Ever see the high oil pressure this engine operates at?? [pegged at idle]

Notice many Techs tell there customers to keep the dip at the 1/2 way mark to stop their oil leak complaints ?? It works.

.. and my own thoughts are that this also may have attributed to the famous oil seepage at the right/rear of the head gasket...ever notice nothing else leaked from the head gasket except oil?? [ no water leakage an no compression leaks..pretty unusual for a head gasket leak to be just oil]
..but Benz is not about to admit to that one until they admit to the wire harness that they never had any trouble from..

I'm a new owner of a '95 E320 so I haven't noticed oil leaks relating to oil level.
I just think it's strange that oil level could somehow affect oil pressure, 'specially 1/2 qt.
My 320 does have oil pressure *almost* pegged and idle, but so did my '87 300TD.
I can see how a higher oil level might affect areas that are subject to oil splash, but how does it make the head gasket leak?
There are cases of Benz (and certainly other makers) offering a red herring as to the cause or correction of a fault. It gets the service writer or shop foreman off the hook, if nothing else.

Benz doesn't put put a specific TSB for kicks...
They had oil leaks and their recommendation/cure was oil capacity reduction for that engine.
That is the message directly from Benz.
The head gasket is my own theory, and I just think the oil capacity just aggrevated the situation. The oil channels in the head are not a splash system. They are under pressure. [ except for drains]

Well , I guess I'll drain off some oil. If this doesnt work, is there a seal behind the adjuster or is the camshaft seal the problem?? Thanks, Dan

there is a gasket ..check that the hex head screws are snug...don't over- torque them.

Over-filling the engine oil can cause excessive crankcase pressure, and force leaks. Plain and simple. The leaks won't occur on the pressurized side, though. Valve covers, crankshaft seals, filler caps, etc., are where the leaks will be noticed.

I can remember a few instances when MB "unofficially" recommended reducing engine oil level by about 1/2 quart, but it didn't have anything to do with external leaks. The issue was foaming of the oil in the sump. I remember fixing a few OM602's and 603's that developed valve taps after a highway run. At higher RPM, the turbulence caused by the rotating crankshaft would actually aerate the oil. If the engine was left idling, the valve tap went away after a minute or two. In this case, the oil level reduction fixed the problem.

In the case of the M104 cam adjuster leak, I'd recommend cleaning it thoroughly and watching it closely. Either the sealant between the magnet and the front cylinder head cover has failed, or, the oil is leaking out of the two-pin electrical connector. IMHO, the latter is most likely the problem and the magnet will need to be replaced.

Thanks for all the great input. I'll drain some oil off (it's @ the very top of the range) , clean the magnet and watch it for further leaks. Thanks guys, this forum rocks! Dan