Boy it seems a lot of you guys have crummy MB dealers in your area!!!
Both in the Dallas Texas and Columbus Ohio areas I have had great experiences. If for some reason I didn't, I got the service manager at the dealer involved and all was corrected quickly
As my car is a diesel they only fill it halfway between the two marks on the dipstick.
It seems to me that before I would allow a dealer to do something that would harm my car, I would at a minimum question the practice. If they continued I would involve the regional MB rep. If he doesn't correct it ,then at least all parties have been duly informed before you take legal action..... :-)

Warren
1992 300SD 118K
Columbus Ohio

I am aware these are very old posts however the same issue just happened to me. Had 30k service two days ago at the dealer and today decided to check the oil only to find out that it is overfilled.

Now they had previously told me i had a head gasket leak, prior to service i knew i had some sort of leak just not where it may be.

Does running the engine w/ overfilled oil accentuate the existing leak?

I have spoken to the service rep and he will address this an another issue soon.

Yeah, this is an old thread.

Running the engine overfilled can cause the crankshaft to churn up the oil and cause cavitation. I don't think it would really accentuate a headgasket leak, though. However, I would remove the excess oil.

I once pulled almost 9 quarts of oil out of an M104 during an oil change which had the previous oil change performed by the dealer. The "max" level on the dipstick is 7.4 quarts.

Just a longshot, but have you checked your garage/driveway surface with a good level? A floor that looks level to the eye (or at least to my eye) can still be sloped or uneven enough to cause dipstick reading errors of this magnitude.

Thanks, dealer indeed overfilled engine oil, i have been told it was removed.. i guess i should check again just to be sure.