Just had my head gasket replaced ('95 E320), but after driving for a couple days, there's still an oil leak. Much smaller than before, but it will leave a 1" puddle overnight.

I cleaned things up underneath, and waited for the drip. It appears to be leaking from the engine/transmission junction - it drips from the seam, and I can't find any evidence of oil higher up. It will also continue to drip if the car sits for a couple days. So...rear main seal?

If so, any idea how many hours this should take a competent mechanic to replace?

Thanks,

Bill

Before you tear into this job, have you modified your oil charge from the owner's manual recommendation? There was a tsb some time ago directing owners to refill the oil to 7 liters - not the 7.5 liters indicated in the manual. This was because 7.5 liters was too tough on the main seal. I believe 7 liters is about midway between the FILL and ADD marks on the dipstick.

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95 E320 Cabriolet, 169K

I did read about the TSB here, and no - I haven't verified if it's filled too full. Since the car's new to me, I have no clue if the last few changes took the TSB into account or not.

However, I was under the impression that if the seal was damaged due to overfilling, the damage was already done, no? Or could reducing the oil level (assuming it's too high) stop the leak?

Thanks,

Bill

I don't know. I can only imagine that the damage is not permanent. With the lower charge, excessive pressure on the seal is relieved.

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95 E320 Cabriolet, 169K

I had oil coming out from there too, but it turned out to be the oil cap seal on my oil filter. Oil is a funnny thing when it leaks cause it has a tendency to get everywhere and with the wind under the hood and etc.. it is hard to tell where it is coming from. I have a 96 SL320 and nearly every seal was replaced in it due to the overfill, including the rear main. The front main was easy compared to the rear but I got it done. I would remove the front cover and see if there is oil in there, does the converter have oil on it? Make absolutely sure it is coming from there, like I said, I have had oil end up here and it was coming from somewhere else.
Brian

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Brian W. Heitman

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The ideal oil fill for 104 eng is at 1/2 way on dip stick mark at operating temp.
That will eliminate seal leaks if the seals are still good..

Digging this one up from the archives...

The leak remains, and it's not anything mentioned above (oil cap seal, oil level.) The mechanic who did my head gasket believes it is the rear main seal, but quoted $1500 to repair. Quite frankly, I'm just not interested in spending that kind of cash on this. I still make it between oil changes without adding any, and a drip pan results in a crude fix.

However, I've now got access to a lift, and some spare time. How tough of a job is this? Any special tools required? Could two guys drop/replace the tranny by hand with the car on a lift, or would a tranny jack be advisable?

I've pulled/dropped engines and trannys in the past, but it's been 20+ years. I can turn a wrench and don't mind getting dirty, but this is a big step up in my MB maintenance skill set...