I'm in the middle of changing my water pump on my 89 190 w/2.6. Since I have so many parts off the car, I thought it would be a good time to try and track down an oil leak that runs down the front center of the oil pan and also ends up on the trans cooling hoses and bottom of the oil pan. The leak seems to happen when the car is running not while just sitting. There doesn't seem to be a leak at the top timing cover seal so I was wondering if it is the front crank seal? Has any one replaced their front crank seal and how would I go about doing this? Should I just redo the timing cover seal and the crank seal since I have most of the front of the engine apart? Thanks in advance.

most likely the front cover at top. Here's the DIY for diagnosis/repair:
http://www.peachparts.com/Wikka/M103TimingCoverReseal

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89 300te 222,222
92 300e 190,000

Yes if you can its a good idea. Like you were thinking the more things you get out of the way the less likely you will ever have to go back in there again.

Also don't forget to change the small o-ring that seals the long bolt that holds the braket from the p/s pump to the fan beering braket. That always sends the oil down the front of the pan when it leaks.

The front crankshaft pulley requires 221 ft lbs of torque and a torque wrench that goes that high - which makes it not a simple DIY job.

Thank you for the replies. I did clean the engine as best I could with those spry can engine cleaners to try and see where the leak was coming from. I wasn't completly sure it was from the top timing cover. I was thinking to replace the seal as a precaution.
The O-ring that is mentioned, is this the bolt that holds the Y-shaped bracket for the PS pump and the long bolt that mounts the belt tensioner? I didn't remove the Y-shaped bracket from the front of the engine only loosen it. I didn't notice an O-ring. Is it between the bracket and the engine or between the head of the bolt and the bracket?
Maybe I will have to pass on the front crank seal as I don't have a torque wrench. I don't need more problems caused by not having things tightened correctly.
Do you think if it were the crank seal the oil would be on the back of the harmonic balancer? It does seem to be dry. It's just the oil down the front of the oil pan that is really noticeable after the car has been running. Do you think it could be the oil pan gasket or would that leak all the time? Thanks again for your help.

Well I finised up changing my water pump along with trans cooling hoses, valve cover gasket, new radiator hoses and resealing the uper timing cover along with a new cam shaft seal per r_p_ryan. Thanks, very helpful writeup. I get everything back together and start the car. Two minutes after, the oil is running down the front of oil pan. I am back to thinking the front crank seal IS bad and needs replacement. Do I need any special tools other than a torque wrench and a puller for the harmonic balancer or other parts other than the front seal? How is the seal removed from the cover and is there any special tools for removal or installing the new seal? Please let me know if anyone has done this repair on a 2.6 engine. Thanks in advance.

Well I decided to bite the bullet and start taking things apart again to get to the front crank seal. I needed to remove the radiator, shroud, belt, water pump pulley, the belt tensioner and dampener, belt, the bracket mount for the fan, and the pulley mounted on the harmonic balancer to be able to have a straight pull on the balancer. After doing some digging on this site, I decided to try loosening the large bolt by fastening a 2 foot breaker bar w/ 27mm socket to the frame and bumping the starter. I must admit I was a little worried about breaking something but after the third bump the bolt spun right out. I have a harmonic balancer puller I rented from Autozone and it worked perfectly. I read alot about two locating pins that need to be aligned during reassembly but my balancer is keyed on my crank shaft. After I got the balancer off I could see the fresh oil leaking down the front of the block. I was able to pry the seal out with a screwdriver using a piece of wood between the block and the screwdriver to protect the block from damage.
The next bit of bad news was that the bearing thats mounted in the housing that the fan pulley and clutch mount to is shot.
Does any one know if this bearing is replaceable or do I need to buy the whole assembly? Fastlane here I come!!
Does anyone have any info for tightening the bolt for the balancer? I read about how to loosen the bolt but I don't remember seeing any tricks for tightening it. I was thinking about using some loctite as insurance to keep the bolt from loosening up. Hopefully I have the car back on the road by next weekend....

As far as the fan clutch bearing bracket is concerned you are looking at around a hundred bucks. for your model.

http://***************/catalog/lookup_parts.cfm?SubcategoryID=6817&VehicleID=1192676&CFID=299551&CFToken=79250914

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190e 2.6 1990. 300,000 KM
C230 K 2000, 130,000 KM

I had mine off a few months ago ( M103). I don't know if this is approved, but I wedged a piece of aluminum angle-iron into the area at the back of the engine, on the bottom, and in front of the torque converter. There are some bolts in the flywheel that the aluminum interfaces.

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89 300te 222,222
92 300e 190,000

Sorry I didn't respond back in a timley manor I've been very busy latley.

That o-ring for the bolt is located inside the lower rite bolt hole thats on the fan beering bracket you will be replacing, and you will notice that bolt is a bit larger diameter by the head.

I also removed the bolt by bumping the starter.

Thanks theairboy. I saw the O-ring you mentioned earlier when I removed the fan bracket. Do you know what size the O-ring is or where you can pick one up at? Also, how did you retighten the balancer? I was thinking of using some Loctite thread lock to make sure the bolt doesn't come loose. Thanks again everyone for the tips.