Warburto:

Checked with my local Benz guru and he had this to say:

Any leak on the oil filter housing will look like a rear seal leak. Things to look at:

Oil cooler line fittings. These are pipe threads, filled with a sealer. The sealer goes bad and they start to leak. Hans takes them out (a huge pain) and re-seals with the addition of a copper washer between the fitting and the housing. Cures leak.

Pressure line to the turbo. Runs from filter housing around the back of the engine to the turbo. Banjo bolt seals on oil filter housing often starts leak by this age, easy cure-- remove bolt, replace washers, re-install bolt. Also looks exactly like a rear seal leak except starts too high.

Oil pressure sending unit leaking.

All will get worse on a long highway trip due to oil temp.

If you do, in fact, have a rear main seal leaking, go to WallyWorld or K-Mart and get some "Engine Restorer" -- trake name -- and add to the oil. Repeat on next oil change. The seal almost always will swell back out enough to stop leaking, and it appears to be permanent. Much cheaper, at any rate, than a new rear seal!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!