Front Crank Seal Leak?
In an effort to get the various oil leaks under control on my '84 300D, I pressure-washed the engine and then took it in to an indy mechanic so he could raise the car up and pinpoint the leaks. He verified that the slightly crushed lower pan leaked, as well as the oil filter housing. He also advised that I replace the motor mounts, the tie rod assembly, and the driveshaft support bearing. I undertook replacing the beat up oil pan and the motor mounts with little incident. However, I had a hard time getting the oil pan to stop leaking around the gasket. So I took it back in to the shop to have the remaining items done (support bearing and tie rod), but the mechanic said "I didn't see this before, but it looks like your front seal is leaking." Aghast, I responded "no, I think that's from the main belt pulley slinging oil up from the leaking oil pan and gasket..." He disagreed and stuck with his front seal diagnosis.
Heavy with disappointment, I went home and pondered the implications of such a grim announcement. Then I had an idea. I resolved to tighten the oil pan bolts (which clearly indicated leaking, since oil was pooling inside the hexagonal holes of the bolt heads), then take it to the car wash and clean it up real good. I did this, and now it looks like the leak has stopped, with no indication of oil weeping down the front of the engine, which it would do if the front seal were blown. I have not concluded without a doubt that the seal is NOT leaking, but I think the mechanic may have been hasty in his diagnosis.
This is a long way to ask: how likely is it that the front seal would leak? The mechanic also warned me against putting 7.9 quarts of oil in the crankcase with each change, and suggested 7 quarts instead. He seemed to hint that the overfilling may have something to do with a blown seal (which is now a dubious claim, given my little "experiment").
1995 E300 Diesel (Die Blau Frau)