Hello,
I'm new to this board and I'm looking for a little advice.

I just picked up two Mercedes. One's a 1977 300D sedan and the other is a 1981 300TD wagon. The 77 300D has an oil leak, a big oil leak . It's coming from the rear of the engine down near where the rear main crankshaft seal would be on a car. Are there other places it could or would be leaking on this car? I know most cars have problematic areas and was wondering if this model has the same with respect to this leak. I looked through the factory repair manual that came with the car and there seems to be two ball bearings that get smashed(?)/forced into the ends of the oil gallery holes? Do these leak normally? Do I need to remove the engine to replace the rear main seal or is it just matter of removing the oil pan and rear main cap like on a Chevy? I'll post some pictures of the cars. The green 300D is in really nice shape other than this oil leak and the wagon has no problems other than normal aging type stuff.

Thanks, Lance



The 300D's engine:

Get a mirror if you have to and examine the rear of the engine block. Oil just might be running down there from a poor valve pan seal.
Unfortunatly the engine has to be removed to deal with a rear seal on the 123 models.

Yes sir, That's what it was the valve cover gasket. I'll buy the part tomorrow. An easy fix compared to what my imagination was dreaming up. Thanks

I'm new to your forums here do you folks have a what it's worth category? I'm kind of curious what these two cars are worth?

Lance

You might just have taken a flying leap into quicksand. Value seems to be influenced by everything including but not limited to the phase of the moon. Exceptional examples demand a premium though.
Just in my opinion prices are all over the place. Rusty ones are the lowest usually. Reading some ebay vendors listings can prove educational.
According to them the one I paid five hundred for is worth perhaps 5-7 thousand. One I paid 3000 for is worth 1500 maybe. One I paid a thousand for perhaps a thousand or a little more. Another I paid a thousand for maybe three. I suspect I will never really know until I want to sell and locate a buyer.
Creative writing also abounds on ebay. True low milage examples are not that common. Even depends on where you reside in the country it appears. Just my opinions though.
I should add there is a value added to the owner simply by being able to do many proceedures on them yourself . The tremendous support plus reasonable cost and availability of parts in general. These older 123s are kind of the end of an era. If possible I would hang on to one good one. As time goes by they will become very scarce.

Yikes! How often do these rear seals go bad?

Not too often. Some last a month even. Actually no way to really predict but many,many years usually. Most of my 25-30 year old examples may have the original seals for all I know and not leaking yet. There is always tomorrow though.

This is true for the top half of the seal, but I believe the bottom half can be replaced without removing the engine. I may be completely off base but I think the bottom half is more likely to fail due to the fact that gravity is pulling the seal down on the top half of the seal, holding it tight to the crank, but it's pulling it away from the crank on the bottom.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

This was the leak. WAY easier than if it had been the rear main



A little purple power degreaser and the pressure washer and it's good as new under the car

I was browsing through the factory manual last night and it talked about only having to "lift" the engine to get access to the rear main. I've never done either pull the engine to change it or the way the factory manual directed. Regardless mine was a valve cover leak so I didn't have to do either