A plan to knock out my 3+ Oil leaks. But will it Work?
 

My 1980 300cd gives itself a nice oil undercoating for winter. However, the leaks are numerous and it's time for me to try and seal them. I can see oil leaks from three places, the valve cover gasket, from the vacuum pump gasket or lack thereof, and there's a break in the oil pan gasket. Since I'm due for an oil change anyway, I want to fix as many of these as possible. I know, when you plug one leak there will be another somewhere, etc.

1. A valve adjustment and new valve cover gasket should solve leak 1.

2. There is a small amount of oil getting into my air filter. This is probably from the leak from around the vacuum pump. I would rebuild the pump with a kit, and put a new gasket in place. I'll check my chassis number as to which kit to buy, but I think post 1979's all have the same pump.

3. Take off the oil pan and replace the oil sep. check valve, which is a valve that is apparently used in the vacuum pump a few times, and is included in vacuum pump rebuild kits, and a new oil pan gasket.

Does this sound like a good plan of attack? Also, I should buy a "vacuum pump rebuild kit" for the pump and a "vacuum valve repair kit" for the oil sep. valve in the oil pan? Which rebuild kit is the one to use, and is there a better place to get the oil separator valve?

Sounds like you have a good plan.
Can't help with the vac pump, sorry.

IIRC the small amount of oil in the air filter might be normal, especially if you car has lots of miles on it. I forget the exact reason but some oil ends up in the air cleaner rather than dumping it on the ground. So if its just a tiny amount that one might not be a problem.

I think I have the same 3 main oil leaks on my '83 240D. Let us know how this works out. I won't be doing mine until spring and its always nice to have somebody else go first ;)

When I bought the car, oil wasn't getting in the air filter, it's a more recent development. It's not a lot, though, sort of a mist. I don't want that oil to get into the vacuum system, I'll have an oil leak under the seats or something and I'll have to replace everything vacuum. Also it appears there is no gasket at all on the vacuum pump for some reason, or the one that's there is degraded and covered in oil. I think the oil in the air filter might the the oil separator valve failure, it's worth it to replace anyway when the oil pan is off.

Take the oil in the air filter as the classic symptom of your vacuum failing and follow your original plan... when it really gives way and you are out on the road it is really hard to stop the car.