C250td Oily air pipes

I'm a bit concerned by how much engine oil there is in the air pipes on my 1998 c250td
There's quite a bit of oil in all of the air pipes from after the air
filter all the way 'round to the intake manifold so I assume it's coming from the engine breather through the oil separator.
I tried cleaning out all of the air pipes and the separator but the oil returned almost immediately.
I did think about buying a new oil seperator but as it's a simple cyclonic system, without any filter or moving parts as far as I can see, I thought a new one might not be any better.
Does anyone have ideas to remedy this situation?
Thanks
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Diesels have the problem you describe. The question is how much lube oil is consumed this way? A liter per 1,000 miles isn't nice but acceptable.
Basically too much air volume is blowing out of the crankcase and carrying with it lube oil mist. Why is that happening?
If your motor has done say, 250,000 miles, it could need new rings.
Older diesels exhausted their vacuum pumps into the motor so a vacuum leak somewhere in the car supplied such excess air. Does your motor (a) have a vacuum pump and (b) if so does it vent into the motor?
Finally, is the engine's lube oil level BETWEEN the notches on the dip stick. Some shops overfill and the excess is blown UP the air oil separator's drain tube on hard acceleration (my experience).
Hope these thoughts help.
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On Mar 9, 4:26 am, "-->> T.G. Lambach <<--" <"T.G. Lambach at NoHamorSpamcomcast.net"> wrote:

Thankyou for your reply. I'm not too sure how much oil it's using - I've had the car for a year and it certainly hasn't been using anything like a liter of oil per 1000 miles in the past, but recently it overheated (nackered water pump impeller) so I've been doing a bit of work on the cooling system. Actually, I took it to a garage (non MB) and they replaced the waterpump and thermostat but it still overheated. After much mucking about with it myself, I tried turning the themostat around and it now runs at normal temperature... In the meantime I'd nackered the radiator with radflush so it got renewed along with ATF cooling pipes, ATF etc...
As part of this, I cleaned the air pipes while they were off and after a few short runs (to test ATF level) they are dripping with oil again inside. I hope the car isn't using more oil than before but will have to wait to be sure.
Haynes suggests that it does have a vacuum pump - I'll have to do some more investigating. I maintain it myself so the oil is at the right level
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The oil in question is a residue, not cosmetically nice but acceptable. The overheating you cite, if sever, could have killed the piston rings' temper and so created an oil burning engine with a lot of compression loss that causes "blow by" into the crankcase. Hopefully that's not the case.
Suggest you keep a log to determine exactly how much oil must be added after X,XXX miles for THAT's the important test.
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Thanks for the advice. A car that uses up a bit of oil I can live with. At least it doesn't seem to be putting out any black smoke so I think the best thing to do is keep an eye on the oil consumption over the next few months. And hope it passes the emissions test in its next MOT in the summer...
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