Turbo leaking oil - Mercedes ML320 CDi

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Fri 16 Mar 2007 09:45
Turbo leaking oil - Mercedes ML320 CDi - Marcos{P}
Hi all

My 6month old ML320 CDI has had a persistant oil leak for the past 3 months. I noticed it again yesterday and found that the intercooler pipes are full of oil and the oil is finding it's way out of the cool side of the intercooler. Now my technical knowledge of these things is not great but it appears to me that air is drawn through the turbo, goes through the heat exchanger ( intercooler ) and then goes to the cylinders.
My question is this. If so much oil is going through these pipes will it be damaging my engine in any way, I have noticed more smoke than normal when I accelarate so I presume that oil is bieng deposited into the combustion chamber, and where does all this oil come from?
I have also noticed a vibration under heavy accelaration, could this be down to the turbo blades being coated in oil?
The car has been to the dealers 8 times already and is due to go back in today, I have had enough now even though the car is fantastic.
Any help would be appreciated.
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Fri 16 Mar 2007 10:06
Turbo leaking oil - DP
My question is this. If so much oil is going through
these pipes will it be damaging my engine in any way,


The main danger of significant oil intake on a diesel engine is that a diesel engine will actually run on engine oil. If the leak gets to a certain point, the engine will sit there consuming its own engine oil with no easy way of switching it off.

Some oil on the intake side of the engine is normal, as it comes through the crankcase breather system which recirculates gases that have bypassed the piston rings (blow-by gases) into the inlet system to be burned again. I have yet to work on an engine which is 100% effective at separating the gases from the oil that they are contained in.

My Mondeo has very light film of oil on the insides of the intercooler pipework, as did our old 306 and the Golf before that. You need to get the car checked to see if what you have is excessive.

Cheers
DP
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Fri 16 Mar 2007 10:41
Turbo leaking oil - Marcos{P}
This is definately not a thin film of oil, when the intercooler pipe is removed you can pour oil out of it.
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Fri 16 Mar 2007 11:18
Turbo leaking oil - Aprilia
If you can pour oil out of the intercooler then you have a major problem that needs sorting ASAP. Sounds like the oil seals have gone. If this is a nearly new car then really you should insist on a new turbo unit. Intercooler should be thoroughly washed out.
As mentioned, in really bad cases the engine will run on the leakage oil and won't shut off...
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Fri 16 Mar 2007 11:19
Turbo leaking oil - Hamsafar
It certainly doesn't sound right!
It sounds as though excessive oil is accumulating and then under high rpm/load is being blown into the intake manifold and burned.
I'm surprised the dealer hasn't tried harder to cure it by replacing the turbocharger after first checking the vent pipe's output with a catch pot or something.
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Fri 16 Mar 2007 20:18
Turbo leaking oil - Martin1981
I certainly wouldn't expect this on an almost brand new car, especially a Merc. How often are you having to top up the oil as a result of the leak? Sounds like the turbo is to blame and I would strongly suggest that the dealer replaces it to see if that cures the problem. I thought this only happened on older turbo diesels which have covered in excess of 100k. I had this with my 306TD and found I was topping up by around 5 litres between 6k oil changes, but as the car ran fine and the problem never worsened, I just put up with it. The icing on the cake came when the head gasket failed at 150k and ended up swapping the engine with a lower mileage one, since when I have never had to top up between changes and that engine is now on the 150k mark and sweet as a nut.

Martin
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