Do Turbo Units Leak Oil ????

[romas7887]

hello people,

question....my w211 e270 cdi '03 went for an inspection at mercedes edmonton. They said it had an oil leak in the turbo unit and would cost £3000 to repair. I took it to Mercaid yesterday and the tech said it is normally for turbo units to leak oil around the seal. He said even if you install a new unit it would shortly leak oil as well.

I look at the car on the ramp and when the tray was taken off there was a small amount of oil deposits on tray. The pipe had oil deposits on it but he said that there is no need to replace the unit yet. Is this correct and when should i replace the unit ????

 

[fredfloggle]

On a turbo with fixed vane geometry , the only oil leaks that can occur are inside the housing (apart for oil feed and drain to sump ) which will manifest itself in smoke , and or slop in the pipework to the intercooler and the intercooler itself .
Never having messed with a variable vane turbo , I can't confirm if there is any oil feed to linkages etc , but I would be surprised if this is the case .

Unless like big and I mean BIG industrial engines , MB provide a slop drain (a gravity flap that opens when oil build up) , I also can't see where your leak could come from .

 

[Dieselman]

It'll be breather oil being blown out past the seals on the inlet duct after the turbo.

 

[spitzkop]

To add to dieselman, the turbo has a high pressure oil feed coming into the top of the turbo (looking down from under the bonnet), there is a seal on the engine (I think copper, but cant rightly remember) and a copper seal on the turbo. On the underside, there is a low pressure return pipe, again copper seals at the turbo and a push fit into the crankcase. Any wear or ageing on these seals can lead to oil leaks. As mentioned, check your exhaust pipe and look for white smoke (oil leaking into the combustion chambers/exhaust manifold from within the turbo itself).

Firstly, verify if there is oil being burnt, if there isnt, check around the turbo by cleaning and dusting with chalk, and also on the cylinder head where the high pressure oil feeds out from and the crankcase where the low pressure return is.

The breather pipe as mentioned by dieselman tends to leak at the top of the cylinder head (a black circular seperator) and can also leak on the t-junction into the turbo air inlet pipe. You should hear a wheezing if there is a leak on this junction though.