Hi All,
i'm a newbie but have followed the forum for many years. I have an issue with my E 270cdi 2002. 2 weeks ago i started getting a grinding noise coming from turbo area that could only be heard on deceleration. With the car in park, if i rev it i hear the ''vroom'' of the engine follwed by the turbo whistle then a grinding noise that fades away. It sounds just like a bearing which has lost its lubrication. So removed air filter box and found the noise definitely coming from the turbo. Through some internet research i found out that the turbo is lubricated via a pipe that comes from the upper engine block. So it seems obvious that my problem is with the lubrication system. Having driven the car for 2 weeks until i realised there was a problem, i want to get a new (reconditioned) turbo as mine is probably knackered and i dont want to risk it failing and being catastrophic. My friend has a turbo from a C220cdi and says it is good for models C and E class W203, W209, W210, W211. It's part number is A611 0960999. The part number on my e270 turbo is A647 0960999. Are they compatible? I'm no mechanic but i would have thought that a turbo from a C220cdi would be calibrated for that cars fuel/air/cylinder size and not for a 2.7cdi. Could anyone shed any light on why the turbo has stopped being lubricated. I'm going to delve in again today and take the lubrication feed pipe off and have a look see what's going on. Will i need a new turbo? can i just fix the lubrication issue out and keep original turbo?. I forgot to mention that 5 weeks before this problem started i had the head skimmed and new head gasket etc so the whole top end has been off and rebuilt. I'm wondering if this has something to do with the lubrication pipe not supplying oil.

 

Probably there is nothing wrong with the lubrication. Turbos are very precise components, normally they rotate from 80 000 to 200 000 rpm's (and even up to 250 000 rpm on low inertia turbos), so they work on very tight tolerances. So if there is lubrication issue, and we take consideration the heat at the exhaust side, your turbo would've been toast long time ago.
More likely the sound you hear, is the compressor wheel having contact with the housing. Remove the intake tube from the turbo, and see if there is any play at the turbine shaft. Little axial play is allowed, but no radial play.

If you want to check the oil feed to the turbo, start by removing the fuel pump relay, and start the engine. It will run only for a second, but this is to make sure the fuel rail has no fuel for the next step. Then remove the oil feed from the turbo, place rag under it and get someone to crank the engine. There should be steady flow of oil from the feed line.

 

Thank you my friend, that has shed a bit more light on the matter as that is exactly the type of sound it is, like the compressor wheel having contact with the housing.. I looked at the turbine shaft (gave it a good wiggle) and play seemed to be ok and the turbo generally looked ok but the noise was coming from turbo area. I shall now focus my attention to the compressor wheel, thanks again. (Edit - i tried looking online for the compressor diagram thinking it was a separate component that bolted on to the turbo but realise its part of the whole turbo compressor unit. (I fix moped engines but i'm lost when it comes to cars like mercs). Here in Spain it will cost me around 200 to 250 euros to recon my turbo compressor unit (and thats if i can find somewhere that does it, none of the local mechanics know (thats how backwards it can be). Should i just replace the turbo compressor and will that fix my problem.