Sprinter turbo noise

[Kam]

My sprinter 311cdi has been having problems with the turbo and exhanust. Problems is when driving and the revs are over 2000 i can hear the turbo circulating the air inside the cabin, and the van does not have the full power, but yet i can hear the turbo whistling.
Got it checked by my mechanic and he says the turbo has no leaks and has not disconnected anywhere. Then he pointed out that the exhaust is not giving out enough emissions when they tried to get a emissions test. So his conclussion is that the exhaust has a blockage somwhere but cannot be 100% sure.
So all i can do is get a new exhaust system which is one full piece and is costing near the £200 mark. Not too fussed about the price for the exhaust just the fact that it could not be that.
Has anyone else ever had this issue with a sprinter?
Or can any one give some advice on what to test or why this could be happening.

 

[Dieselman]

Sounds like the Cat is blocked causing the turbo to stall.

If the exhaust is removed and the cat emptied out that will probably fix it and release some extra ponies.

There are two cats in two different sections of the exhaust. I suspect the pre cat which is in a short section at the front.

 

[Flash]

The turbo should only sound it’s traditional whistling noise upon releasing the foot off the accelerator upon acceleration and not as how you described. If the vehicle is not losing power then I would not suspect it being the turbo BUT I would not think that the exhaust would be related the turbo noise issue. At least the Sprinter exhaust is a full one piece item. Bit of a strange one this one.

 

[GRAV888]

Maybe an intercooler pipe split.
Just done one on my mates sprinter.

 

[Kam]

the turbo whistling noise can only be heard upon realease of the pedal. It will be going in next day or two to get exhaust changed and hopefully that will sort the issue out.
will keep post updated as it progresses