220Cdi whistleing noise as revs die when cold

[egrid1]

Hi

I have a strange whistling noise coming from around the turbo/ air box area on my 220cdi (611 engine). It sounds like a police car siren in the distance.

The noise is usually only noticeable when the car is cold and at lower revs. When at constant revs it cannot be heard but comes in as the revs die to idle, both when the car is stationary and moving.
The noise seems to disappear as it warms up.

I have had a look at the hoses and cannot see any obvious holes - could it be a problem with the turbo itself, or is it more likely to be a hole in the pipework that I have yet to find?

Any thoughts appreciated.
Thanks

 

[myblueml]

It's probably the turbo spooling down and up as you press the accelerator, just after I got my ML 270 I heard the noise and started looking for the cops or ambulance, it took some time for it to twig that the noise corresponded to the accelerator position on light throttle.

Cheers.

 

[egrid1]

Thanks for your reply - my concern is that it is a relatively new noise at 120K miles, so I am not sure about the noise coming from it spooling, so at this stage Ifeel I ought to investigate a little further to rule out possible other causes before relaxing and putting it down to spooling noise.

I have looked on some other threads and some people seem to suggest a leak in the pipes to the intercooler. There seems to be a whole host of different pipes around the turbo - does anyone know if there is a common weak point where I should start looking?

Can I remove all of the pipework from the turbo / intercooler freely to inspect - is it just jubilee type clamps - or are their seals or anything that I might disturb?

Does the intercooler just rely on air to cool, or will some of the pipes have water in them ?

Thanks

 

[Dieselman]

It's an air to air intercooler, so no water to bother about. If the car has full power under boost then it's not likely to be a split pipe, but would be worth checking the intercooler for leaks. Any leaks should be evident by slight oil leakage.

The noise does sound turbo related so investigate there. Try a strong dose of injector cleaner which might free off any sticky turbo vanes.

 

[ringway]

My Sprinter makes this noise 2148cc CDI.

I have always assumed that this was normal, although the van has lost a lot of its power on two occasions in the last 12 months. (I am reasonably satisfied with how the van operates most of the time).

I did a brief check on the hoses and looked for any splits or holes but found nothing. The van then resumed normal operation.

The viscous fan is running full time at the moment and I have received advice to take back the van to the garage that recently installed a new thermostat.

Could there be a connection between the whistling/power loss/viscous fan issues?

 

[Hartzpartz]

I noticed a "hissing" noise under load from my E220CDi and found the cause to be a detached boost pipe at the intercooler "in" connection (hose from turbo compressor "out"). The end of the rubber hose has a metal collar which pushes into the intercooler and is retained by a snap ring. Easily accesed from below if you open the N/S fog lamp bulb acces panel.

This is the second time this hose has come loose so I wonder if I may have an overboost issue or if these boost hoses often come loose?

Hope this helps to sort your problem.