Dry Bearing Noise From Engine Bay

[Seatdriver]

Hi again,

 

I am still attempting to track down this dry beating noise that has developed on my Alhambra 130 tdi.

 

I have now been able to re create this noise repeatedly by the following.

 

During an up hill climb (doesn't matter what gear other than not in first) if I depress the accelerator to the floor and as the car begins to accelerate quickly take my foot off the accelerator and at the same time depress the clutch, I get a much louder dry bearing sound.

 

Now I do not believe it is the release bearing on the clutch as the noise can be heared (a lot quieter) when the car is static with the clutch in or out and revving the engine.

 

Just wondering if there are any recirculatory valves on the turbo that could be blocked as at the time I release the accelerator in the scenario above the turbo will be spooling up. Is it possible to stall the turbo? or create a situation where the inlet rotor ends up driving the turbo blades and a reverse effect is created.

 

Anyone out there with good turbo knowledge.