Turbo whistle when cold?

[dci]

Over the last few days I've had a whistle coming from the turbo on a mk3 clio dci 85.

It only seems to be when cold and only when you lift your foot from the accelerator and changing gear, sounds kind of like a dump valve style noise. In the 5 months I've owned the car it's never made this noise.

Any idea's if the noise is a bad sign or normal?

Richard

[annodomini2]

dci said:

Over the last few days I've had a whistle coming from the turbo on a mk3 clio dci 85.

It only seems to be when cold and only when you lift your foot from the accelerator and changing gear, sounds kind of like a dump valve style noise. In the 5 months I've owned the car it's never made this noise.

Any idea's if the noise is a bad sign or normal?

Richard

They have a dump valve, could be the cold air resulting in more pressure on overrun, activating the dump valve.

[Portuguy]

Hi i get a strange sound like a clarinette badly blown, from the turbo on my 1.8 Sharan especially when cold and accelerating. I was wondering the same . A bad sign? And what is a " dump valve"? An emergency pressure valve?

[annodomini2]

Portuguy said:

Hi i get a strange sound like a clarinette badly blown, from the turbo on my 1.8 Sharan especially when cold and accelerating. I was wondering the same . A bad sign? And what is a " dump valve"? An emergency pressure valve?

The dump valve relieves pressure in the inlet, they are more for petrol cars with a throttle, where when the throttle is closed after being in a high torque/high boost situation, the pressure builds in the inlet as the turbo is still spinning, this just relieves the pressure.

http://en.wikipedia.org/wiki/Blowoff_valve