Whistling sound when I let off the throttle ?

[m.c gti]

Can anybody help?
My 57 gti mk5 is making a whistling sound when I let off the throttle here's the things I notice

•the engine has to be up to temp
•it is only there when I take my foot off the throttle
•and it gets high pitched when I turn engine off before releasing an air sound then it goes away

The car is stock no mods as far as I'm aware any light on this problem would be much appreciated thanks

[RENNTAG]

Dont know about the last point but it sounds like the noise you are hearing is just the boost pressure being releaed by the Diverter Valve. This is normal and all part of having a turbo charged car 

[m.c gti]

This is not a sound I have heard on any of my turbo cars it is still there when the turbo is idle when I'm just sat with my engine running.

[edd666999]

do you have or can you make a video of the noise? maybe from outside the car?

[RENNTAG]

So its not just when you lift off the trottle its any time that the engine is not under load?

[m.c gti]

No just when I'm off the throttle and gets louder when engine is switched off a friend said it could be diverted valve but engine light ain't on how can I get a video on here ?

[Moz]

Upload it to youtube and link it.

Was it anything like this noise?

[m.c gti]

Right guys found the little sh*t. When you lift the engine cover off there is like a valve for the air flow like a little rubber diaphragm on the rocker cover anyone know this part name or number

[edd666999]

Right guys found the little sh*t. When you lift the engine cover off there is like a valve for the air flow like a little rubber diaphragm on the rocker cover anyone know this part name or number

  theres alot under there. Pcv valve?

Picture please!

[Snoopy]

Have you seen this thread it may help you.
http://www.mk5golfgti.co.uk/forum/index.php/topic,44709.0.html