I have Cooper S 2009.

I've noticed that when I press pedal gas and then release it I hear some kind of whistle noise. I'm not sure where it goes from. What could this be?

 

You hear a whistle only after releasing the gas pedal and not while you're accelerating? Hear anything at idle?

 

Maybe there is something faint that I don't hear, but in general I don't hear nothing at idle. I hear a clear whistle after I release the gas pedal. I must say that if I press the gas pedal just a little bit I don't hear a whistle. But, if I press, let's say, a half way down and release, I do hear a clear whistle.

 

Kinda new to the turbo game, but have driven an 84 T-Bird turbo (a lot) and an 89 Probe GT turbo (a lot) in the past, both were dad's cars, and I used and abused BOTH when he was out of town. LOL. The whistle you hear on acceleration is turbo boost, the pssshhh sound you hear on decel is the wastegate/recirc valve dumping pressure when throttle is released. Kinda basic knowledge, I know. But that's what I have to offer. Sounds like it's working just fine to me. Maybe I am missing something?

 

I thought that it might be the turbo, but I don't remember hearing whistle in past 2 years that I have the car.

 

You might here it a little more since its getting closer to winter.