Just a quick question, I've ran in to a couple weird issues with my B7, and I've fixed all of them except two (already replaced PCV and DV and applicable hoses). When I turn the car off, I hear the turbo despool, however it's not a smooth sound like most other turbo cars I have heard, it almost sounds rough as it slows. Sort of like a baseball card stuck in a bicycle wheel, you can hear it slow all the way down, but the sound is a plastic noise, not a metal grinding or a screech from metal-on-metal contact. Any thoughts on what this could be?

 

i dont kno wut it is but mines doin the same thing.. i didnt notice it till today.. idk if it because i drop a k&n filter in the stock box or wut.. weird

 

Probably the radiator fan or secondary air pump.

If the engine is off it is impossible for the turbo to make any noise

 

True, I guess if the turbo isn't making noise while on boost, it wouldn't as the impeller slows after the car is turned off... Is the radiator fan or secondary air pump a known failure point on a B7?

 

It'd be the first I've heard of it if it was. Sounds to me like maybe something is caught in the radiator fan shroud and you don't hear it driving because of the engine noise but once the motor is off and the fan is winding down then you hear the fan blades hitting it. Have you looked at the fan for anything that might be stuck there?

 

If it was the turbo making noise when the engine was shutting down you would hear it everytime raise the throttle. Its electronically limited to 4k at idle so i would redline it and let it drop to idle and do it and see if you can hear what your hearing. If not its something else. I'm more inclined to agree with A4cragman with something to do with the radiator fan. Secondary air pump is possible but you would hear it more when you first started the car cold

 

^exactly. I know all about the SAP, my b5 to this day gives me the finger with that pump and what you describe doesn't resemble that particular nuisance hardly at all. Doesn't mean it can be ruled out by all means, but I wouldn't put much on that being the problem.