When I turn my 2001 225 TT on theres this loud whistle (you can hear it for a few seconds) and the car goes back to normal. Car seems to run fine. I just dont know if theres a deeper problem. Any ideas or pointers anybody?

 

How many miles on do you have on it? It could be a number of things from your timing belt. If you have more than about 60,000 you may want to check into getting your timing belt replaced if you havent done that yet.

 

Car has done 56k ,dont know alot about Turbos but could it be oil starvation ?

 

More than likely what you are describing is injector noise.

 

i would just make sure your timing belt, water pump, tensior, idler pulley, etc are all in good working conditon. its really hard to tell so i would just replace all that stuff especially if your over 60k. your turbo is fine as long as your not see any leaks after you drive. (well... your need a boost gauge to tell if your having a problem with the turbo system.) take off the underbody panels and look for any oil leaks coming from the turbo area.( by the intake and exhaust side) also look by the downpipe.

 

Just went back and re-read your post... The noise goes away after 1 or 2 minutes? It may be simply the secondary air pump.

 

turbo noise like the turbo is spooling is my guess as to what you're trying to describe. Does it only happen on cold startups?

I read somewhere that the turbo spins a bit on cold startup to get it warmed up or something. Can't confirm it, but I believe that was the explanation. I hear it too with my car.

 

Nope, secondary air pump. Turbo spins all the time from the exhaust and only boosts when the wastegate closes.

 

ehh, i dont know.

theres a very clear difference in noise between normal light throttle acceleration, and cold light throttle acceleration. Doesn't sound like secondary air to me. The sound of the turbo spooling when its cold is fairly prominent with my car.

 

yeah i agree he doesnt seem to be describing the sec air pump but also says he hears a whistle tho.....be a little more specific with the noise and we might be able to help.