is your motor a cbfa engine code? if so, im pretty sure its the sai pump. does it in my car too upon initial start up after it sits for a couple hours or over night. its like a loud blowing noise with a high pitched note at times. only lasts about 10 to 20 seconds.
Then it is your water pump going out again. I have the same problem. I'm on my third wp. It was replaced 3 weeks ago and now the sound is back. I have stated that we all should do something about this. An online petition for instance, but i would really need someone with technical background to write it. English is not my native lang and if this is to be done, then it has to be done right and for the sake of all VW TSI owners around the world.
The pumps have been superseded by anew part number with a new bearing: 06H 121 026 AF
Nope. That's old news. 06H 121 026 AF is now superseded by 06H 121 026 BA but the problem is still on. In fact, i have the latest part rev. and it is making the high pitch sound again. 06H 121 026 BA did not solve the problem. VW/AUDI is supposedly working on a new revision now. No ETA so far though.....