Thread: [update]whistle when in boost

I have checked for boost leaks and i had a few but fixed them all..... will the boost gauge be holding say 15psi for a long time or will the boost gauge drop psi like every 4seconds? thats what mine does... welll anyway every time i hit boost my car starts to whistle and the boost gauge wont really holds boost the gauge moves around really fast.... im thinking its my waste gate because the sound is coming from somewhere around my manifold and turbo. did anyone have this problem? can the turbo just be getting bad?

I had a similar case in my old T25 when it was going out, stated whistleling andburning oil

hmmm im not burning any oil

Bearings in turbo? Although if you're not burning oil in it it seems unlikely. Double check for boost leaks man. How many miles on the turbo?

Maybe your wastegate is stuck open? That seems like it would cause those issues.

i was thinking the wasegate too just because i checked for all the leaks and found nothing. the turbo has about 2k miles on it since i got the motor from greg.

Could very well be the wastegate flap not opening fully and that's where you're getting the whistle from? Pinch the wastegate vacuum source off and verify if the car goes into boost and falls back out again, or not. If it doesn't bleed off (should keep climbing as long as the turbo is spooling), you know it's the wastegate. Just be mindful of your boost gauge to ensure you don't achieve overboost.

I already told you, you must have a pin sized hole in one of your couplers, vacum lines, etc. Once it sees boost it will whistle/whine. Ive had one like that on my truck, replaced the coupler and it quit.

Damn kids with ADD.

i'd check for bent fins on the turbo wheels as well. i put a turbo on a 1.8T Passat for the same issue and it had a bent fin on the compressor wheel. just a thought...

i had the same problem with my t25 setup, it was my cheap ass ebay bov...lol. it got stuck open just a little

like i said i CHECKED FOR BOOST LEAKS!