So over this past Christmas break I replaced the old original turbos from my '00 B5 with stock replacements. They used to make the loud "dentist drill" whine I'm sure some of you are familiar with. I think I put it all back together correctly and it runs great but I still can hear that whine a little bit. Though it is very, very faint it is the same sound that it was before which were from blown turbos. I hear it at very light throttle.

Here is a sound clip of what it sounded like BEFORE the replacement which is a much louder version of how it still sounds today:
Audi S4 turbo boost leak? - YouTube

Do your S4's make any faint sound like this at all? What do you think this could be? Is a turbo still bad? Thanks

 

The turbo spooling noise is normal on turbocharged vehicles. Just as long as it is not excessive & there are no oil leaks/consumption issues or check engine light on.

 

How many miles is on your S4?

 

Dude my car has over 200k on the stock turbos (B5S4) and sounds nothing like that.

 

I replaced them at 107k miles. Do you think it might have an oil starvation or something?

 

did you re-use any metal gaskets when you put everything back together?

 

No, i think you may have a small boost leak. They are pretty common on the B5 S4. Or it could be normal. Whatever it is im sure its very minor.

 

Well my B5 S4 has a very very faint whistle not the dentist drill or anything just a faint whistle. Do you have any idea what that could be?

Thanks!

 

it could be a boost leak. check all vac lines, boost hoses and your spider-hose.

 

WTF WTF WTF Today I had it apart doing the timing belt and to fulfill my curiosity I pulled the lower hose off the driver side intercooler and sure enough oil dumps out!! This same thing happened when I replaced the old turbos.
What the hell is going on here is it possible I got a bad turbo? They're brand new BW K03's how could one be bad?!?