on my 01 it sounded like the turbo was sqwueling like a bearing sounds when it goes bad. so i checked it out and it turned out to be a exhaust leak i lost two bolts and two spacers that hold the exhaust manifold on and a third one was on its way it was way loose so i retorqued all of them and replaced the two missing and now no more sqwueling.
a lot of you probably know this but i guess that is common on 2nd gen 24valves so check them atleast every month ill do it every week those bolts and spacers are not cheap.

 

Does your 01 have the small pieces of steel that hold the heads of the bolts? Thought about retorquing mine but I'm not quite sure if it would do more harm than good to take those straps off and torque it again...

 

Mine did the same thing with 2 of the bolts. Thanks to a awsome DB member he sent me 2 bolts for free.

 

no i didnt have the metal straps but my 04 does so you shouldn't have to worry about yours loosening up

 

make sure you get it hot then retorque them, i check mine every service to make sure my are tight, seen many of them missing thru the years