turbo hiss replaced with a whine

[theBird]

I can normally find an answer to any question I have by searching but after two hours, here I am.

My daily driver stock red top with a t28 and just tonight the turbo has started making a supercharger-type sound only when its boosting. The sound is consistent 1 psi up to 9 psi. In other words, the normal hiss has been replaced with a slightly louder whine. Everything seems normal except for that noise. Oil pressure is fine. It still makes good power with no smoke, no strange smell, no liquid leaks and as far as I can tell no exhaust leaks. I replaced the turbo to manifold and manifold to block gaskets and bolts about 6 months ago and it doesn't sound like its the same problem as before with the bolts coming loose.

Are these symptoms of a bad turbo or could it just be a boost leak?

I'll post a clip if necessary.

[adrianfromthecastle]

when I very first got my sr, about a week later, i had somewhat a similar whine as well (considerably louder that the regular spool). checked it out and found a loose water line (the one that went to the turbo, coolant starting pouring out like on the 2nd day), replaced it, and the sound went away... i'm not sure if mine was spontaneous or not, but have you checked all the lines? coolant level?

[Justin35ll]

Mine whined during boost after I lost oil pressure and the turbo siezed, then it broke free and had about 2mm of shaft play.. so i had a blown turbo.you could pull off the intake pipe and check the shaft play of the turbo

[theBird]

I found the problem! it was a boost leak off the compressor outlet. The turbo adapter allen screws were loose. Thanks for the replies and I know its hard to diagnose something you can't hear or see for yourself.