Zo6Sel

I think you may be right, it seems to be getting worse and I know it does get louder as I use the a/c on very hot days. A lot of times I so t use the a/c at all because I like the sound of the idle better without it lol. Does seem to be coming from the alternator though, it is doing it at idle but it's very quiet. You can hear it pretty loud on this video if it idling though. In person the background noise of the engine almost overpowers it... I'll attach the video in a few when it's done uploading Also I found that the bottom of the intake boot on the throttle body had slipped off. AND the vararam intake is dented on the edge and won't straighten out and there is a small gap between that and the boot around it...

Zo6Sel

cudamax

Sorry Had to go out for some more pop and do a few burnouts in my old c4
Dude it's on the drs side foresure Pull the belt and spin each by hand I say Alt or p/s pump but my moneys on that alt bet-cha it's the brushes and just spinning by hand it will squeak You got time to do it I/m watch t.v eating a pizza

Zo6Sel

Haha well I'm thinking it may be the alt. I spin it and I can hear some friction in there but it's hard to tell if it would be a whistle at higher rotation. I'm thinking it will be though... Thanks a lot for your time and info guys!

Zo6Sel

Well a new alternator fixed the whine but now I'm getting a charge system fault code when I start the car... I watch the voltage go up when the rpms do so I'm not sure what the problem there is...

cudamax

Is the Idiot light coming on? I think it has to see at least 12 volts or so otherwise it's triggered on

Zo6Sel

Nope just a little message saying charge system fault. Once I hit reset it stays off.

cudamax

Damn if it does it again or on start up Bring it back and get another one the other one wasn't doing that ****, Right

Zo6Sel

Nope last one didn't do it... I'll be having them order another one for me to exchange. That DAMN noise is not gone though!! It doesn't whistle at idle anymore but it does have a very faint whistle still while slowing down and it stops right before I come to a stop. It's the same as in the videos I posted just not quite as loud anymore

dadaroo

I hope you kept the old one, if not you may be very sorry. I can explain later or you just search on C5 alternators.

Zo6Sel

I read a little on the alternator and it seems that this one will be fine but it'll throw that code correct? I can deal with that for awhile I guess, it only says that after it's sat for a few hours. After the first start of the day it doesn't say it. I'm thinking the alt issue came after I had made this initial post because I wasn't able to hear a whistle when stopped and now that I replaced the alt there no noise again. But once it warms up and after a little bit of driving (I'm guessing when the engine bay warms up) that damn squeal or whistle from the videos comes back!

cudamax

Put the old one back on and return the newer/rebuilt one and just turn the radio up louder while cruz-in

Zo6Sel

Haha nah, other than the squeal the car sounds too good for a radio

masoud

I had a squeal (have no access to YouTube in Iran, so I cannot see/hear the type), Had to replace the following stuff:
(Mechanic #1):
Main Idler, no change. It was a bit loose.
Alternator: Hard to procure. Didn't fix it. Paid shipping (twice) and restocking fee.
(Stealership):
Harmonic damper: I thought it'd fix it, but no. It came back after 30 minutes and car fully warming up.

The noise seemed to be from the clutch area.
I finally did a clutch burn out (While car in motion, clutch-in, up-shift, rev the engine high and eeease the clutch out), and the noise went away.
YMMV, and it may come back at any time.
FWIW, I have a 04 z06.

Zo6Sel

Did it do it all the time or only on occasion? Mine does it when slowing down then stops at about 5mph, in gear or out of gear on brakes or off brakes, neither seem to make a difference... It's also only after driving for roughly a half hr so I'm thinking maybe something is heating up in the bay and expanding possibly?