gnomemade

I've reached my frustration limit trying to figure out what's making this noise, need a little help here

It's my wife's car, a 02 GT vert. It's pretty much stock except for a BBK cold-air intake and Magnaflow muffs. About a week ago it started making this really odd whining or whistling sound, kinda like a banshee.

I uploaded an mp3 of the sound it's making to
http://www.fileden.com/files/2007/6/...tang_whine.mp3

Here's what I've done/checked so far:

- ps fluid is at the proper levels and I didn't notice any change with the steering when the sound started.
- I removed the drive belt and started her up, the sound goes away.
- Belt looks good, it's got about 15k miles on it. The noise does not change or go away if I spray belt dressing on it
- Replaced the smooth surface idler pully, it had a bit of wiggle and a little noise in the bearing, but not horrible.
- Replaced the belt tensioner assembly. Prolly a waste of $30 but it looked like it was oscillating when the engine was running a little more then it should be.
- The volume of the sound changes a little when the a/c is on, but not very significantly. The compressor clutch was replaced about 2 years/25k ago.
- The alternator was replaced about 1.5 years/15k ago.


Any ideas? This thing is driving me crazy and i spent the whole damn day dorking with it.

WhiteFoxGT

If the noise isnt really changin with the compressor kicking on, then it sounds like the Alt taking a dump on you. Remove the belt, and reach down and see if you can wiggle the compressor clutch (the piece on the very end, not where the belt rides.) It should have no play in it. A bad bearing in an alternator can make some weird *** noises. The diodes switching will put different loads on the armature and can make a noisey bearing sound like that. So check the AC and get back to me

Obsequious1

It never happened to my car but some of the guys in here say they get a simular sound from the CAI they put on.

my little red 90

look in the back seat. it may be my ex- mother-in-law.

gnomemade

Thanks WhiteFoxGT. So, I took the belt off and I can turn the compressor clutch freely (with the engine not running). From what you said, it sounds like that should not happen? I don't get it, because the a/c is blowing cold air and seems to be working ok. On the other hand, the noise does seem to be coming from the general area of the compressor, or it least it sounds like that using my ghetto homemade stethoscope Does the whole compressor need to come off to replace the clutch?

gnomemade

The cold air kit has been on it for several years now. a while back one of the connecting gaskets on it came loose and it was noisy, but it was more of a hissing noise then a whistle.

WhiteFoxGT

I honestly cant remember, but i think you shoud be able to turn it while its disengaged, but you shouldnt have any in and out movement, like it shouldnt wobble. The clutch can be replaced on the vehicle, but its a lot easier to do it on a bench. If that is your problem

gnomemade

oh, ok, I got ya. I was thinking wiggle as left to right spinning movement, not front/back. There's no wiggle front/back. After thinking about it a bit, it makes sense that it freely rotates while the engine is not running and/or the a/c is not engaged.

gnomemade

dammit. it was the bearings in the ribbed idler pulley that's above the a/c compressor. the same one i wrapped the belt around like 5 times but otherwise ignored live and learn....

Obsequious1

THAT WAS A STRANGE SOUND FOR PULLEY BEARINGS. I HAD PULLEY GO ON MY CAR TOO BUT IT WAS MORE OF A GRINDING SOUND.