I tried searching the forum for this answer, but don't think the other answers involved my situation specifically.

I have a 2000 convertible that when started from cold (sitting overnight) emits a load squealing noise from under the hood. The best I can tell, it is an accessory belt, but I can't tell where exactly it is coming from. It isn't the air con belt though, for sure. The belt appears to be pretty new. The car is new to me, without much of a documented history.

Once the car has been running/driving for 10 or 15 minutes, the noise stops, and doesn't reoccur unless the car has been sitting for many hours, or even overnight.

The noise is loud enough to be heard inside the car with the radio on, so this is clearly not just some minor noise.

Any ideas on how to start diagnosing what causes this, and how to repair?

-David

 

Mine does the same.

I think I've read that the Napa Gatorbacks are the way to go on belts.

 

Are you sure you are really seeing the A/C belt?

There are 2 belts on your Corvette. The easy one to see is the serpentine belt that drives the accessories - except the A/C. That one is a much smaller belt and much harder to see. It is behind the serpentine belt, down low.

You'll need to remove the serpentine belt to get to it. Use the Gates Gatorback product - especially for the A/C since that belt gets hot.

Change them both.

 

I had that issue and it was the idler/tensioner pulleys

 

If you can get things squealing you can use a length of hose as a noise sensor.. One end in your ear and the other looking around for the loudest sound.. It's most likely one or both of the belts... Be careful around those moving belts!!!

I put Gator Backs on my car but they don't fit as well as I would have liked... The "genuine GM part" would fit better but they do cost more... Here is good source of low cost GM parts...

http://www.gmpartshouse.com/

 

I am with this guy... replace both Idler pulleys, problem solved!

 

I had this problem 3 separate times on my 2000. Replacing the belts never did anything for the noise, it always returned within weeks.

Once it was a wobbly crank pulley, another time the A/C tensioner pulley, another was a leaking water pump.

You can easily look for a wobbly crank pulley, if the crank pulley wobbles you're in for an expensive fix and can be a common problem on any LS engine.

It's fairly easy to pop off the belts, at least you can isolate the problem to one belt or the other.

 

I had this problem. Replaced both belts. Squeal no more. I'd try that first, its easy and cheap.

 

I had the same problem!
I narrowed it down to something on the a/c belts system
I took off both idlers and found a slight bit of rust on the back of the dust shield where it meets the bearing

I simply sanded where it contacted and put a little grease between the two points.

solved my problem!!

 

I have the same problem currently. Only squeals for the first 10 minutes of driving each day, and generally only over 1500ish rpm. Park it for the night and it is there again the next morning.

General troubleshooting steps are to remove one/both belts to narrow down the offending belt/accessories. Then try spraying a bit of water on the belt and see if it goes away/changes to narrow down if it is belt related or bearings somewhere.

Mine I'm not having much luck with... I've replaced both belts, followed by both of the tensioners. (figured they probably needed changing, had the car for like 6 months) Sound seemed at that point to come from the A/C drive. Thought that had it fixed, but it only lasted about 2-3 weeks and it came back just as before. Went ahead and replaced both idlers, no change.

Just today I degreased/cleaned all of the pulleys and belts, thinking maybe powersteering fluid or coolant or something was dripping onto them, etc. Didn't help, made it worse briefly if anything. Sound stops for a second when I spray water on the main belt (and then gets worse briefly) so it doesn't seem to be a bearing from one of the accessories. Not sure what else to check now, I went with Dayco belts from Advance autoparts, thinking maybe I'll try another brand. I currently have the A/C belt off right now to pinpoint for sure which system is the culprit tomorrow morning. I'm wondering if one of the tensioners I got originally was bad to start with (Dayco brand for both, from Advance).

This is an annoying pain in the *** problem to have... Had the lousy belts off a dozen times in the last month screwing around with this crap. Good luck with yours.

 

Take the dust shield off the 2 ilders on the a/c system and check for rust.
my theory is that there is some contact between the dust shield and the idler pulley

my noise went away!!

 

I had the cold squealing problem about a year ago,installed 2 Gatorback belts and haven't heard a chirp since.

 

I just solved my squeaking on startup problem. The small hose that runs from the top of the radiator on the right-hand side to a small pipe just above the pulley on the water pump was leaking some after letting the car sit overnight. It would drip right onto the belt. I tightened the clamp and stopped the leak and the chirping.

 

I agree, this solved my chirping problem! I replaced the clamp though, haven't heard a peep since....it's been over two years now.