I hate this #$%! noise!

[KANE]

Found the #$%! noise!

I still have this noise- any one had this?

madmad

I have replaced the tensioners... I have replaced the belts...

I have listened to the accessories with a stethascope. They all sound good.

The power steering pump sounds suspect though. It seems to have some play and makes a ticking noise as I twist it when I turn it. However, the squeak does not not go away or get worse when I turn the wheels. Running the AC doesn't change it. Pulling on the tensioner (to tighten it) doesn't change it either.

I don't think it is the water pump. It spins freely and without excessive play.

I checked the knowledge base and I didn't see anything about the pump.

I can hear a slight drag across the brushes in the alternator when I spin it- but there isn't any change in the voltage with/without accessories on (AC/heater/lights). It isn't loose either (that would go to bearings).

Any ideas?

It was the alternator... read below.

 

[gmjunkie]

Mine has some noise!! I think mine is piston noise mostly Cold,But it's still there at Opp Temp. Just not as bad!! I didn't notice it until they fixed my Transmission.They Flashed my ECM too,and now it Spark Knock's and don't run as Hard ether!! ad

 

[99WhiteC5Coupe]

I still have this noise- any one had this?

madmad

I have replaced the tensioners... I have replaced the belts...

I have listened to the accessories with a stethascope. They all sound good.

The power steering pump sounds suspect though. It seems to have some play and makes a ticking noise as I twist it when I turn it. However, the squeak does not not go away or get worse when I turn the wheels. Running the AC doesn't change it. Pulling on the tensioner (to tighten it) doesn't change it either.

I don't think it is the water pump. It spins freely and without excessive play.

I checked the knowledge base and I didn't see anything about the pump.

I can hear a slight drag across the brushes in the alternator when I spin it- but there isn't any change in the voltage with/without accessories on (AC/heater/lights). It isn't loose either (that would go to bearings).

Any ideas?

You should review this TSB: http://corvetteactioncenter.com/kb/question.php?qstId=258

A squeak from the engine compartmetn on my 1999 C5 coupe was eliminated by replacement of the idler pulley specified in this TSB (the one under the alternator).

The TSB applies to 1997 - 1999 C5's (and other vehicles with the LS1 engine).

Good luck - I'll bet this is where your squeak is coming from.

 

[KANE]

You should review this TSB: http://corvetteactioncenter.com/kb/question.php?qstId=258

A squeak from the engine compartmetn on my 1999 C5 coupe was eliminated by replacement of the idler pulley specified in this TSB (the one under the alternator).

The TSB applies to 1997 - 1999 C5's (and other vehicles with the LS1 engine).

Good luck - I'll bet this is where your squeak is coming from.

Thanks 99- but I already did that. Both the AC and main idlers are new. No change. I did see a TSB for the alternator...

I'm begining to wonder if I should get a belt and test each accessorry with a pulley and my drill (replicate and isolate). If it sequaks- it dies!

 

[Bioscache2]

does it change with engine speed? I had a similiar noise but I changed the belts and it was gone, but you said you already did that

also is it more or less prevelant at operating temp versus start up?

 

[Norman Clemmer]

I had a belt noise that wouldn't go away. Didn't figure it out until after changing belts, idler pulleys etc. It was the clutches on the air compressor. The noise transposed thru the car and did not sound that is where is was comming from, but it was.

 

[KANE]

UPDATE

I had a belt noise that wouldn't go away. Didn't figure it out until after changing belts, idler pulleys etc. It was the clutches on the air compressor. The noise transposed thru the car and did not sound that is where is was comming from, but it was.

I FOUND IT!!!

Close Norman, it was warped dust cover AND the alternator

Subject: Intermittent Accessory Drive Rumble Noise During Garage Shift and/or During Parking Lot Maneuvers (Install New Generator with Decoupler Pulley and Accessory Drive Tensioner)
Source: Chevrolet Dealer Technical Service Bulletin
Number: 99-06-04-029A

Models: 1997-2000 Chevrolet Corvette with 5.7 L Engine (VIN G -- RPO LS1) and 4L60-E Automatic Transmission (RPO M30)

This bulletin is being revised to update the correction procedure. Please discard Corporate Bulletin Number 99-06-04-029 (Section 06 -- Engine).

Condition: Some customers may comment on an intermittent accessory drive rumble noise when performing a garage shift and/or during parking lot maneuvers, such as turning the steering wheel to the lock position. This noise may also occur when turning on the air conditioning at idle conditions.

Cause: Engine idle speed may drop below 600 RPM while performing a garage shift, turning the steering wheel to the lock position, or turning on the air conditioning. This noise may be amplified by a large rate of change in engine RPM. This condition can also be aggravated by different low engine RPM driving conditions.

Correction: A new Generator with Decoupler Pulley and reduced damping Accessory Drive Tensioner was implemented for all Corvettes with automatic transmissions at 2001 SOP (Start Of Production). The generator with decoupler pulley is used only on Corvettes equipped with an automatic transmission. The reduced damping accessory drive tensioner is used on all 2001 Corvettes.

So, I've ordered a new alternator from these guys- http://www.buy-oem-parts.com/storefront.htm

Hint for other folks: the failure of the part sounds kinda like rocks jingling in a coffee can through the rpm band.

http://www.corvetteactioncenter.com/kb/question.php?qstId=260

 

[99WhiteC5Coupe]

I FOUND IT!!!

Close Norman, it was warped dust cover AND the alternator



So, I've ordered a new alternator from these guys- http://www.buy-oem-parts.com/storefront.htm

Hint for other folks: the failure of the part sounds kinda like rocks jingling in a coffee can through the rpm band.

http://www.corvetteactioncenter.com/kb/question.php?qstId=260

I'm glad you determined what the problem was. I also had this TSB done on my car under the new car warranty because it would make a strong "rumble" noise when shifting into reverse with the a/c on.

The original alternator did not make a noise - just the "rumble" when shifting out of park and into gear with the a/c on.

I did not mention this TSB in my prior post because you described in your original post the sound as a "squeak", not the rocks in a can sound.

The quality of the alternators are poor. The replacement alternator failed while I was out-of-state, on vacation. The third replacement also failed later, making a very loud "rocks jingling in a coffee can" sound. It was the decoupler pulley that was defective. The entire alternator was replaced again by a Chevrolet dealer, and I later learned the decoupler pulley can be replaced if the alternator body is not defective.

Good luck - the alternator is an expensive part.