Pir8Diver

We took our 2007 vert to the local Chevy dealer on Saturday. They changed the drive belt. Initially no squeak/chirp but after a road trip the noise came back. We've only had the car a week. During the purchase we were able to secure a 24 month/24,000 mile power train warranty so IF something major like the crankshaft pulley is failing it **should** be covered.

titanescape

Was it making that "chirping" noise prior to the new belt? I was thinking about changing the belt but when I inspected it there were no cracks or anything. Since the soap trick stopped it, I was going to take the advise of the above poster and change the belt. As of lunch time(about an hour ago) I filled up then fired her up and listened for the noise. Still nothing. It's a rainy raw day here so when I get home I will check for noise again. If it comes back, I'll be using a hose, long screw driver(with a wooden handle) or mechanics stethoscope to pinpoint the noise. I really don't trust the Stealership...

Pir8Diver

The squeak/chirp was there prior to the new drive belt. It's also present when the A/C is turned off. The noise does go away when water is applied on the underside of the belt. Guess we'll have to get a mechanic's stethoscope to see if we can pinpoint the source too.

Jaime-Corvette

I would like to make a disclaimer as i'm not exactly sure if noise does actually come from the balancer or not. I do know that if the harmonic balancer is really wobbly and/or the rubber part from the inside of the pulley is coming apart then that is indication that it is a bad pulley. With the rubber part coming apart from the pulley it would also make the engine vibrate a lot and make that noise even if the balancer isnt wobbly and turning fine.

This is also why I would get an all metal one as a replacement and never worry about it. One like an ATI Super Damper.

Krusty84

Since we are guessing here, I guess bad tensioner. Check to see if the tensioner is moving. If it is moving quite a bit, you probably found your problem.

Jaime-Corvette

This is where I am at...
Well after I replaced my radiator, I had some antifreeze leak onto my belt and what not. I heard that antifreeze isnt exactly good for the belts.
Before that on every cold start it would chirp a little until warmed up enough.

Today I tried the trick where you put soap onto the underside of the belt and it completely stopped chirping immediately. I let the car idle for about 10 minutes and the sound slowly started coming back very very faintly. Im sure if I drove it for some time it would be back how it was all together.

I ordered a Gates belt and I'll get it tomorrow morning. I'll work on putting it on and report back with you guys. If the problem persists, I will be taking the next step as to which pulley or tensioner it might be.

(A lot of people recommend that if you are changing a belt for its age or condition and depending on your car's age, to replace all pulleys and tensioner all in one go to save problems in the future.)

Pir8Diver

I talked to my brother who is a professional mechanic/service writer (built IRL engines in the Aurora days). Based on our vert's symptoms he said it sounds like an idler or tensioner bearing.

Jaime-Corvette

Did you ever find the source? I'm not sure if you have a new belt or not but if you do.. . look for where it's coming from and plan on changing that part.

FYI: Dont buy bearings for alternator or tensioner just buy the whole thing, it's easier and cheaper. I've heard of people trying to change just the bearing

Jaime-Corvette

Installed my belt yesterday and left car on for a while. Revved it up a few times. I did a 40 minute drive to test it... no chirp. My problem was only the belt.
goodluck with your problems guys!!

Pir8Diver

Nice!!! Which belt did you replace? We only replaced the drive belt and the chirp/squeak came back after 90 miles. Still goes away after water is sprayed on the grooved side of the belt. The noise is annoying (we are a little OCD and any rattle/squeak in a car makes us crazy!) so I just need to find time to determine the true cause & get it fixed.

Jaime-Corvette

just the serpentine drive belt. Have you used any tool to listen to where exactly the noise is coming from? It could be a bearing or a pulley. It also wouldnt be a bad idea changing the ac belt either

Pir8Diver

The cause of the noise: the harmonic balancer. Seems this is a common issue (probably a poor design in the part).

Jaime-Corvette

so you've found it. Yes harmonic balancer are known to go bad on corvette. Well that is the worst thing that can happen and if you are changing it once and for all dont buy an oem one... it will happen again.
spend a little more for an aftermarket one and never dea with it again. Goodluck with your problem.

ImBoosted

Don't post often, but for added info and for those that will one day research a similar issue:

If you can't locate a problematic belt, tensioner/idler, accessory unit: I believe it's the harmonic balancer. My 06 C6 was making a similar chirping sound intermittently and my balancer appeared to very slightly wobble - less so than your video. I initially thought it was due to cleaning my engine bay, because the noise became apparent 1-2 days after I cleaned. The wobble I witnessed with my HB didn't seem significant and was no where near as pronounced as other examples of problematic HBs I researched on different forums/online, so I didn't believe it was the problem as many have discussed that a slight HB wobble is normal. Car was at about 35K miles. Lubricating my belts made the noise go away - I replaced both belts, which were in great shape. Noise returned, but I was unsuccessful in locating the source. The tight engine bay made it a bit difficult. I thought it may be coming from the AC tensioner, but was unsure. I planned to replace it. The noise became louder upon start-up one cooler morning. I shut the car off and noticed the HB had walked forward slightly, but nothing was damaged. Car stayed parked until I repaired it.


If you have a similar issue and cannot locate a source, check your harmonic balancer. If it is wobbling and/or loose and requires replacement. DO NOT START YOUR ENGINE. Some forum members have had significant damage due to a failing HB/bolt. Most talk has been that this issue involved 2005 models, but its apparent that that is not true as many other year models have had the same problem.

1. Replace/repair with a new bolt + high-temp/strength threadlocker and even pin your crank if you wish or will be going SC in the future. I went with an upgraded 25% underdrive pulley.
2. Install new HB with an installation tool or drive with an aluminum/wood block that fits into the recessed portion of the damper as to not damage the damper.
3. Use old bolt to tighten to 240 lb/ft - be sure damper is seated. Remove old bolt.
4. Apply threadlocker to new bolt.
5. Tighten new bolt to 37 lb/ft.
6. Tighten bolt with a second pass to 140 degrees.

GM bolts should be used only once. OEM bolt P/N I used: 122557840
Threadlocker should be high temp/high strength. Loctite 272 or similar.
ARP bolts can be reused and have slightly different torque specs depending on if you're using threadlocker, assembly lube, nothing..etc. ARP P/N: 234-2503
If using UD pulley - 25% underdrive pulleys require a shorter main belt - 78" (6 rib). P/N I used: Dayco 5060780. Similar belts will work. Factory belt length is 80". AC belt should be the same length as factory.
You can use this opportunity to replace other pulleys, timing cover seal, install a cam..etc.

Link to post describing how to get to damper: https://www.corvetteforum.com/forums...post1570884721