I think spraying or pouring a little water on a belt is a better idea than WD-40.
Still chirping
Thread Starter
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
Still chirping
2007 base, A6, Z51, 27,000 miles:
I replaced the harmonic balancer with an ATI unit and replaced both belts with AC Delco. All pulleys felt fine. Seemed to have grease in them and rolled smoothly.
When I start the car, hot or cold, it is silent for about 5 seconds and then I get a loud chirping for about 15 seconds. After that it is chirping but not as loud. It also seems to go away completely for a few seconds every once in a while. Everything looks like it is lined up properly. No wobble anywhere.
Is there any way to isolate where the noise is coming from without just replacing pulleys? I have been told to spray the pulleys one at a time with WD40 and when it quiets the chirp I will have found the culprit. Spraying the belt/pulley area with WD seems wrong to me. If that is the way to do it, let me know. I wanted to check in here before I did anything stupid. Any suggestions would be appreciated.
I replaced the harmonic balancer with an ATI unit and replaced both belts with AC Delco. All pulleys felt fine. Seemed to have grease in them and rolled smoothly.
When I start the car, hot or cold, it is silent for about 5 seconds and then I get a loud chirping for about 15 seconds. After that it is chirping but not as loud. It also seems to go away completely for a few seconds every once in a while. Everything looks like it is lined up properly. No wobble anywhere.
Is there any way to isolate where the noise is coming from without just replacing pulleys? I have been told to spray the pulleys one at a time with WD40 and when it quiets the chirp I will have found the culprit. Spraying the belt/pulley area with WD seems wrong to me. If that is the way to do it, let me know. I wanted to check in here before I did anything stupid. Any suggestions would be appreciated.
Le Mans Master
Joined: Oct 2000
Posts: 6,507
Likes: 722
From: Sausalito CA
Well you can try using a stethoscope to listen.
I have done the WD40 technique myself with no ill effects.
Could be oily residue on the pulley groves so the belt is slipping...contact cleaner and wire brush all the pully grooves.
Or a tensioner or belt pulley quide is bad even though they felt OK.
Good hunting.
I have done the WD40 technique myself with no ill effects.
Could be oily residue on the pulley groves so the belt is slipping...contact cleaner and wire brush all the pully grooves.
Or a tensioner or belt pulley quide is bad even though they felt OK.
Good hunting.
Thread Starter
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
Le Mans Master
Joined: Dec 2005
Posts: 6,999
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From: Southeast TX
Try to simulate a side load on each individual pulley. Put the belt on each pulley individually and pull back and forth. Even a pulley with a bad bearing will sometimes spin freely and quietly spinning it with no side load.
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2007 base, A6, Z51, 27,000 miles:
I replaced the harmonic balancer with an ATI unit and replaced both belts with AC Delco. All pulleys felt fine. Seemed to have grease in them and rolled smoothly.
When I start the car, hot or cold, it is silent for about 5 seconds and then I get a loud chirping for about 15 seconds. After that it is chirping but not as loud. It also seems to go away completely for a few seconds every once in a while. Everything looks like it is lined up properly. No wobble anywhere.
Is there any way to isolate where the noise is coming from without just replacing pulleys? I have been told to spray the pulleys one at a time with WD40 and when it quiets the chirp I will have found the culprit. Spraying the belt/pulley area with WD seems wrong to me. If that is the way to do it, let me know. I wanted to check in here before I did anything stupid. Any suggestions would be appreciated.
I replaced the harmonic balancer with an ATI unit and replaced both belts with AC Delco. All pulleys felt fine. Seemed to have grease in them and rolled smoothly.
When I start the car, hot or cold, it is silent for about 5 seconds and then I get a loud chirping for about 15 seconds. After that it is chirping but not as loud. It also seems to go away completely for a few seconds every once in a while. Everything looks like it is lined up properly. No wobble anywhere.
Is there any way to isolate where the noise is coming from without just replacing pulleys? I have been told to spray the pulleys one at a time with WD40 and when it quiets the chirp I will have found the culprit. Spraying the belt/pulley area with WD seems wrong to me. If that is the way to do it, let me know. I wanted to check in here before I did anything stupid. Any suggestions would be appreciated.
Race Director
Joined: Aug 2005
Posts: 13,592
Likes: 187
From: Hudson WI
NCM Sinkhole Donor
I had that noise on another car and it was the water pump.
Take the belt off and see how the water pump turns.
Once I got it off the car the water pump was so tight, I could hardly turn it. I was surprised the belt hadn't broke!
Take the belt off and see how the water pump turns.
Once I got it off the car the water pump was so tight, I could hardly turn it. I was surprised the belt hadn't broke!
Last edited by timd38; Oct 31, 2014 at 04:43 PM.
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Thread Starter
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
I tried water on the belts and it did not change. It is a strange thing. Silent after start up for the first 5 seconds or so, then very loud for another few seconds. After that, it is not very loud but definitely noticeable. I can hear it inside the car but I am listening for it. When I rev the engine a little it gets a little louder like the belt is slipping for a second or two and then goes back to a lower chirp. It also sounds like it is coming from the drivers side. Maybe I should just replace the three pulleys and see what happens.
Thread Starter
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
Noise is still there. No change. I will take the belts off again and see if I missed something. The noise has been there for a long time (at least 4000 miles) with no changes. I have replaced the balancer and belts and it is still the same noise. No better. No worse. Had the belts off and checked all pulleys a couple of weeks ago and everything seemed smooth. I will do it again. The chirp is annoying and must be a sign of something going away but it has not become any worse. And the complete silence for the first five seconds or so after start up that gets very loud immediately thereafter is bizarre. That start up silence, loud chirp to moderate chirp is very consistent.
Thread Starter
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
I was not clear there. Without belts, the noise is gone. I am just trying to see if there is a way to pinpoint which pulley or accessory is making the noise. Not having any luck so far. Worst case is I will just start by replacing the idler pulleys.
Thread Starter
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
Thank you all for the help.
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 462
From: Southern Utah
Another thought...the speed of the chirping should be noted also. Normally chirping from the belt goes at the speed of the belt...once per belt revolution. A chirp from a pulley should go at once per rev of the pulley, which would be maybe 6 or 8 times as fast as the belt revolves. Might help diagnosis. And even a really good automotive stethoscope will be less than half of the price of one pulley.
Also, you might try pulling the belt off and turning it around 180 degrees. What the heck...
Also, you might try pulling the belt off and turning it around 180 degrees. What the heck...
Thread Starter
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
The ATI unit I installed is part #ATI-917246 H/P 7.5 Super Damper Serpantine Series, Internal balance, 7.530" O.D.