Mystery chirp while under acceleration?

Tiny
OUTTATOWN
  • MEMBER
  • 2002 PONTIAC GRAND PRIX
  • 3.1L
  • V6
  • 2WD
  • AUTOMATIC
  • 183,000 MILES
I have the car listed above that had an exhaust leak for 2 years. I replaced the exhaust from the manifold back and welded all exhaust seams. From there on out I’ve had a mysterious chirping sound under acceleration. I have tried day in and day out to find where the chirping sound comes from, but I’ve been unsuccessful any advice or thoughts would be great thanks!
I’ve changed the oil added trans fluid didn’t do anything.
No mix of coolant or oil.
No metal shavings.
No loss of power or misfires.
Sunday, March 26th, 2023 AT 5:16 PM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,940 POSTS
This sounds like you have a serpentine belt tensioner or idler pulley that has gone bad but to be sure please remove the serpentine belt and start the engine for a second to see if the noise goes away if so, spin the accessories and pullies to see which one is making noise. Also, if the belt is worn it can cause the problem as well. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.
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Monday, March 27th, 2023 AT 9:36 AM
Tiny
OUTTATOWN
  • MEMBER
  • 3 POSTS
Hey Ken, sorry it’s been a minute I lost my account and lost faith in the car itself; I’ve taken off the belt and ran the car around the lot still has the chirp under acceleration. I know this isn’t the best method but at this point I’ve beaten the car praying that weak link will break and shoe itself but 6 months later and it still chirps, and nothing breaks. Any ideas? I’ll try uploading videos and pictures. Thank you for your time!
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Saturday, November 4th, 2023 AT 7:13 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,940 POSTS
Does the noise change when you put the car in gear and then into neutral, also is the noise coming from the rear of the engine? If so, it sounds like you have a bad flex plate which sits between the engine and transmission, to be sure can you please shoot a quick video with your phone so I can hear the noise? That way I can tell what's going on. You can upload it here with your response.
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Sunday, November 5th, 2023 AT 11:27 AM
Tiny
OUTTATOWN
  • MEMBER
  • 3 POSTS
This is the best video I can get it’s the high squealing sound at higher RPMs.
The only thing I can add from here is there is still no engine code, at first the noise only happened under acceleration now I can get it to make the noise in park revving the motor, so I believe maybe internal parts I’m unsure. All fluids are good no metal shaving no mixing of fluids.
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Tuesday, November 7th, 2023 AT 4:09 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,940 POSTS
Thanks for the video it helps. It sounds like a serpentine belt tensioner pulley bearing or the serpentine belt needs to be replaced. To be sure let's remove the belt to check its condition and to spin the pulleys to see if you can duplicate the noise. Once the belt is off, start the engine to see if the noise is still there when the engine is revved.
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Wednesday, November 8th, 2023 AT 9:00 AM

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