Bad engine squeal when accelerating

Tiny
CHEVYJAMES1970
  • MEMBER
  • 2002 CHEVROLET TRAILBLAZER
  • 4.2L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 250,000 MILES
It is not the belt. Replaced everything on the front of the engine, tensioner and pulley, idler pulley, water pump, fan clutch, noise still there! Removed belt and drove, squeal still there. Sounds like coming from front of the engine. Searched for vacuum leaks, nothing.
Friday, December 20th, 2019 AT 9:15 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

That's an interesting one. Tell me. Do you only hear it when you accelerate the vehicle or can you get it to do it when you are in park and rev the engine?

Is it possible for you to record the sound and upload it for me to hear?

Let me know.
Joe
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Friday, December 20th, 2019 AT 9:49 PM
Tiny
CHEVYJAMES1970
  • MEMBER
  • 3 POSTS
Only when accelerating, hits the rev limiter before it will do it in park, put it in gear and power stall it and it will do it. Evidently has to be a load on it. I thought maybe transmission, but the noise is coming from the front of the engine.
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Saturday, December 21st, 2019 AT 5:56 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
I wonder if there is a broken motor mount allowing the engine to shift far enough causing something to happen. Does it do it in both drive and reverse? I ask because the engine torque will cause the engine to shift in different directions based on the gear. Simply open the hood, start the engine and place it in drive. Place foot on the brake and gently press the throttle to see if the engine is moving more than it should. Do the same in reverse.

Also, have a helper there with you and have them listen if it could be coming from the bell housing area on the transmission.

If possible, record it so I can hear it.

Let me know.
Joe

Let me know
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Saturday, December 21st, 2019 AT 7:19 PM
Tiny
CHEVYJAMES1970
  • MEMBER
  • 3 POSTS
The noise ended up being a whistle instead of a squeal. It was exhaust coming from around the manifold. The catalytic converter was plugged, replaced the converter and now runs great and no noise!
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Monday, January 13th, 2020 AT 8:11 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Wow, it must have been totally plugged. Regardless, I'm glad to hear you got it fixed and running properly again. Feel free to come back anytime you have questions in the future.

Take care of yourself,
Joe
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Monday, January 13th, 2020 AT 7:19 PM

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