Alternator belt squeaking sound

Tiny
IMAGING
  • MEMBER
  • 2005 TOYOTA SIENNA
  • 3.3L
  • V6
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
Vehicle was squeaking every time the ignition went on. Decided to replace the alternator belt. When inspecting the old belt, it's still was in good shape. But the squeaking noise continued. Should I loosen all the bolts and start again? And if yes, what are the torque specs for each bolt.
Friday, January 21st, 2022 AT 3:15 PM

8 Replies

Tiny
SQM
  • MECHANIC
  • 6,383 POSTS
Hello,

If the belt does not have proper tension, it can make the noise.

Also, the noise could be from the pulley as well. Make sure that the noise is not pulley related.

I have attached all the torque specifications below.

Please let me know if you have any questions.
Thank you.

https://www.2carpros.com/articles/replace-serpentine-belt
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Friday, January 21st, 2022 AT 5:50 PM
Tiny
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How can I inspect the pulley to know it's not the pulley?
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Friday, January 21st, 2022 AT 6:15 PM
Tiny
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The best way to do it is to use an automotive stethoscope and hold it on the hub of the pulley. This way you are not guessing.
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Friday, January 21st, 2022 AT 6:17 PM
Tiny
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Where is the hub of the pulley? Can you show me a picture of how to do it?
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Friday, January 21st, 2022 AT 6:22 PM
Tiny
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Now, if it is the pulley, won't it just continue squeaking thru the whole ride and not just at ignition start for 5 seconds?
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Friday, January 21st, 2022 AT 6:26 PM
Tiny
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Yes, typically the pulley will keep squeaking as the engine is running and not just on start up.
First torque those bolts to the specification for the tensioner pulley and let me know if that fixed the issue.
It is probably a good idea to loosen them and retighten the bolts.
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Friday, January 21st, 2022 AT 10:48 PM
Tiny
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In diagram 4 (A/C belt), it shows bolt 'B' as the tensioning bolt but in diagram 5 it shows bolt 'C' as the tensioning bolt. Then it shows in diagram 4, bolt 'A' below the tensioning bolt but in diagram 5, it shows bolt 'A' on the top.
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Friday, January 21st, 2022 AT 11:53 PM
Tiny
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I don't see those anomalies on the diagrams as you are stating.
The bolt B is the tension bolt. Bolt A secures bolt B

You first loosen the bolt A and C to adjust bolt B. Then tighten the A and C. This will keep the bolt B from moving.
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Saturday, January 22nd, 2022 AT 10:38 AM

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