Alternator

Tiny
THOMASSTURGILL
  • MEMBER
  • 2005 CHEVROLET TRAILBLAZER
  • 4.2L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 75,000 MILES
I have this intermittent rattle noise coming from the front of the motor. Just replaced the alternator clutch fan and water pump. If I put a piece of metal to the alternator I can hear it and feel it. If I do the same thing to the block and all the other components no noise. Also, the noise goes away when I remove the serpentine belt.
Saturday, January 20th, 2018 AT 3:38 PM

13 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good morning.

Have you replaced the alternator as a unit or just the front section?

If you spin it by hand, can you hear the noise?

Roy
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Sunday, January 21st, 2018 AT 4:51 AM
Tiny
THOMASSTURGILL
  • MEMBER
  • 8 POSTS
The shop put a GM re-manufactured full replacement. The has a slight tight spot when belt is off and rotating by hand. When I place a metal rod along the block and all the other pulleys I have no noise but it is really loud in the alternator and really low sounding around it.
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Sunday, January 21st, 2018 AT 5:23 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Okay, good chance the new alternator is no good. Have you spun the power steering pump, AC clutch, tension-er pulley and idler pulley?

Roy
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Sunday, January 21st, 2018 AT 5:30 AM
Tiny
THOMASSTURGILL
  • MEMBER
  • 8 POSTS
All are good I have had the harmonic balancer replaced with the updated version. The noise is only there during idle and not under-load.
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Sunday, January 21st, 2018 AT 6:56 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Okay, then it sounds like you have a bad new alternator.

Roy
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Sunday, January 21st, 2018 AT 6:59 AM
Tiny
THOMASSTURGILL
  • MEMBER
  • 8 POSTS
Okay thank you so much for the information. I have an appointment Tuesday to get it changed.
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Sunday, January 21st, 2018 AT 7:26 AM
Tiny
ASEMASTER6371
  • MECHANIC
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You are welcome.

Roy
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Sunday, January 21st, 2018 AT 7:27 AM
Tiny
THOMASSTURGILL
  • MEMBER
  • 8 POSTS
I just removed my belt and the alternator pulley has a squeak to it.
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Sunday, January 21st, 2018 AT 8:09 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
That is not good. Should be making no noise at all.
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Sunday, January 21st, 2018 AT 8:10 AM
Tiny
THOMASSTURGILL
  • MEMBER
  • 8 POSTS
Okay.
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Sunday, January 21st, 2018 AT 8:14 AM
Tiny
THOMASSTURGILL
  • MEMBER
  • 8 POSTS
Well got the alternator switched out and the problem is fixed.
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Tuesday, January 23rd, 2018 AT 10:31 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Nice job. We even get fooled by bad new parts

Roy
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Tuesday, January 23rd, 2018 AT 11:58 AM
Tiny
THOMASSTURGILL
  • MEMBER
  • 8 POSTS
Yes we do and thank you for the info.
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Tuesday, January 23rd, 2018 AT 12:43 PM

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