Does this sound like a bad fan clutch?

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by bettingsumo, Nov 8, 2013.

  1. bettingsumo

    bettingsumo New Member

    Hello everyone! I have a noise I need some help identifying. Took the video below so you could hear it. This is from my 1999 Suburban K2500 7.4L. My first guess is a bad fan clutch, but I am not sure as this is my first time dealing with that. Anything else it could be? The noise comes at startup for a minute or two then typically goes away only to reappear every so often while I am driving.
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    You have a bad pully bearing, ps pump, alternator, or waterpump. I would pull the belt off and spin the pullys by hand listening and feeling for a crunchy or squeak.
  3. bettingsumo

    bettingsumo New Member

    OK, I pulled the belt and spun everything. Everything seemed to spin pretty freely, the only noise I could hear was from the alternator. Here is a video of the alternator turning:
  4. estrom

    estrom Rockstar

    Something to try if you cannot identify the issue using Pikey's suggestion. While it's running, take a 2-3 foot long piece of hose or some other type of tube apparatus. Hold one end to your ear, and move the other end around to each pulley. Sometimes this will help specify where the sound is originating.
  5. bettingsumo

    bettingsumo New Member

    So I took the belt off and spun everything, but could not really replicate the sound. The only place I could hear any sort of noise was coming from the alternator. There is a video below, please tell me what you think.

    I am just curious, if it was the alternator bearings would I hear the sound all the time? The fact that the noise is intermittent confuses me, because it seems like it should come from something that cycles on and off... No? Or is it possible that the alternator bearings are just starting to wear funny and only make the noise when they happen to fall in a certain position....

    estrom: sounds like an good technique to isolate the sound. Not sure how I can (safely) reach some of those pulleys while it is running, but worth exploring. At the very least I should be able to listen in on the alternator.
  6. BQS4

    BQS4 New Member

    If you haven't put thw belt back on, I'd check the water pump. Grab the fan at the center and try to see if you have any movement on the shaft side-to-side
  7. Guardrail

    Guardrail Member

    The noise could be intermittent because as the different accessories demand draw, the belt tension changes. Try turning the AC on and off to see if the noise comes and goes. When the AC clutch engages, it will put a different tension on the belt.
  8. BurbanMan

    BurbanMan Rockstar 3 Years 500 Posts

    Sounds like the alternator shaft bearing has gone south. Mine has done this as well. Is there a way to replace it without buying a new alternator
  9. bettingsumo

    bettingsumo New Member

    I looked into just replacing the bearing and while it is an option the time and effort doesn't seem to make sense as the brushes and all will probably fail sometime in the not too distant future anyways. I think just replacing the whole alternator is the way I am going to go.
  10. bettingsumo

    bettingsumo New Member

    Finally got around to replacing the alternator. Unfortunately the sound is still there. Typically I hear it 80% of the time when I start up and then it stops after 1-2 min. On very rare occasions it will make the noise while I am driving, but no matter what I try turning on or off (AC, etc...) it makes no difference.

    Mildly annoying, but very frustrating

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