Car alternator belt squeals or is it the alternator itself

Discussion in 'The Garage' started by VinylxScratches, Mar 15, 2011.

  1. VinylxScratches

    VinylxScratches Golden Member

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    I have had this issue for 6 months but it being cold, never bothered to try to fix it since the car still runs.

    What I turn the car on, the alternator or alternator belt squeal.

    Things that make the squealing noise.

    Front lights, break lights, heat, windshield whipers, leaving the car in drive at a red light, back window heater.

    Things that stop squealing noise.

    Turning lights off, putting the car in neutral, letting go of breaks in neutral, turning off the back window heater. Putting the car in neutral and slamming the gas seems to stop it too.

    I also notice a chirping noise when the car is idling. It doesn't do it when it's in drive.

    I changed the belts a while back....

    Any ideas?

    The car is a 2002 Dodge Neon with about 98000 miles.
     
  2. pcgeek11

    pcgeek11 Diamond Member

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    It could be the belt or idler pulley bearing. It does this due to the electrical load placed on the alternator: The bigger the load the more drag on the belt.
     
  3. MagnusTheBrewer

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    Belt tension is improperly adjusted.
     
  4. LTC8K6

    LTC8K6 Lifer

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    The more stuff you turn on, the harder it is to turn the alternator.

    You are going to have to get under there and listen and try to pinpoint.

    Chirping would make me think of a pulley or bearing.
     
  5. exdeath

    exdeath Lifer

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    Pull belts off, drive up and down the driveway, see if problem goes away. Play with all the pulleys by hand, see if any feel sticky or gritty or have any end play. Much easier to troubleshoot when it's cold out, like 30-40 F cold and you can feel the grit better in the offending pulley.

    And yes, the alternator has it's own bearings inside, they are typically replaced along with the brushes/regulator and rectifier when performing a refurb.

    Electrical load is inconclusive, as it affects engine RPM and thus could still be any pulley and not just the alternator.
     
  6. pcgeek11

    pcgeek11 Diamond Member

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    Most have auto adjusters.
     
  7. 5150MyU

    5150MyU Senior member

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    Your belt isn't tight enough-spray a little water on it when it is chirping to verify.
     
  8. 5150MyU

    5150MyU Senior member

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    The alternater belt is not self tensioning on that vehicle--if it has been slipping bad you may need to replace it again though unlikely.
     
  9. bruceb

    bruceb Diamond Member

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    Given that mileage and that you have replaced the belt, I would suspect the alternator bearings are going bad. It may soon need to be overhauled as brushes in the alternator wear down with time and as such, the charge output starts to drop. I would consider rebuilding or replacing the alternator soon.
     
  10. SuperSix

    SuperSix Elite Member

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    "Hey! Let's overthink everything!"

    Check the belt, make sure it's tight, then start thinking it's everything else.

    Did it do it before you changed the belt?