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Squeeky belt on jeep

Discussion in 'Truck & Equipment Repair' started by plowjeep420, Feb 15, 2010.

  1. plowjeep420

    plowjeep420 Junior Member
    Messages: 11

    :help:Jeep is a 94 YJ inline6 with auto trans, noA/C. New belt, and the only times it squeeks is when the alternator is being hit with lots of amps, for example off road lights, plow pump, highpower reverse lights ect.. not all at once, but any one of the above.. My question is: Is this squeek a sign that I will need a new alternator soon?:help:
  2. theplowmeister

    theplowmeister 2000 Club Member
    from MA
    Messages: 2,617

    1 bad alternator
    2 bad idler pulley
    3 bad tensioner
    4 polished pulleys (you know from having a loose belt on it for a long time).
    5 cheep belt that stretches.

    O ya does the fan belt have an auto tensioner? If NOT it might be LOOSE or see #3

    I love it, have you opened the hood and listened to it, narrowed the search down? You haven't said so.

    Sorry for venting...
  3. plowjeep420

    plowjeep420 Junior Member
    Messages: 11

    Yes, I have opened the hood and I am 100% that the squeek is coming from the alternator, the belt has proper tensioning, and is a new belt (Gates). Again the only time it squeeks is when I use the plow pump, or put it in reverse with the 2, 55watt spot lights on, or when I turn on the 2, 100w roof lights. I am pretty sure this alternator was replced at 30,000 miles (39,000 miles ago), and I think it is a high output alternator. I have already ordered a new high output alternator. Big question is about how much longer will it last? Hopefully none of my clients neighbors will shoot me!!
  4. overtime

    overtime Senior Member
    Messages: 153

    Sounds like its the alt. Up a long screw drive on it and see where its louder. Or put a stethacope. (Howerver its spelled)
  5. plowjeep420

    plowjeep420 Junior Member
    Messages: 11

    MEAN GREEN should be here by noon wednesday, however its snowing now!
  6. the_experience

    the_experience Member
    Messages: 75

    I know it's too late now, but I really like the Dayco W-profile belts with the p-aramid fibers. They're designed to be strong, but very quiet. The tensioner on the 4.0 is pretty rinky dink...
  7. plowjeep420

    plowjeep420 Junior Member
    Messages: 11

    Mean Green Alternator

    Well it has been a week since I ordered my mean green alternator, with next day shipping, and it is here now. Because of snow I had to get the jeep back on the road, so I purchased a NAPA $90 alternator. The NAPA alt puts out 63 amps at idle, and 138amps at 5000rpm The NAPA alt did stop the squeak at first, however after plowing for about 2 hours, the NAPA alt started to squeak when the plow was activated with the driving and head lamps on. If I rev up the engine, when I use the plow I have no squeak. The belt is tensioned correctly. Today looks like I will have time to swap the mean green alternator into the jeep. I will use the NAPA alternator as a back up
  8. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Are you sure the tensioner is good? (If it has a serpentine belt?) The added rotational resistance when it's putting out high amps may be letting the belt slip. The pulley's working surface may have a high polish to it too.No spacer's or washer's missing from the mounting bolts?
  9. green frog

    green frog Senior Member
    Messages: 246

    I had the same problem with my cherokee and plow set up. I just tightened the belt 2 full turns and no more noise. I know its a little tighter than spec but has been good for last 10k.
  10. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Find the release on the lower dash for hood. If it does not work have someone pull up on hood when you use release. No helper? Use a wood wedge jambed in to lower edge to raise hood up. After it pops to safety catch, find release catch on core support area.
    Or if it's a classic jeep release the two external catches on each side of hood.
    In case your trying to be funny. This is NOT an unregulated / wide open forum. There are many, many professionals here to help. Keep it clean and R-rated.
    Last edited: Jan 11, 2013
  11. hatefulmechanic

    hatefulmechanic Senior Member
    Messages: 228

    You may want to look into adding more reserve capacity in the form of a secondary battery, to help cope with the additional load.

    Also, take a good look at the crank pulley, the balancer likes to slip the rubber causing noise on occasion as well.
  12. LEVE

    LEVE Member
    Messages: 79

    I'm going out on a limb here and assuming. I assume that this belt squeak has just started recently. The alternator can be having a problem with handling the higher amperage loads. It may, however, not be the problem.

    Have you checked grounds? On a Jeep YJ there are really three ground circuits:
    • Battery to engine block
    • Engine block to frame
    • Frame to tub
    If any of these grounds are compromised then the ground circuit can become resistive. That wastes energy meant for the devices.

    The YJ also uses the frame for a grounding bar. That can be problematic over time as the riveted joints in the frame loosen over time and they become resistive.

    May I suggest making sure the alternator case is well grounded to the engine block, and that the other grounding wires are clean, free of corrosion, etc.?

    You may even need to run separate grounding wires to each of the devices. Me, I'm a fan of nice huge grounding bars on a Jeep CJ, or YJ. These help to insure that your electrical system won't suffer grounding gremlins.
  13. gafred

    gafred Member
    from Boone
    Messages: 36

    When the belt squeeks, run a stick of chalk agains the grab side of the belt if it stops somewhere along its journey loosing grip. loose tensioner, belt to long, belt low quality rubber, pulley mis alignment.
  14. gafred

    gafred Member
    from Boone
    Messages: 36

    run a ground wire from battery to alternator case to body, around 6 gauge.
  15. theholycow

    theholycow PlowSite.com Addict
    Messages: 1,180

    That's a long limb...it started 3 years ago and I imagine it was fixed shortly thereafter.