Alternators burning up on my 1985 Silverado

Discussion in 'GM Electrical Tech' started by Royce Lancaster, May 29, 2012.

  1. Everything was fine last night, this morning when I was leaving for school the alternator belt came off and got cut up by the fan. I'm not sure if the alternator is getting hot and breaking the belt or if it just wasn't tight enough and it popped off and got cut up.. So after I get out of school today I guess I'll try another shorter belt...
  2. RallySTX

    RallySTX Member 100 Posts

    Better break out the yard stick or alignment tool, and have a look at those pully's. Give that alternator drive pully a close look, and see if you can find rubber buildup on it. Look at the bad belt, and see if you can find areas where it was worn down or stretched. YYou're looking for why it came off. Double check all the fasteners for the fan and power steering pullys, just to be sure everything is tight. Looks like you have a massive short happening somewhere. I had a battery cable shorting against an exhaust header once, caused a nice fire too. Check the harness where it goes through the firewall, and that connector. Try disconnecting the extra stuff on the truck one part at a time, and keep doin g it until you eliminate the issue. Then if that fails, start pulling fuses from the box, until you find the one with the short. I would spring for new battery cables made with 02, or 01 welding wire for top shelf reliability. Sometimes those mass produced pieces are junk.
    Brian L.
  3. Im Looking into the alignment right now, Im gonna try disconnecting things again even though I found nothing last time i did it.


  4. I Found that the alternator was slightly out of line, fixed it. Also looking into adding another battery and an Isolator.

    Right now the alternator is working fine and doesn't appear to be burning the belt.
  5. RallySTX

    RallySTX Member 100 Posts

    Brian L.
  6. Well guys, the problem is back.. another new alternator after the regulator went out on the other one.
  7. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Royce, you must be running it into an open load.

    Recheck ALL connections. there must be a poor connection (battery, or ground) somewhere on the truck

    Or, a short?
  8. Once again the problem was the belt.. still doesn't make sense to me, but anyways its fixed. Now since I can't leave my truck alone does anyone know where i could find a dual alternator bracket for my truck?
  9. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Be assured, the problem is not the belt. Belts DO NOT burn out regulators and alternators.

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