alternator whine, belt squeal

I was told this Rodeo had a bad water pump, but the problem is the alternator instead. As soon as you start it, the belt squeals, and smokes very badly. If I unplug the alt, it goes away. Seems like a short in the wiring harness, but I can't find any burned / hot wires. I've put 3 different alternators in this, and swapped the ecm, thinking it was demanding an overcharge for some reason. Anyone else run into this before?

Sounds like the belt needs to be tighter.

That was my first thought, but in the course of putting three in you'd think it would have been tensioned properly once.

That was my first thought, but in the course of putting three in you'd think it would have been tensioned properly once.
You'd think, but if the little tensioner bolt is missing or busted you may have trouble getting it tight enough.

That was my first thought, but in the course of putting three in you'd think it would have been tensioned properly once.



The alternator belt has to be pretty tight or it will slip. Tighter than what most mechanics would consider good enough. I had the same slipping problem until I tightened the belt tighter than what I thought it should be.

Same with mine. I'm constantly tightening that belt to eliminate the startup squeal.

OK, I will try adding more tension to the belt. Does anyone know, is there a deflection spec for this, or just tighten it until it stops making the noise?

OK, the belt is REALLY REALLY tight now, but it is nice and quiet, and the alt is charging well. Now it's so quiet, I can hear the timing belt idler rattling. Thank you all for your advice.

Good deal. Shortly after (over?)tightening the steering pump belt once, I lost it. I guess it's overkill to keep a spare with you since there are 3 belts and a different way to adjust each.

OK, the belt is REALLY REALLY tight now, but it is nice and quiet, and the alt is charging well. Now it's so quiet, I can hear the timing belt idler rattling. Thank you all for your advice.



Well, thats the tricky part. If you overtighten a belt, you run the risk of wearing out bearing and stuff. You might want to play with it a bit and get it as loose as possible without it squealing. A pain, I know, but it could save your alternator from having to be replaced.