Belt or Alternator? Or something else?

[jskwise]

I usually just Google and read everyone elses problems on forums, but I'm in need of some more specific assistance today- hopefully this is the place for my answers.

I've got a 1999 Explorer XLS 4.0L V6 with 160,000 on it. It runs great- except for one issue. The belt has been loud, and getting louder. After the engine had begun running horribly, and the belt waking up the neighborhood, I took it to our mechanic who replaced the belt. The squeak started right back up again, and when I popped the hood I'd discovered that it was coming off the pulleys and there was a lot of play. So I went to Autozone and bought another belt and replaced the belt and tensioner myself.

Things were okay for a few days, now it's started up again. It does squeal in line with RPMs, etc.

What's more, though, is that the entire electrical system seems to be acting up with it. As mornings have been getting colder, it's been worse, too. The headlights, dash lights, radio, all dim and get brighter in line with the RPMs and squealing- which leads me to believe that it may be the alternator bearings that are causing the whole situation.

Any thoughts on this? I'd appreciate any help I can get. I've already sunk $150 into it, but I'd like to get to the bottom of this before this belt is shot too.

Thanks!!

 

[turboplz]

Most likely the alternator bearings and brushes are going out. Try taking off the alternator and going to autozone or advance and have them test it out for you.

 

[jskwise]

I called Autozone, and they said they can test it while it's in the engine, but it may not be accurate. Do you definitely recommend taking it out to take it?

 

[swshawaii]

Remove the belt and check ALL the pulleys.

 

[jskwise]

Sorry- I'm fairly new to working on my own vehicle. What exactly am I checking them for? Just want to make sure I'm thorough.

 

[turboplz]

You can do a quick, rugged check to determine where the squeal is coming from. Just get yourself a couple socket extensions together and with the engine running, put one end of the extensions on the suspected culprit and the other to your ear. The squealing should be a bit louder through the extension and into your ear when you find the squealing culprit. You just need to place the extension on the part, not the pulley, to hear the sound.

As for testing the alternator, I would remove it to have them check it. I would want the test being performed to be as accurate as possible.

 

[my98nnj]

Remove the belt, you've already done this so it should be easy.
Spin all of the pullys by hand, you'll feel the one that's causing the noise.
Replace that component and you should be all fixed.

 

[01STrunner]

I have the same problem. I think I've narrowed it down to the P/S pump because if I spray silicone grease on the pulley the noise goes away for a little but comes back. Ive taken the belt off a couple times and cleaned it. The noise went away then too but soon came back. Only thing is I took the P/S pulley off the pump and nothing felt out of whack and everything turned ok. Any thoughts?