A few months ago I replaced all my belts and ac compressor. Now the alternator belt is squealing and I can't get it to stop. I've tightened and pulled as much as I could and even used belt dressing to quiet it down. that worked for a day. Not its ridiculous. Its even worse, just starting off the line or at idle with the heat or defrost on. turn that off and its somewhat better.

Is this telling me my alternator is going or is it the belt?

Thanks
Bob

 

possible it is your alternator and possible that you have the belt too tight

an autoparts shop should be able to test it for you. When you turn on the high amp draw items do you notice your output dropping on your voltmeter?

 

Thanks OC. I'm starting to realize something. I just ran to the bank and home to get lunch, heater on and no squeal. I'm going to test when I leave work and turn on lights and heater to see if thats it. If it does squeal then I'll know its the alternator.

 

Ok, thinking its the Alternator. Everything was fine this morning. Drove around with heater on and it was quiet. Left for work tonight, had the heater and headlights on, when I took off from stop lights, it would squeal or when I was slowing down.

Sound right?

Bob

 

Bob,

It "sounds" as if you have narrowed it down to the alternator area. Just curious though, how does the alternator pulley look? It may need a cleaning. You may want to give the belt ribs a visual inspection before plunking down some $$$ on another alternator.

 

I will when I can get it into a garage...little cold out to play with the engine, haha. While I was at a lite, I turned the heater on and my headlights dimmed noticibly.

 

could be the pulley?

 

Ok..did a few more test tonigth on the way home:
Headlights on, heater or defroster on: no squeal
Headlights on, heater or defroster on, stereo on (just a plain alpine headunit): little squeal
Headlights, heater or defroster, 3" round 55w PIAA lights on: little squeal
Headlights, heater or defroster, 3" 55w driving lights, stereo: squeals loudly

Does this tell me the alternator is going or its the pulley? I'm not sure what to think. I believe that its the alternator and the more draw I put on it the more it strains. I do see the headlights dim when everything is on and it squeals.

Thanks for all your help
Bob

 

You'll need dmm to measure voltage. Check the battery too. Sound like brush (inside of the alternator) might need to replace.

 

Have you tried a different belt like a Toyota( and checked the size)?

Could you have gotten grease or oil on the belt or pulleys?

As the alternator puts out more power( as you turn on more stuff) it gets harder to turn, and if it starts slipping (squealing)it might not be able to put out enough power just because of the slipping.

Have you checked the deflection on the belt to see if there really is the proper amount of tension on it?

Removel the belt and turn the alternator by hand and feel for rough bearing.

Unless your overloaded with aftermarket electrical suff the alternator should keep up with demand( no dimming lights with standard equipment on) unless it slipping.

If you have a ribbed pulley check in the groves for small stones, I have seen this causing slipping( and destroy the belt).

 

Had what sounds like the same problem a couple months ago. I originally noticed the squealing in low gears and couldn't find where from. Throughout the next two weeks it slowly, but progressively, became worse. I had figured out that is was the alternator belt didn't know much more as to why. Then it broke the following week as I was driving at 70ish mph. After replacing the belt, no more problems. Alternator was fine, pulleys were fine, and new belt hasn't had any issue. You may have it too tight but I don't pretend to be an expert whatsoever.

I'd keep a spare belt and tools in the truck to replace it if your stuck on side of road one day with no power.

Hope this helps.

97 runner

 

**UPDATE**
Took alternator off and took it to PepBoys to be tested. They said it passed under normal load. I haven't added anything else but repalcing the driving lights and they have been on there months before this started. the battery is a red top optimum battery that is only about a year old. I am still getting the squeal. I guess a new belt will be the cheaper way to start first. Anyone know how to make sure the belt is tight enough or get it tight enough?

I did notice one thing while looking over everything, a nut was missing off (1) and of the 4 bolts holding the fan to the idler. Is this something that could be causing it to squeal?

 

A nut on there may fix the squeal. However, it may be the bearing in the fan bracket is going causing the squeal. If so, the fan bracket is AISIN FBT-004 (you cannot get just the bracket from Toyota) and is available for about $105 from Mac Auto Parts in NY where several of us have bought from.

 

Link for the fan bracket:
http://saturn-car-parts.macautoparts...oductInfo.aspx

If I were to replace the belt, it would be with the OEM or Bando. You may have had a bad belt out of the box before. 90179-08123 for the nuts that hold the fan to the fan clutch. Torqued to 67 in/lbs.

 

By reading your original post, I strongly believe your alternator belt is the culprit.

If you put belt dressing on it and it worked for a day, but then got worse, you've found your problem.

Belt dressing is a weird animal. Did you apply it as the truck was running? If so, you'll experience that exact symptom. Goes away, comes back.

Try taking the belt off and applying belt dressing then. Let it dry, reapply, let it dry and then put it on the truck. If it'll ever help, it's then, but honestly, from my experience, belt dressing is more preventative than a fix it all.

There's two ways to test belt tension. The tool method (a belt tension gauge) which would have the specs be 135lbs-180lbs for a new belt and 80lbs-120lbs for an old one. Or, you can use the deflection method which involved using a straight edge on the belt and then pushing/pulling on the belt to measure how much it moves away from straight. The specs for that would be 1/4 inch on a foot of length.

My recommendation:
-Replace the Belt
-Buy a good quality belt, as even new belts will squeal if they're cheap.