Alt. Belt slips when RPMs below 1,000, cont.

[Festiva Time]

Car: '90 Festiva l-plus, 5-sp. Previous failure: alternator, lead to dead battery.
When I start the engine (Foot on the Brake) the alternator belts squeals alittle at idle [900rpm] until about a minute, the idle smooths out & squealing is gone. If I step on the brake pedal, my RPMs drop 200 and the belt start squealing, again. Squealing will get worse the higher the RPMs [Stinks too!].
I have a new Alternator and Belt. I tried Belt dressing spray. I feel I have the Belt tension too tight , I can barely get any deflection. In the Haynes manual, it says I should have: one volt on the "L" terminal with the ignition on. I get almost 4 volts. Is this ok? It does not say. All other tests are ok. I do not know if I am getting 35amps out of it, If I need it. Voltages ok. I checked my Water Pump, it spins easily. The belt dust is on the Alternator body, so it must be slipping there. Battery staying charged up. Thanks for any suggestions you can give.

[crazyrog17]

you're supposed to have some deflection in the belt. my girlfriend's 323 requires 8-9mm of deflection for a worn in belt, but 6-7 for a new (it'll break in).

loosen up the bolt in the slot on the mount and adjust the alternator's angle until you get the proper deflection.

[batstiva]

Per my Hayne's deflection with a new belt should be 8 to 9 mm. Deflection with a used belt (defined as a belt that has been used for five minutes or more) should be 9 to 10 mm. Exerting about 22 pounds of pressure on the belt midway between pulleys.

Don't know if you have any kind of oil leakage on your car, but I just did the belts on both of my cars, because they both squealed at start up. I found that my deflection was correct, but I had oil on the pulleys on both cars. Removed the old belts, cleaned the pulleys, installed new belts properly tensioned, and now no squealing. In general, I distrust spraying anything on the belt, as it seems to me that lubrication equals slippage. Just my opinion tho.

[Mike McKown]

Don't know if you have any kind of oil leakage on your car, but I just did the belts on both of my cars, because they both squealed at start up. I found that my deflection was correct, but I had oil on the pulleys on both cars. Removed the old belts, cleaned the pulleys, installed new belts properly tensioned, and now no squealing. In general, I distrust spraying anything on the belt, as it seems to me that lubrication equals slippage. Just my opinion tho.

I'd be looking at the above as a cause of the belt squealing. The alternator belt doesn't have to be as tight as the book says if everything is working properly.

I've sprayed Brake Clean on belts and stopped squealing.

Assuming you have the correct belt, right width/pitch, and the pullies are aligned and clean, the only other thing I can think of is a high load on the alternator. If that's the case, change batteries and see if your problem goes away. Yeah, I saw where you said the battery is staying charged.

[Festiva Time]

Thanks for all your suggestions. I am going to replace the belt [save this one for emergency] and adjust the belt with more deflection. This belt I had to adjust really tight because it squealed badly all the time. A "Ford" mechanic said to get the belt tighter. I told him, I got it tighter than the old one and I was afraid if I went tighter, I would be overloading the water pump bearings. He said it was ok, to go tighter. I did it, and the squealing disappeared. Retightened after about 300 miles. No problems until now. Next, I will see if I can get hold of another battery and try that. Many Thanks! Kirk

[ejp2fast]

my belt squeals sometimes in the mornings when its humid and i come up on a stop sign and idle.. . then when i go to go, it squeals for about 3 seconds....

[batstiva]

my belt squeals sometimes in the mornings when its humid and i come up on a stop sign and idle.. . then when i go to go, it squeals for about 3 seconds....

That's pretty much exactly what both of mine were doing before I removed them, cleaned off the pulleys, and installed new ones. My old ones were tensioned correctly, but I am assuming in my case, oil on the pulleys was allowing the belts to slip.

[LoneManWolf]

That's pretty much exactly what both of mine were doing before I removed them, cleaned off the pulleys, and installed new ones. My old ones were tensioned correctly, but I am assuming in my case, oil on the pulleys was allowing the belts to slip.

mine did this also a while back when my valve cover was leaking replaced gasket cleaned all pulleys and put on new belts doesn't squeal anymore

[ejp2fast]

sweet guys, i'll remove the belt, clean pulleys and belt really good and reinstall, that should do the trick.. now i have an excuse to work on it again!

[1988redfordfestiva]

mine was doing this belt was warn but i have a new alt had to replace and tight snugg

[scitzz]

Dayco belts do this to me all the time. I can't buy them from advance auto because of this. Make sure you are buying good rubber