AC pulley/serpentine belt

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- Usenet user
  
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posted
18 years ago

Sat, May 14, 2005 2:21 AM

Has anyone had any problems with their air conditioner pulleys and the serpentine belt?

I just found a problem with my 99 Explorer, and came rushing to this group for help.

Basically, today I noticed a strong clicking coming from under the hood. I had turned on my car and was still parked with the AC on. I popped the hood and found that the pulley connected to the AC was alternating regularly between spinning and not spinning. If I turned off the AC, the pulley stopped spinning completely, of course with the belt still going over it.

To tell you the truth, I don't know much about cars, much less the specifics of AC units, and I don't remember what exactly that pulley was doing before, but this just doesn't seem right. The serpentine belt going over a locked pulley just can't be good for the belt, can it?

I'm about to go on a ~9 hour drive through the desert too, so I'm going to want to take this to get fixed ASAP, but any info you could give me would be awesome. It would be great not to seem like a moron when I go up to a mechanic.

The reason I ask about Explorers in general is because I seem to recall my parent's had a very similar problem a couple of years ago.

Thanks

- C
- Charlie Bress
  
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posted
18 years ago

Sat, May 14, 2005 12:57 PM

Are you getting cold air? I wonder if you don't have it backwards. The a/c pulley is probably stopping when the a/c is on.and spinning when the a/c is off.

This problem happened to my 92 years ago. The pulley stops spinning because the a/c compressor has failed and is locked up.

Running in this condition will shortly destroy the belt. You must get this fixed as soon as possible. Until you get the problem taken care of, do not operate the vehicle with the a/c on. As a precaution, if you look at the a/c pulley area, you will see a connector with a pair of wires leading up there. Unplug this connector. This will let you drive to get the system repaired. If the belt breaks, you will lose power braking, power steering, and engine cooling as well as the alternator that supplies the power to operate the electrical system. .

Trying to drive across the desert in the condition the SUV is in now is extremely dangerous.

Charlie

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- Mikepier
  
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posted
18 years ago

Sat, May 14, 2005 4:40 PM

It is normal for the compressor to cycle on and off . But if it cycles like every 5 seconds ,then you have a problem.

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- Happy Traveler
  
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posted
18 years ago

Sun, May 15, 2005 9:30 PM

The compressor has an electrical clutch. When engaged, the hub is turning along with the pulley. When disengaged, the pulley just idles and the hub stops. Ford A/C systems cycle the clutch to maintain the correct pressure and prevent the evaporator from freezing. The frequency depends on ambient temperature. If it cycles very rapidly (every couple seconds or so), you have a low charge situation or some other malfunction. If it's slower than that and the A/C is blowing cold air, everything is probably normal.

If I misunderstood you, and the pulley stops, with the belt rubbing around it when the clutch engages, you have a seized compressor and will soon destroy the belt, possibly along with a few other components. There would obviously be no cooling in such condition.