1991 Corolla Odd A/C Problem

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1991 Corolla Odd A/C Problem

Postby poopeater » Mon Aug 28, 2006 8:57 pm

Hello everyone,

I am having an issue with the A/C in this car. So you know how when you are running your A/C, the system will turn the compressor on and off as needed to keep blowing cool air? Well, when I turn the system on, it will run fine for a couple of minutes until the system cycles the compressor off. When it cycles it off, I get a HORRIBLE squealing sound out of the engine bay. I've looked in there, and it looks like the compressor is seized. The squealing is the belt driving over the un-moving compressor pulley.

The odd thing is that when the A/C is fully turned on with the magnetic clutch engaged, the compressor pulley spins fine. Also, if I manually turn the A/C off, the clutch pops out just as it should, and the pulley still spins freely. The problem only occurs when the system cycles the compressor off. Why would this be happening? Any ideas?

Thanks,
-Ben
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Postby Cusser » Tue Aug 29, 2006 3:56 am

Poop - the first thing I'd try would be to replace the AC belt with a brand-new high quality Gates brand AC belt. Yours might just be glazed, so try a new belt like Gates (Carquest) and tighten it correctly. It takes a lot of oomph to turn a compessor, and a glazed belt could simply not have enough grab, even if tightened further.
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Postby Hylander_1314 » Tue Aug 29, 2006 5:36 am

Also get a manual for your car, and make sure to keep the belt tensiond properly. Yours should be a manually adjusted belt, not an automatic spring load type.
What a way to fly into a war, unarmed and outta' gas..............................
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Postby poopeater » Tue Aug 29, 2006 3:50 pm

Thanks for the ideas, guys.

However, wouldn't it be more difficult to spin the pulley once the clutch is engaged and the compressor is actually being spun? My belt will turn the compressor just fine. The issue only crops up when the system cycles the compressor OFF. In this case, the compressor pulley should just be free-spinning...there would be no compressor load on it at all, yet this is the case where I am seeing a problem.
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Postby poopeater » Tue Aug 29, 2006 4:52 pm

Cusser wrote:Poop - the first thing I'd try would be to replace the AC belt with a brand-new high quality Gates brand AC belt. Yours might just be glazed, so try a new belt like Gates (Carquest) and tighten it correctly. It takes a lot of oomph to turn a compessor, and a glazed belt could simply not have enough grab, even if tightened further.


Are you referring to the serpentine belt?
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Postby Cusser » Tue Aug 29, 2006 6:46 pm

From your added info, it sounds to me that the noise/squeal occurs once the current to the AC clutch is disconnected. So that sounds like a bad clutch bearing....should spin freely....turn off engine, take off belt, spin by hand. Do this while engine is hot, and also do when engine cools off....should spin freely when AC not in use, and clutch coil should lock it up when AC compressor gets voltage.
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Postby poopeater » Tue Aug 29, 2006 9:07 pm

Cusser wrote:From your added info, it sounds to me that the noise/squeal occurs once the current to the AC clutch is disconnected. So that sounds like a bad clutch bearing....should spin freely....turn off engine, take off belt, spin by hand. Do this while engine is hot, and also do when engine cools off....should spin freely when AC not in use, and clutch coil should lock it up when AC compressor gets voltage.


Correct...this is why I am confused:

1. If I manually turn the A/C off, the compressor pulley spins freely with no issue at all.

2. If I have the A/C turned on and the system cycles the compressor off, the compressor pulley locks up and does not spin. I can physically see that the clutch disengages, so there should be no reason why it won't spin.

I would think that in both of these cases, the pulley should spin freely. Why would that pulley only lock when the system turns the A/C compressor off? Would that be related to the clutch bearing?
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Postby poopeater » Tue Aug 29, 2006 9:11 pm

Just to summarize:

1. System turned off manually - compressor pulley spins fine, clutch correctly disengaged, no issue

2. System turned on with compressor activated - compressor pulley spins fine, system blows cold air, clutch correctly engaged, no issue

3. System turned on with compressor cycled OFF - compressor pulley locks up, clutch appears to be correctly disengaged. Why the locked pulley here?
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Postby Hal » Tue Aug 29, 2006 11:56 pm

Your compressor is locking up. What you think is the clutch cycling off is actually the compressor seizing. Was the system ever worked on, refrigerant added? If so, was anything other than refrigerant added to the system? Expansion valve systems seldom cycle, so what you are seeing "appears" to be the compressor cyling off, where it's actually seizing and trying to turn, but only the pulley will. Take the belt off and try turning the pulley and the outer hub. Both should turn smoothly and the outer hub should not have rough spots or binding. If the system was charged by a kit, that is most likely your problem
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