a/c vent temperature fluctuation

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Jun 26, 2003 | 04:35 PM

cheesedog1

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Joined: Sep 2002

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a/c vent temperature fluctuation

Hi:

I hope i am in the right place. I just bought a 94 aerostar 3.0L w/ dual a/c. It has r134 in it. I put a temp gauge in the vent & it fluctuates between 45 & 65 degrees. The compressor runs constantly & does not shut off. Is this normal? I had another 94 aerostar & I don't remember it doing this. I don't know the history of this vehicle but it only has 60K on the odo & everything looks good under the hood. Any help would be greatly appreciated.

Thanks in advance

Jun 26, 2003 | 05:41 PM

aerocolorado

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Joined: Apr 2001

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a/c vent temperature fluctuation

Your system could be overcharged. The compressor should cycle on/off 2 or 3 times a minute normally. There is a fine line between over and underchaged states. A bad fan clutch will also cause poor overall A/C performance. You need to get someone to put some gauges on the system to see what the readings are and go from there.

Jun 30, 2003 | 07:08 PM

LxMan1

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From: Louisville,Ky.

a/c vent temperature fluctuation

It could also have moisture in the system causing the evaporator to freeze up.

Jul 2, 2003 | 11:04 PM

greg_23805

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Joined: Sep 2002

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a/c vent temperature fluctuation

Are you sure your a/c clutch isn't cutting on and off. The temp fluctuation you have is typical of the compressor cutting on and off. Moisture inside the system won't cause it to freeze up.

Run your engine in Park up to about 1500 rpm and have someone watch the compressor or you watch it to see if it cuts on and off.

IF the compressor is running all the time, then it's low on freon. The compressor will cut on and off if you run max a/c and the temp inside gets cool enough.