A/C Compressor quits intermitently when stopped or driving slowly. (1 Viewer)

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Joined
Aug 17, 2010
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2
Messages
7
Location
Orange, TX
At normal driving speeds my A/C puts out a constant 40 degrees on very hot days.
If I stop at a traffic light or slow down the compressor usually goes off and
doesn't start back up until it is driven at highway speed again for a while.
Does anyone know the cause and fix for this? Thanks in advance.
 
Normal on the gauge or normal actually measured?

cheers,
george.
 
Gauge is somewhat/mostly useless. It is very conservative and a poor indicator of actual engine temperature.

What year is your 80. OBD2? If so, then get a reader and see what engine temp is being reported.

The 80 will turn off the AC if the ECU determines the engine is too hot. From your original post it is more than likely a too hot condition.

Causes for that are typical cooling system issues, like last time it was service, condition of the radiator and most importantly the fan clutch. If original stuff, then more than l#1 issue is more than likely the fan clutch. Lots of posts on that issue on this forum. Start searching :) The fan should 'roar' when the vehicle is first started from cold after sitting.

cheers,
george.
 
If you set the AC to max cold with recycle "on" and the doors open, does it cycle on and off?
 
The A/C shuts off at ~227 F as a last ditch effort to save the engine, but the dash temperature gauge will read normal at 227. An OBDII reader will tell you the actual temperature. Most likely, your fan clutch is not up to the task of keeping things cool while you're not moving fast. Or your coolant is super duper old. Or your radiator has seen better days.
 
Agree with all of the above. Very likely high temperature cut out....BUT not necessarily due to the engine actually being too hot.

The sensor itself could be bad (causing a false hot cut off).

So..the OP has several things to look into.

temp sensors1.jpg
 
Last edited:
Or he could be low on refrigerant...
 
The system will also cut out based on the refrigerant pressure being high or low. So even with the engine operating with normal coolant temps if the condenser is plugged or not getting enough air flow the compressor will shut down. So I’d start with the fan clutch if the ac has refrigerant.
 

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