Air conditioner problems

I have a 1995 Toyota Avalon. I have been having an issue with my air conditioner. I have had it ‘repaired’, but it still gives me trouble. What happens is that when it is very hot out and usually when the car has been running awhile, the air stops working. It will not start working again until the engine has cooled down. Does anyone have any ideas how to fix this?

This condition is called “freeze up”. Your AC evaporator will freeze when used in very hot weather and that will cause the AC to stop functioning until it defrosts. Some cars and trucks are more prone to this than others. Try setting the temperature a little warmer instead of the coldest setting and the condition may improve. Humid weather makes this condition worse.

If the car was dispacthed to me I would pull the charge out and evacuate for an extended period(3+hours) and then charge by weight (some are better with the pipe temperature method), I go by weight.

Good advice oldschool. I forgot that this condition is also cause by overcharged refrigerant.

Thank you. I have turned off the AC and let it ‘cool’ down, it usually takes a full night of cooling down to restart the AC.

I have had the car in for this problem. They have recharged it and they say nothing is wrong, because by the time they work on it, it working again.

If this car uses a “clutch cycling switch” to control the a/c, it could be failing/sticking. This device is a pressure sensor that detects when the pressure in the system drops beyond a certain point (it may also detect if the pressure is too high), then it cuts out the compressor, turning it back on when the pressure returns to the preset range. By this means, the running of the system is regulated to prevent evaporator freeze-up and also to prevent damage to the system. If any kind of additive like a leak sealer or similar has ever been added to the system, the chances of this getting gummed up are increased.

If the switch is gummed up and sticking, or faulty, it may not click back on until the car sits for a very long time. The one on my vehicle was doing exactly this, and it was driving me crazy for a while. This sensor is not repairable, and must be replaced. On mine (Chrysler), fortunately it was attached in one of the condenser lines, fairly easily accessible, and connected to a Schrader fitting (like the valve on your tire) so that it was easily replaceable without losing charge from the system.

An easy test would be to jumper the wires on the sensor the next time your a/c won’t start. But don’t totally defeat this—the system needs it for normal operation. The replacement part for mine was around $80. No idea how much it would be for yours, or even if yours uses a similar part.