We just purchased '06 PT Cruiser 4 cyl w/23K miles on it. We have been following the operation manual instructions, but the a/c stops cooling and the fan force seems greatly decreased about 45 minutes into a trip. If the car is off for 30 min or so after one of these incidents, then we start the engine again, visible vapor, even snow-like substance blows out upon restart. Any ideas?
It sounds like the evaporator coil is freezing up. That can happen due to a refrigerant leak or reduced air flow. Is the suction line excessively cold or frosted over when it stops working?
Do not operate the A/C until it’s fixed as liquid refrigerant returning to the compressor can damage it.
Is it still under warranty?
The A/C is supposed to cycle off when the evaporator coil gets too cold, then turn back on once the coil warms up a bit. This on, and off cycling is perfectly normal for a auto A/C. I suspect that the evaporator temperature sensor is malfunctioning causing the A/C to not cycle off when the coil gets too cold causing the coil to freeze. If the car is still under warranty take it back to the dealer.
In A/C, the evaporator coil should never get cold enough to trip the freeze protector on the coil, if there even is one installed. Defrost cycles are for refrigeration systems and heat pumps operating in heating mode. A/C systems do not have defrost cycles.
The fix is to fix the problem that’s causing the evaporator coil to freeze in the first place.
Thanks for your input; I wonder why prior owners didn’t get it fixed? Anyway, you’ve helped me to identify that the problem is not the “nut behind the wheel,” but is truly a malfunction of the equipment. We still have warranty time, so we’ll get it in on Monday. Thanks especially for the warning about not using until it is repaired. Want a smile? The owners traded the Cruiser in on a Hummer!!!
Star, it is completely normal for a auto A/C compressor to cycle on and off, on either low pressure or low evaporator temperature to prevent coil freeze up.