2004 Ford Crown Victoria A/C cycling problem

  • 4.6L
  • RWD
  • 124 MILES
My car does leak freeon. But it takes a good month or more to leak to where the compressor cycles very rapidly no matter if I'm driving or idling. But if I fill it to where it's full.. It stay engaged while idling(34 degrees coming out of the vents) but as soon as I start driving it cycles on and off every 5-7 seconds. Even if the cab of the car is still hot it cycles on and off alot when I'm driving. It'll get down to 38 degrees but it takes a lot longer with the compressor cycling than it would with it staying engaged. Could it be a bad high pressure switch or what. Any help is appreciated
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Friday, October 3rd, 2014 AT 8:45 PM

1 Reply

Other than the obvious major leak, you're looking for a problem that isn't there. The compressor cycles based on system pressure on the low side, and pressure is based on temperature of the evaporator. If you're measuring air temperature from the vent outlets, 38 degrees is definitely not good and the compressor should be cycling off to help regulate the temperature higher.

The goal of all air conditioning systems is to drop air temperature by up to 20 degrees, and no more. There's no point in making it so cold you have to wear a sweater to be comfortable. The real comfort comes from removing the humidity from the air. Most systems can get down to 40 to 44 degrees if given enough time, but even then you have to worry about evaporator freeze-up. To get 60 degree air, you have to take 80 degree air and pass it through something considerably colder than 60 degrees. Once the evaporator is allowed to hit 32 degrees, the condensed humidity will freeze instead of draining off to outside the car. That ice builds up very quickly until it completely blocks air flow. If you're getting 38 degree air, the evaporator is likely in the low 20s. Either you have something bypassed or the orifice tube is stuck open.
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Friday, October 3rd, 2014 AT 9:15 PM

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