2000 Regal. AC works fine, then after about 10 minutes it turns off. Then after another 10 minutes it turns back on. Rinse. Repeat. What should I check? I want AC on all the time.
AC turns off and on every 10 minutes!
Posted 12 July 2018 - 03:04 AM
Posted 12 July 2018 - 03:21 AM
The pressure is there. There might be air but the pressure is there for sure. If anything, there is too much refrigerant.
Edited by jason.arthur.taylor, 12 July 2018 - 03:21 AM.
Posted 12 July 2018 - 12:40 PM
You'll probably have to pull a vacuum and make sure the right amount of refrigerant is in the system. That will help diagnose where the problem is. Could be compressor clutch or pressure sensor too.
Posted 12 July 2018 - 01:17 PM
Thanks for the advice.
My thoughts on the clutch theory: I don't think it is the clutch. If it were, I think it would have other symptoms, like never turning on in the first place, right? Turning on and off in a timed fashion suggests to me that some gas needs to change temperatures or pressure before the pcm switches the system back on.
My thoughts on a pressure regulator being bad: Not possible. Are you saying the pressure is too low and it is turning off, or the pressure is too high and it is turning off? My experience is that it only fails to turn on if the pressure is low. That's all the pressure switch does. One the compressor kicks in a first time, the pressure on the high side will be high enough to prevent that switch from going into the low state. Am I wrong?
My thoughts on the idea of pulling a vacuum for 1/2 hour:
If I recall correctly, I already did for 1/2 hour. I'm not sure I want to pull a vacuum for kicks unless there's a logical method by which the pcm is able to shut down a system with air or moisture in it. Is there? Does anyone know? What are the symptoms of a system with air or moisture? I mean this should be a known reason one has to pull a vacuum. I mean that's why I'm posting here in the hopes of getting someone who says, yeah, you need to do this for this problem. Otherwise I'd be doing all sorts of stuff like putting more oil in the system, changing the desiccant filter, checking for leaks, swapping parts that aren't bad, etc.
Edited by jason.arthur.taylor, 12 July 2018 - 01:32 PM.
Posted 12 July 2018 - 01:47 PM
Pulling a vacuum will let you know how much refrigerant is (was) in the system. It also gives you an opportunity to check for leaks. It also allow you to replace the correct amount of refrigerant, oil, and potentially UV dye for future leak detection.
Posted 12 July 2018 - 10:56 PM
Pulling a vacuum will let you know how much refrigerant is (was) in the system.
Posted 19 July 2018 - 12:00 PM
I don't have a $1000 recovery machine.
I solved the problem. A key symptom was how the numbers change with the weather: in hotter temperature, the duty cycle of the system was on less. In colder temps, the ac was on more during the cycle. Clearly, all pressures are higher at high T, so this suggests that a pressure-related cutoff was happening at high P. Indeed, once the pressures were lowered, the system worked correctly. The system has 150 psi high and like 50 low now and works great. I did not evacuate or anything. The PCM protects the system by monitoring the high-side pressure. The cutoff for this car is probably around 400 psi. I don't actually know how high it was because while hooking up the gauges I lost a lot of pressure. Anyone with intermittent ac should read this post.
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