Mysterious A/C problem. (I read the sticky before posting) - Maintenance and Repair Forum

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Mysterious A/C problem. (I read the sticky before posting)
Saturday, July 28, 2012 1:33 PM
Please bear with me as I try to explain this.

The Compressor clutch engages, the system is fully charged, but it isn't able to maintain cold or even cool air with the fan speed turned up on a hot day in the sun (only blower speeds 3 and 4 are working) If you turn the knob to speed 1 or 2 and let the fan stop pushing air for about 5 seconds and then turn back to speed 3 you will get a cold burst of air that lasts only a few seconds. So I know that the car capable of making cold air.

This car has always had working A/C prior to this. I parked it for the winter/spring and it sat for about 6 months. Now I put it back on the road and the first thing I notice is the A/C is behaving oddly. Something else odd the clutch doesn't cycle on/off it just stays on. And when I put it on Max/recirculate the blower speed no longer increases and the air doesn't get cooler. Also, prior to this, with A/C on when I accelerated from a stop I could always feel/hear the compressor engage and bog the motor around 15MPH. That sounds weird, but that is how it has always been. Prior to now sitting parked this car always had mediocre A/C but once you started to accelerate it's as though the clutch went into full engagement around 15mph. It no longer does this and I think this is why the air is weak. Now the air is cooler sitting than it is moving. I swapped fuses and looked around under the hood but I'm not use to working on A/C systems so I'm not sure what to do next.

My three thoughts were the belt tensioner is getting weak and slipping slightly on the compressor, explaining why more rpms seems to weaken the air.

The compressor is not working properly.

There is something electrical causing this.

If this was my car I would just turn this into the winter beater instead of the summer beater. But I have my g/f driving 55 miles a day in it instead of her Wrangler which has no A/C. She can't look like a hot mess when she gets to work.




Re: Mysterious A/C problem. (I read the sticky before posting)
Saturday, July 28, 2012 3:06 PM
when your a/c is running are any of the a/c lines cold, sweating, or all hot? and how are you sure that the a/c is fully charged?
Re: Mysterious A/C problem. (I read the sticky before posting)
Sunday, July 29, 2012 8:59 AM
I hooked up a recharge can with a gauge and it showed charged, the system wouldn't take any freon. Right now I'm working on getting a set of gauges to check both high/low pressure at the same time. I'll check today and see what the lines are doing.



Re: Mysterious A/C problem. (I read the sticky before posting)
Sunday, July 29, 2012 10:42 AM
Yea, get a set of gauges... Thats the only way to diagnose, it could be a weak compressor or low charge...

Also I would get a garden hose and backflush the radiator and condensor really well to make sure your getting adequate heat transfer out of the condensor



Buildin' n' Boostin for 08' - Alex Richards
Re: Mysterious A/C problem. (I read the sticky before posting)
Sunday, July 29, 2012 11:21 AM
could also be the expansion valve.. if its plugged then your not getting any flow through the system
Re: Mysterious A/C problem. (I read the sticky before posting)
Sunday, July 29, 2012 11:30 AM
Jordan wrote:could also be the expansion valve.. if its plugged then your not getting any flow through the system


But this would cause the high pressure to build very fast, and cycle the clutch very often.
Re: Mysterious A/C problem. (I read the sticky before posting)
Sunday, July 29, 2012 11:43 AM
Dave De Stefano wrote:
Jordan wrote:could also be the expansion valve.. if its plugged then your not getting any flow through the system


But this would cause the high pressure to build very fast, and cycle the clutch very often.


True, shot in the dark I guess. Its hard to tell anything without knowing the pressures... just throwin out options
Re: Mysterious A/C problem. (I read the sticky before posting)
Sunday, July 29, 2012 3:18 PM
Jordan wrote:
Dave De Stefano wrote:
Jordan wrote:could also be the expansion valve.. if its plugged then your not getting any flow through the system


But this would cause the high pressure to build very fast, and cycle the clutch very often.


True, shot in the dark I guess. Its hard to tell anything without knowing the pressures... just throwin out options


I agree. It would be very helpful to know pressures
Re: Mysterious A/C problem. (I read the sticky before posting)
Monday, July 30, 2012 3:07 PM
Pressures at idle 29 low 150 high, according to the gauge set that is just in the acceptable range. The lines that wrapped in heat shield are hot and one small line running up towards the accumulator (not the large one going into it) is ice cold. The Accumulator itself feels ambient and there ins no condensation on it after running for 20 or so minutes. Something strange I noticed while leaning in and out of the car, the a/c vent to the left of the steering wheel is putting out colder air than all the other upper and lower vents. I'm starting to think this may be some type of HVAC system issue since I'm already having a problem with Recirculate not behaving as it should.

Is there a spot that I can grab something with my hand to manually adjust cold or hot air coming in?



Re: Mysterious A/C problem. (I read the sticky before posting)
Monday, July 30, 2012 6:02 PM
I found the hard line to adjust the climate control and it was on full cold. I went and picked up a .12oz can of 134 and put it in. It brought my low pressure up to 41, my high pressure was reading around 140 and was at 150 when the can was empty. My lines to the accumulator are cold and condensating now. The air was much cooler. However, I still have not figured out why recirculate doesn't increase fan speed and lower A/C temp like it should. Lastly, the compressor doesn't engage and load on the engine like it use to when accelerating above about 15mph. I know these compressors are variable speed, I wonder if it is malfunctioning and not working to it's maximum ability.



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