Uncommon AC Question

[TheGuyWho]

My AC runs, but its not ice cold like in my Lightning. Its not hot air, its just cool air. Its 107* out here, and its my wife's car, so of course ive been hearing about it for the last week or so! LOL
So this problem has actually been an ongoing battle for me. Ive been trying to trouble shoot it, but no dice. Ive checked the vacuum lines, and they're fine, so no vacuum leak. I changed out the condenser for a brand new unit. New free-on @ approx. 35-40 psi. And I also replaced the blend door and blend door actuator. I can hear the compressor working, and turning over, but possibly too quickly or too often? Meaning it cycles on and off within 15-20 seconds, which seems to frequent to me. I really don't think the compressor itself is bad, but Im not positive. I just noticed yesterday that the hoses that come from the condenser are not cold. In fact they are hot! This is not how they are supposed to be. If I remember from my Lightning and Mustangs, those lines should be ice cold and even dripping with cold condensation, right?
Does anyone have any ideas as to what could be wrong, or why the lines aren't cold? Is there a blockage? Is my compressor not functioning properly, what? I just really don't want to have to take it to an AC shop and get ***** on the prices because its summer and they know people want AC. I can do the work myself if I could just figure out what is wrong. And an almost $300 new AC compressor is a large "guess" repair.
Thanks for the help brothers!

 

[stamp11127]

Anytime you troubleshoot a/c systems you should start with the static pressure after the system hasn't run for a few hours. Next is the low and high side pressures with the system running at idle. And of course they are dependent on the outside temps so you need to know that also.

The compressor cycling is from low pressure or high pressure, the most common being low pressure. The system has switches that protect from both conditions. Gauges will tell you which one is your problem.

You can get a decent set of gauges for around $120.00 or cheaper sets at HF for around $60.

When you changed the condenser how much vacuum did you pull and for how long?

 

[bojaz01]

Theguywho....i agree with stamp.....the suction line is the line that should be cold/have condensation on it, the liquid line/high pressure line would be the one that is hot....a refrigerant over charge would cause the compressor to cycle on and off repeatedley, it would still blow cool air just not cold....I had a residential system do that, i recovered refrigerant until the pressures balanced out and the temp/pressure coincided. of course you will need gauges to confirm......oh, does the 35-40 psi match up with the ambient temperature stated on the press/temp chart for r134?

 

[robbieg]

When you replaced the condenser did you draw down a vacuum before you charged it?

 

[jdan]

Usually on a mild day like 80* low humidity low side is around 40 psi and high side is 150 psi going from experience. with your environment the numbers should be higher and as stated above did you do a system vacuum? If not that could be an issue since you will have air in the system. Then you gotta recover the freon and start over again.