A/C not working ??

you need to check the high side and low side pressures.

I added refrigerant today. The AC was very cold and was in the correct operating pressure at the low side port for the temperature it was today. The needle on the gauge sat at the high side of the 10psi range for the ambient temp for the day. When I pulled out onto the street and started to drive the AC air turned humid and warm like outside air. I know the pressure on the low side is good. To Meier's point, I was not able to check the high side pressure.

 

Does this help anyone further diagnose my issue?

 

I should say that the pressure is in range when the compressor is running and climbs into the red area of "overpressurized" a few seconds after the compressor shuts off.

Edited July 28, 2011 by TankTread

what is your pressure at a high idle?

I figured out my problem...

 

I bought a can of refrigerant with the gauge, checked the pressure and it did not register anything. So I followed the steps to charge it, filled it appropriately for the ambient temp. The compressor kicked on instantly, I took it around the block and then checked on it again, compressor was back off and very little pressure remaining. So I filled it back up, but this time with the engine off. I heard a hissing sound and after about 5 minutes tracing it around the engine compartment ... found a baseball sized dent in the condenser.

It's about as obvious as a bullseye, I recommend everyone check their condenser for holes before wasting money on a charge of refrigerant. At this point i'm looking for a new condenser and I will need to do the whole vacuum withdraw, fresh oil and fresh charge. I think its been at atmospheric pressure since last September.

 

Any advice on where to get a cheap condenser? Also I will be putting in mesh on the lower valence of the grill, that's where the rock came in.

Thanks guys for the assistance in helping fix my issue. I played around with the pressure on the low pressure side of the system and made sure to check the pressure and add refrigerant with the car already at operating temperature. I am not sure if this is a rule of thumb when doing AC stuff but when the car was at operating temperature the pressure was registering overpressurized at the low side port. I bled off some refrigerant until the needle was just inside the high range line at the ambient temperature of the day. Everything has worked without a hitch since. I hope I don't have to repost if we get a day over 95 degrees.

Rapid cycling is usually indicitive of LOW system pressure... not high.

 

with R134a systems there is a high pressure cutout switch. This will indeed cause the compressor to cycle on and off rapidly as pressure builds and then the switch trips off the compressor until the pressure drops and the compressor comes back on. Repeat. When R134a pressure is low, the compressor will not cycle at all.

yup

Several people condemning certain parts for leaks without testing for them first. I first replaced the O-Rings and receiver/drier to fix mine. It actually held a vacuum for an hour. After the recharge it worked fine for a week or 2. I thought I had it solved until it's effectiveness was waning. I ordered a UV light and found leaks at the front compressor seal and the corner of the condenser. The hoses are good. The compressor seal does emit small amounts of oil/dye normally but it has been sounding worse over the past few years. It makes a buzzing sound when the clutch is engaged. It works but sounds like it's on it's death bed. I'm replacing it with a new one. The receiver/drier must be replaced with a new one whenever the A/C system is opened up to the atmosphere. I can't diagnose the evaporator using a light. I will replace it anyway due to cost vs frustration of replacing the other stuff only to find out later it was leaking. You'll unlikely fix it by guessing. If you decide to replace a part, never get used A/C parts. New aren't that much. My entire order list, (hoses not needed), was $500. That's for a new compressor, condenser, receiver/drier, evaporator and expansion valve. Now watch me fuc4 it up when I install it next Sunday. Edited May 29, 2016 by stevenva

Hey guys I know it's an old thread but I have a 05 gt sedan, AT. I havent been able to figure out why my AC ne vcd er turns on. I fixed the compressor and had the wires test to behind the radio unit but theres no power going to it unless triggered by the tester at which time the compressor turns on and cool air starts coming through. my car also jumps idle like it would when the compressor gets turned on when I press the ac control on but nothing happens. Any ideas if I'm not too late