2005 Chevy Cavalier AC out.
acquestions Member Posts: 4
edited March 2015 in Chevrolet
I have a 2005 chevy cavalier and the ac went out recently clutch is engaging, fans are working, and the freon is at the percentage for my areas temp. Low pressure line going to dryer is barely cool and the dryer and other lines are even warmer, any idea, I believe it may be the high pressure switch or some kind of blockages
The sensible heat (what we measure as temperature or feel) is an important part of the diagnostics. The refrigerant entering the condenser should be some twenty to fifty degree's higher than what is leaving the condenser. The refrigerant leaving the condenser should be twenty to thirty degrees higher than the ambient temperature. The refrigerant temperature leaving the evaporator should be +/- five degrees what it is right after the orifice tube if you can reach it to measure it. There should be no more than one degree temperature change as the refrigerant passes through the accumulator.
These measurements should be taken with the engine running about 1500 rpm, cooling fans on (fan in front of the condenser) The doors of the car open, MAX AC setting, full cold, high blower speed.
Now based on the image with what you wrote, the temperatures that you are suggesting have the evaporator outlet more than five degrees warmer than the inlet, and the condenser inlet not hot to touch. That means you are not picking up heat in the evaporator (low side) and moving it to the condenser. Liquid refrigerant should still be boiling and absorbing heat all the way to the accumulator which is why it should be much colder than what you described. By it not being cold that means you ran out of liquid refrigerant and started adding super heat to the refrigerant which results in a temperature change of the refrigerant. Then when the compressor compresses the refrigerant, the fact that you didn't pick up much heat in the low side is reflected by not having a big increase in sensible heat on the high side.
This is easily undercharged, the compressor isn't pumping correctly, the refrigerant contaminated, or all of the details haven't been provided and a first hand inspection of the system would reveal something that hasn't been mentioned.
Today we start with a scan tool and look at the system pressures (temperatures) and the system inputs and commands before we do anything with the AC machine or gages. Now the fact that you mentioned the compressor clutch was not staying engaged, that is an important detail. You need to use a scan tool to see if it is being commanded off and if so what input is making the PCM do that.