Insp58255

Wifes 2002 AVALANCHE had Ice cold air up until transmission went out and was replaced. Now the air is cold enough. Changed high and low switches had plug on back of compressor changed. Have new control panel. And unit is charged. Please any help will be greatly appreciated.

oilcanhenry

Whats the high and low charge PSI at now? Are the inlet and outlet A/C lines cold at all? Did the shop mess with the A/C condenser or the transmission cooler?

Insp58255

I checked the lines. The one with the LP

and HP caps is not cold the thick one on top is warm. Also when I hold the lines I can kinda feel it pulsing.

kevinkpk

If it is "pulsing", either that high or low pressure cutoff switch is bad, or a low charge/leak.

Fred R

If the compressor is clicking on and off, it could be related to the switches. If you feel the refrigerant lines pulsing, it’s very likely a charge issue. You can get the cans of r134a at the auto store with a little gauge and charging instructions for $30. If you foresee doing this in the future or just want to know more about refrigerant charging, you can get a cheap set of gauges and auto adapters at harbor freight. I think they may even sell the small cans of 134a that have a puncture top (you’d also need a puncture valve) second option costs three times as much, but will pay for itself if you have to do this a lot.

Insp58255

I pulled the plug off the low pressure switch and compressor goes off and back on when I plug it back in. The compressor is very hot and there looks like oil on the bottom. Could it be the compressor itself?
Now the air is blowing Hot. I do t have gauges so I checked the low pressure side with the gauge on the can it was full on the green.

Fred R

if it’s refrigerant oil it’s not a good sign. Assuming you have a shiny clean engine and that’s the only place you see oil... you likely have a leak right there. Refrigerant systems are sealed and should not leak out oil, ever. Refrigerant leaks can be easy to trace. I’m not familiar with what kind of fittings are on your vehicle, but possible they can be tightened or an o ring replaced. If the compressor is running you have enough pressure to spray some soap bubbles (gas leak detector). Careful... it’s propylene glycol and smokes like crazy if you let it drip anywhere hot. You could also do a soap bubble test with the motor off.

oilcanhenry

I'm a bit confused as to the two inlet/outlet connectors on this vehicle. The larger red one _Should_ be for High Pressure and the Black one for low pressure, but they appear to be on the _SAME_ HP line going into the cabin evaporator. Perhaps my old eyes are deceiving me, but this seems very strange and/or peculiar to me, and I've done lots of auto A/C systems in my lifetime. The larger, low-pressure tube does not seem to have it's own refrigerant pressure gauge outlet at all. A very, very odd design to me, for sure.

On the plus side, having an aluminum wrap foil on the R/D/C unit seems like a good idea. I have some left-over wrap for my home water heater that I could put on my Chevy K-1500. I agree that PAG oil on the compressor is a very bad sign that it is indeed leaking R-134A refrigerant and PAG oil. Likely going to need a rebuilt or a new compressor in order to function properly, once more.

oilcanhenry

Can you post a picture of the PAG oil leak and the A/C compressor? Also any other outlets from the larger low-pressure outlet tubes/hoses going to the condenser?