I have installed the ac system back on my 1971 gs and am having a problem with cooling. I insalled a new compressor,dryer,and expansion valve and 134a. I am not getting any cooling in the evaporator but the suction line is frosting up where the small line from the evaporator (oil bleed port) enters the poa valve to the compressor. I have 80 lbs pressure at valve port on poa valve. Is this a poa valve problem or restriction some where else? Mike
100 lb on high side with compressor running, but I could only get 1 lb of freon in system. I charged system on low side at poa valve port compressor running (gas not liquid). It seems that all I can get in system is from charging port back into evaporator. Evaporator seems to be open when I blew compressed air in it.
Yep. Sounds like the POA is stuck closed. The service port measures pressure between the evaporator and the valve, the suction hose is likely in a vacuum. The oil bleed line is acting like an orifice. Here's an article on testing the POA valve: http://www.autoacforum.com/messageview.cfm?catid=20&threadid=16311
Your POA valve must be recalibrated/flow tested for R134....will not work if you just changed over and did not reset the valve....will never blow cold at low rpm.
