My AC blew relatively cool not cold but cool and all of a sudden it started blowing barely cool. Like just a hint of cool air. I looked under the hood and noticed what I've learned is the POA valve and the hose to the compressor white frosted. It keeps happening now every time I use the AC.
I have 71 Cutlass. New/ remanufactured compressor, new dryer, new expansion valve. It uses R-134. I believe the POA valve setup is for R-12. I know nothing about the pressure on it anywhere.
I saw posts on here discussing this issue but missed the fix. Do I get one of the newer valves that says it's more efficient system? Or is there dirt in my system, or do I have a leak? I don't know. These seem to be the options. So what do you think?


This same frosted hose connects to the compressor

 

Did you vacuum the system before replacing the new parts.If not, there's probably moisture in the system and once it reaches the expansion valve it freezes . If you didn't pull a vacuum on it you will have to,and recharge it. I am not sure about the difference in the POA valve ,but 1 drop moisture will cause the freeze up that is happening. Good luck, Larry

 

Thanks Larry. Yes we put a vacuum on it initially.This system was put together last summer and has been working. Not the coldest air but cool. Now it's somewhat, kind of cool.

 

It could be that that old hose has collapsed inside , and is acting like an expansion valve.
A new set of hoses couldn't hurt.

 

My car was doing that. It ended up being the POA valve. Initially I bought one of those "POA update kits" which make the a/c compressor cycle. I didn't care for that set up and sent my original POA valve to Classic Auto Air. They tested it and verified that it was bad, rebuilt it and calibrated it for R-134. That was about 2 years ago.

 

did you see this thread? https://classicoldsmobile.com/forums...2-cutlass.html

 

That's not an adjustment problem, looks like an internal failure. Maybe the adjuster screw worked itself loose and got dramatically out of position? That's quite unlikely though. POA has a vacuum reference, and as with anything this old, that kind of stuff can break.

What's happening is the outlet side of the POA is now the primary restriction instead of the expansion valve. It'd be interesting to see what the system pressures are. Be careful, as the system could easily be out-of-wack enough to cause the compressor to fail. A6's are pretty robust thanks to their oil sump, but extended running without refrigerant flow will still kill them.

There are a couple of eBay sellers that recondition POAs and keep some in stock. Just have to correctly identify which port configuration you have. Then it's also your option to recalibrate it (or have them do it) for 134a.

 

I can test/rebuild/recalibrate them if you are interested.

 

I had the same issue. The POA is frosted but not all the way, meaning it is blocked. It is not letting the refrigerant get through and into the evaporator. I had Classic Auto Air rebuild and recalibrate mine for 134a, and with a parallel condenser, it pumps out 30-35 degree air at the vents.