I have a 1970 olds. 442 orig. ac system with r12 .
the system is blowing air but not cold
the system is fully charged r12
i notice frost half way along the POA valve .
lower the expansion valve is not cold ??
the heat works fine .
is the POA valve clogged or the expansion valve bad ?? or what do i need to test .
compressor is running clutch is engaged

 

Autotopia recently featured a '66 442 restomod - still has a 400 Olds. It was an original AC car but missing the components when he got it. He went Classic Air. I have a '69 GTO with the original AC system and its charged with R134. It doesn't blow very cold. I've heard its a matter of a properly adjusted POA valve. I have cans and cans and even a tank of R12 but no one will put it in for me. The valves on the car for the introduction of freon are different between R12 and R134. Right now I'm working on a '66 442 myself and awhile back aquired most everything to resurrect the original system but now after watching the Autotopia episode I wonder if its worth it. A system designed since new for R134 will cool properly. I've also heard the original system wasn't so great even on R12.

 

It's been a while since I lived in an area with enough humidity to cause frosting, so I am not 100% certain if that is typical with the POA valve or not.

That was not my experience growing up on the Gulf Coast. My 1970 Cutlass Supreme's A/C blew plenty cold - I had zero complaints about its performance.

 

Here is your very own thread. It really is not in your best interest to resurrect a thread that's been dead for over a decade with a question that isn't even related to the original thread. Many people will only read the first post, which is not your question, and will start answering that one instead.

 

Get yourself a vacuum pump ( ), a set of R12 gauges (Marketplace), and fittings as needed. Evacuate, make sure it holds vacuum, and recharge. It's not difficult.

 

You might check to see if the heater valve is stuck open, or if the vacuum diaphragm in it has failed. I mention this because I had a very similar issue, and found a bad heater valve. AC blew ice cold after I replaced it.

 

Check blend door too.

 

To make R134a perform well in an original R12 system, you need to adjust the POA valve and replace the condenser with a parallel flow type.

The R12 system in my 5-year-old 1963 Bonneville convertible performed perfectly in the heat and humidity of South Texas, even with four adults in the car. Olds had the identical system in their cars.

 

I remember these systems running on R12 were ice cold. I always look for the small cans at swap meets.