My car still has R-12 and original compressor. It only gets very cool, not cold like the new AC systems. I had it checked, only a little low, so he topped it off with Freeze12. My AC guy says the system is full and R-12 pressure is good and this is as good as it gets. He says R134A won't be as good as what I have! Do I need an upgraded compressor? Do they make a better compressor? Can I ever get it to blow cold?

R134A will not be as cold as R-12.

134 will cool...eventually. R12 cools quicker.
IF the interior of the car is tight, and there are NO outside air leakages into the cabin, AND there is a heat barrier installed, AND all of the ductwork for the A/C system is there, connected, and sealed properly, then 134 will work great. The problem is getting all of the above in a Corvette!
Bottom line is the system needs to be in good working condition first. No type of refrigerant is gonna cool well if there are leaks in the airflow, or hot outside air getting into the cabin.
I've converted MANY A/C systems to 134 over the years...some systems/cars work way better than others.
The system in my 'Burban, with rear A/C will freeze ya out...eventually. It just takes a while to get it to that point. The last Cad that I converted would freeze ya out in just a few minutes.
You will eventually wind up converting to 134, but...as long as it is still working, stick with the R12. If you wind up having to open the system up for repairs, then that's when the conversion should take place.

I had my 82 converted to 134A last summer.  The A/C didnt work when I got the car and it needed several components replaced anyway so it was the right time to convert.  The A/C gets cold, but not to the point that you can hang meat in the car.  In the 90-95 degree heat with matching humidity in the South, it is adequate.  I have all of the things Joel mentioned except my heat barrier could be better.

During a pre-trip checkup on "The Beast" it was found that the A/C condenser needed to be replaced.  The options laid out were "Pay me now or pay me later" for the conversion.  With R12 at $90/lb and R134 at $20/lb (at the stealership) we decided to make the switch.

Does it start out nice and cold but gradually get less cold as the motor fully warms up? Could be the cutoff valve in the heater hose not working. Air blows cold while cold coolant is still flowing through the heater core.

I've replaced my heater valve with a manual for complete shut-off so that is not the problem. The air coming out of the ducts is not cold or really very cool, just pretty cool. It is enough with the system running on max air and full fan on a hot day. It really hasn't been that hot here this summer. I've sealed all leaks and put a reflective barrier inside on T-tops and it will just keep you barely comfortable on a hot sunny day. I bought the car in Houston to drive back to Arkansas. Before I got out of town the T-top heat barrier was already duct taped up. I will check my duct work for integrity and I guess that is about all I can do for now.

Thanks for all the input!

terntes.

When you had the AC serviced did they just top off the freon or did they evauate the system and pull  a good vacuum? It sounds like there might be some moisture in the system. If the pressure is good and not gettin cold there is moisture or a blockage. That's assuming all the thing Joel menioned are good.

Scott

   To the best of my knowledge he checked the pressure, it was good so they added a can of Freeze12 and charged me $55. That stuff is not supposed to be compatible with R12, but what do I know? It might be moisture or I've heard it might be dirt on the cooling core? It will be very hot here for the next  two months and I drive my car every day, so I'm going to get it fixed, no matter what.

My suggestion being an a/c tech, PLEASE stay away from so called drop in ref. Stick with either r12 or 134a. All the others are a corktail soup of different ref. Plus I would be really ticked off if I ran it into my recycling equip. They're all a contaminant. my7T12007-07-14 05:55:50