lsutigers93

That is the question before you, denizens of CO

1992 Trofeo, A/C still running on R-12. Got "refrigerant low" warning all winter and spring. Car sat dormant almost three months. Now "refrigerant low" warning not showing and A/C blows cold. Should I (1) find someone with R-12 to top-off system, or (2) evacuate the remaining R-12 and convert to R-134? Your thoughts, CO?

Allan R

Maybe the R12 was reacting to the cooler weather of the winter? If it was my car I would prolly take it in and pressure test. If good I'd keep it with R12 and top it off. Check the schraeder valve for any sign of slow leak.

Funkwagon455

X2 on the service valve, check actual pressures and service if needed first. Roll with the 12 until you cannot get it anymore...good stuff.

jensenracing77

it is likely just a little low. when A/C cars sit for extended amounts of time it can cause the seal on the compressor to dry out and leak a little. after it is started up it will wet the seal again and reseal. it would be best to keep it R-12 and just top it off. when you get it checked out i bet it don't take much to get it to the proper level.

Lady72nRob71

If it does not leak much, stay with R12. You can check for a leak at the service valves with a small dab of soapy water on your finger and look for bubbles.
As long as there is still pressure in the system, evacuation should not be required.
I would not change to 134 unless the whole system is getting restored.

joe_padavano

I'd say that's exactly the problem. The refrigerant low warning is based on a pressure switch. Cold temps mean lower pressure. As noted, you're system is probably right on the edge. A small top-off with R12 and you'll be good to go. Not running the A/C is part of the problem - the seals dry out and thus leaks start. This is one reason why GM HVAC systems run the A/C compressor in DEFROST as well as in A/C. Not only does this help dry the air, but it also keeps the seals lubricated in the winter.

DeltaPace77

As mentioned, I'd stick with R-12, and maybe add a little until the suction line(larger one coming from the evaporator) gets cold. If doing this, good idea giving the system a UV trace dye shot, as likely the mentioned compressor shaft seal leak. You can pick up a UV led flashlight for less than $20 bucks, for easily showing where the leak is, later on.