Air conditioning conversion from R12 to R134


I have a 1973 pontiac firebird with factory air conditioning that doesn’t work, probably because of a leak. What do I have to do to convert it to an R134 system that will be as cold as a well functioning factory R12 unit?


Take the car to a shop that specializes in automotive AC systems. They can do the conversion PROPERLY, and when it’s done the AC will work as it should. I had this done to an old RX-7 and the AC worked better than new.

This is NOT a do-it-yourself project, no matter what it says on the conversion kit at the auto parts store. If you want it done right, and you want the AC to work, pay an expert to do the conversion.


I agree you should take it to a good shop. Also, you do not have to convert it to R-134a, you can have it fixed an recharged with R-12 (currently about $50/pound at a shop). Ask them about the cost difference and the performance difference in your particular car. The success of R-134a has a lot to do with the size of your condenser and evaporator.


Google “Freeze 12”, buy a recharge kit online, and simply recharge your system as if it were R-12. If your system is completely empty, you will have to find and repair the leak first.


Personally, I would not use any of these “alternative” coolants. Do yourself a favor and ask your shop if they will service an AC system with anything other than R-12 or R-134a. You may have problems getting these systems serviced.


Repair the leak first. Your car uses the A6 compressor and replacing the shaft seal is common, especially considering the age.

There should be no problem converting to R134 and it will work fine.
Converting does not mean simply using one of those all-in-one kits, unless you really know what you’re doing and looking for.

The pressures are critical but should not be a problem with this system. Any pressure problem snags caused by the use of 134 usually occur with an orifice tube system (easily worked around), which your car does not have.


In my experience, Enviro-Safe refrigerants are some alternative refrigerants that work well. It is usually not even necessary to change the oil to use Enviro-Safe.
Note that R134a is also an alternative to R12. The only refrigerant that is 100% compatible with R12 systems is R12. The system may need to be modified to use other refrigerants.