a/c conversion

hey guys, my 91 z28 needs the a/c recharged, but i think it might need converted to r134a. does anyone know how to do this?? thanks

The recommended way is to install the high and low side fittings, the accumulator(filter drier), flush the system and recharge. Some O rings may also need to be replaced.

I have seen people just install the fittings and recharge the system, but its not whats recommended. When you install the fittings you will have to remove the schrader core before hand. The NAPA part numbers for the fittings is 409903(low side) and 409901(high side). NAPA also sells the tool for removing the schrader core but I can't remember the part #. :smile:

Exactly what gearhead74 said.
but place extra attention on flushing the system! You will need to remove the compressor and turn it so as to drain ALL of the old mineral oil from it. Dont spare the baby on the flush either, I used 1 1/2 quarts on the condensor and hoses and another 1 1/2 quarts on the evaporator and high pressure line.
I already knew that the PAG Oil (134a) was not compatible with the Mineral Oil (R12) but learned the hard way that i didn't get the system clean enough the first time around and the Mineral & PAG oils balled up into what looked like snot & partially congealed gelatin and went right for the orifice tube and caused a restriction in the system

You're lucky thats all that happened. I had a compressor fail due to the oils being mixed, luckily I had a shop do the conversion for me, they ended up eating $600 for a new compressor plus they had to change out the expansion valve as it was full of metal, plus they had to flush everything out, ended up taking 2 days.

The recommended way is to install the high and low side fittings, the accumulator(filter drier), flush the system and recharge. Some O rings may also need to be replaced.

i dont have to change the compressor?

No, the compressors from R12 systems handle the conversion very well, just make sure all the old crap is purged from the system.

you definately will need to change all of the o rings.