[bowman1964]

ok well if it has r12 you only have a few choices. r22 r502
you see r12 r22 r502 all use the same oil (mineral oil) so you can go with any of the 3 .but r502 is the coldest,but it boils so low it can cause the compressor to overheat if the condensor cannt handle the heat.so i would recommend r22 .it isnt priced too bad and any ac repair shop can charge it.
you can recharge with r134a or any of the other refrigerants like r404a but you will have to change the oil ,which can be a pain on a fridge.
i would reconmend r22.

i see you have been in a few differant forums asking this question .everyone giving you opinions but none of them have actually used r502. i use it as r22 r12 .so i am telling you the facts not just what you can read in a fridgerantion chart.
some of the guys mean well but they think they can learn the entire refridgerant field in a matter of months.

i hope i helped a little