Toyota Repair: 1993 toyota sr5 freon type, r 134 freon, r 12 freon

Question
I was just wondering what type of freon is used in a 1993 toyota sr5?  Compressor seems to work fine.  Fan is working well too.  The truck blows cold for a few min. then conks out.  Any help would be greatly appreciated.  Thank you in advance.  
Dan

Answer
All 1993 models use the R-12 freon which is getting more expensive, about $50 a pound, I would suggest changing over to the R-134 freon which is only about $10 a pound, the kits to change over are available at most autoparts stores, the R-12 is no longer available to the general public and is slowly being phased out of existance, I'm not sure what the problem with your system may be at this time but it sounds like it is low on freon because of a leak in the system somewhere.