Read this elsewhere (not my worrds):
- "R134a attacks the nitrile butyl rubber found in R12 system hoses."
- "R134a requires special carbon-filled iso-butyl rubber parts." (hoses and 0-ring seals used throughout the system)
- "The conventional silical gel dessicant used for R12 may break down when exposed to R134a. R134a requires a molecular sieve type dessicant."
- "R12 systems use a highly refined mineral oil lubricant. R134a systems use synthetic "PAG" lubricant which can cause swelling or foaming of conventional rubber gaskets and seals used in R12 systems. Be sure to special RBR rubber O-rings during assembly and repairs."
5, "R134a hoses not only have the special RRB rubber, but also have an impermeable inner lining of nylon to reduce seepage of the refrigerant and to prevent moisture entry into the system."
Now even if you spend all the time and money for these special hoses, O-rings, dessicant, etc., you still won't get the cold 37-42 degree F air coming out of your AC vents like you did with R12. You'll get more like 45-55 degree F air, which means the interior of your car will be about
10 degrees warmer on a hot day if you convert to R134a.