Mike - FR-12 is an ideal replacement for R-12 and just this year I'm learning that R-134a is being replaced by this rerigerant, (by private owners), because of it's lower high and low side pressures, compatability with internal components and general friendly properties. Also, the government will soon be ordering the auto builders to phase-out R-134a, but I don't know, yet, what the new one will be....Bob Harris Subject: IML: A/C R134a vs R12 > > Other question: In instruction for the compressor > > written it's suitable for R12 and R134a is it > > possible? There is no direct drop-in replacement for R12 as of this date. R134a can be