I use Duracool HC refrigerant and their PAO 68 oil in all my cars, incl 1984 & 85 300D w/ R4 compressor. I re-rubbered with barrier hose. HC works with mineral oil, so is drop-in replacement for R-12 and even works slightly better. Ignore the EPA's "must first convert to R-134A" rule, apparently a concession to AC shops. Idiots claim "explosive", but they didn't study engineering combustion like me. Never a fire reported in millions of cars.