r409a is not compatable it gets too cold and will freeze the evaporator, it also needs different oil for the compressor.
is NOT a drop in fix.
I am a certified frigeration tech and tried the 409 in my own truck, sure its cold as the arctic but cycling it to keep the evap clear is retarted.
409 is the closest replacement to r12, the other gasses i would have to look up but doubt they are any better.
95 E34 530I V2.37
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