Stock compressor,mod for 134a ?
• It's highly compatible with existing systems
• It's one of the two legitimate refrigerants for A/C systems in old cars (anything else in your system and any shop worth letting touch your car will order you off their premises)
• It's safe
• It's legal
• It's cheap
Those are five very sturdy reasons.
R-134A has been outlawed for years in many countries and phasing out in 2017 in the U.S.?
It's being phased out for
new cars, but will be available (and inexpensive) for servicing existing systems for a very long time. The refrigerant being phased in for new cars, HFO-1234YF, requires extremely different A/C system hardware than R12 and R134A.
I have Duracool HC refrigerant in all of my vehicles now.
That's a hydrocarbon blend. It does not belong in your A/C system, which (unlike your fuel system) was not designed or engineered to carry or transport a highly flammable working fluid. Using this stuff is not clever, it's super extra foolish for all the reasons already covered.
Of course those who market it promote it as completely safe, don't pay attention to any of those scare stories, blah blah don't pay attention to the fact it's not approved, blah blah conspiracy by the refrigerant industry blahbitty blah blah blah. Because yeah, highly flammable hydrocarbons under high pressure are safe, because, um, because, uh, because, um, it's made with special
smart grades of isobutane and isopropane that, um, they, uh, know not to explode when they're in an A/C system!