Re: Considering buying a 164, ac questions
See my previous postings on RS24, as fitted to my 1990 164 by an air-con specialist. An R12 drop-in requiring no mods to the system, and ice cold.
You can also get off the shelf product drop in product called Freeze-12 in the States, though not tried it. Comes as a kit with its own style Shraeder valves, oil, leak seal and refrigerant.
Be careful if an air-con "specialist" is filling your car A/C with propane. Yes propane will work as an A/C gas, though is too flammable to consider using in a vehicle where there are risks of a collision venting the gas to hot exhaust and sparking metal/electrics