A/C Dead, options?

[gadget73]

There are two kinds of R12 high side port, the Ford one, and the "everyone else" one. If what you have doesn't fit your car, you got the "everyone else" fitting. I want to say its 1/4 SAE flare vs 3/16". I had to buy that adapter to work with the un-converted system on my Mark VII. Same problem with conversion fittings if you ever do an R134a swap on one.

Make sure you get refrigerant oil for the system you are flushing. All of it will go away. I expect hydrocarbon refrigerants want mineral oil but not 100% on that one so confirm with who makes it. I'm running mineral oil with my bastardized propane/butane charge in the Mark VII. Mineral oil is what R12 ran, so no worries about compatibility.

May as well get an O ring set while you're in there, and just change every O ring in the system, or at least do the fittings you disconnected to flush things.

[sly]

Ester oil for change over from R12 to R134a. It's compatible with both and won't cause acids to form. Change accumulator and o-tube, flush evap and condenser, add 2oz oil to evap and condenser. Best to drain the compressor and add 4oz oil to it. Once the system is assembled and evacuated, rotate the compressor by hand a dozen times before filling the system. Did that with the Mad Marquis and it left my possession 5-6 years later (IIRC) with no issues with the system.

[sly]

Also... AC flush is EXTREMELY EVIL STUFF AND WILL BURN YOU. Wear some severe chemical gloves. Nitrile gloves do absolutely NOTHING. Washing cuts in gasoline feels better than AC flush on good skin.

The gloves will be damaged if they come in contact with the stuff. It has a very low flash point too.

[Grand1]

Excellent information for an AC virgin in a similar circumstance as kish with four cars without AC. It seems that my 87 CV is r12 and I have read several sources that state the conversion can be a questionable tactic.

134a is more hygroscopic than R12 and is prone to more moisture absorption = the seals must be much more tight than r12 hence the whole oring issue. R12 gets more cold, from what I read, looks like it is still attainable as well. Is really bad for the enviroment? What footprint does one leave for the conversion to 134A?

[Kodachrome Wolf]

Excellent information for an AC virgin in a similar circumstance as kish with four cars without AC. It seems that my 87 CV is r12 and I have read several sources that state the conversion can be a questionable tactic.

134a is more hygroscopic than R12 and is prone to more moisture absorption = the seals must be much more tight than r12 hence the whole oring issue. R12 gets more cold, from what I read, looks like it is still attainable as well. Is really bad for the enviroment? What footprint does one leave for the conversion to 134A?

R12 has CFCs and is bad for the ozone. It's also not easily attainable, and fairly costly to get the real stuff. There's stuff like what the Canadians can get like Freeze-12, HC-12a, etc, but the chemical compositions sometimes include butane, propane, or other compressed gasses for the refrigerant. Supposedly that stuff will play nice with R-12.

In the US, one is not supposed to use flammable gasses for refrigerants, but in theory one could charge their entire A/C system with propane and it would function, just there's the flammability risk (and maybe getting caught).

Regarding R-134a, converting is not a horrific issue. If you have any remaining R-12 in your system, it should be recovered properly. Now would also be a great time to install new A/C hoses and install new o-rings with the system discharged. Fit a new accumulator, add the appropriate ester oil as required, install the adapter fittings from R-12 to R-134a, and have the system vacuumed down. Once the system is properly holding vacuum with no leaks, it can be charged. R-134a uses roughly 80% the capacity of R-12, so keep that in mind while charging. Once that's done, the A/C should be working well. You might need to adjust the screw inside the clutch cycle switch to allow for it to cycle properly with R-134a.

My '87 has been converted for some time and stays plenty cold.

[gadget73]

My Continental is an R134a conversion. The Mark VII with the same AC parts is a propane/butane mix. The explosive gas bomb system is a hell of a lot colder. I really should flush that out and charge it with some known potion since its a mix of propane and butane that I knocked together myself from lantern bottles and camping stove gas but it was done for leak checking purposes. I didn't really intend to leave it in there but quite frankly it works pretty well. I may actually convert the Conti to that. Fox AC systems are marginal at best and they don't do 134a conversions amazingly well.

The Towncar works just fine though. Bigger condenser is my best guess for that. Would likely do even better with a modern multi-pass one in place of the original 80s design.

[friskyfrankie]

Usually better to replace an older system with the same stuff it was designed for. Less parts changing. If that refrigerant is not available get the closest (legal) one you can get. Alternatives ARE usually to be found.