How to tell if car is R-12 or R134?
 

Without having to take my car into the shop, how can I tell if my car has R-12 or has been converted to R-134?

What year is your car? Most of the time someone will label the compressor as 134A or you can usually tell by the quick disconect fittings. Should have a red one and a blue one ( the Caps that is).

Shoot us a pic of the fittings and I can tell you if its 134A or not

Also, another way is that instead of being weak, with 134 your A/C will completely suck:)

so true...

I'm assuming its R-134 since it does completely suck but they car is a 1980 so it should have had R-12 but I dont know if it has been converted.

If it has not shoudl I convet it? From the comments on the R-134 I guess not.

R-12 fittings are outside-threaded schraeder valves. R-134 are quick-disconnect.

If the PO was a pelican you could have one of those propane isobutane cocktail mixture in there. Do a search and you will find advice on this board how to fabricate an adapter to charge the system with this mixture, or you could have freeze 12 in the system. Good luck finding a shop that will work on the system if it contain something other than R12 or R134a.

If you haven't done any upgrades on the AC I would stick R-12. Do a search and you will find lots of info on this topic.

Is this because it's a conversion or is it your opinion that R-134a is simply not suitible as a refridgerent? My 93 C2's A/C is R-134 from the factory and works perfectly... :)

911 A/C systems using R-134a can be set up to chill you to the bone. It ain't rocket engineering but some money is required for more modern parts (there are only few systems that will be helped by the "cures in the can") and it takes effort beyond whining and sweating. The first step is periodic maintenance which many (maybe most) people fail to do.

R-134a works fine in systems designed for it. The Problem with early 911 AC systems is that they were woefully lacking in both condensor & evaporator area as well as sufficient air flow across either.

Quite of few people on this board have modified their systems to address these problems and have excellent performance with 134a

It is a fact that 134a is not as efficient as r12 so we give up a little performance using it. Your car's front fender condensor is why you have pretty good air with 134a.

The 964's are a giant leap forward in 911 a/c in my opinion but the older cars with too little condensor area and an evaporator in the smugglers box were not that effective using r12 to begin with.

Its just awesome the things you can learn on this board. I was wondering what mine had and niner11 naled it for me - Thanks!!

"It is a fact that 134a is not as efficient as r12".

If judged solely as refrigerants, not true. In a system optimized for R-134a, R-134a will out perform R-12.

Here we go again. You are right, I can optimize my system by bolting a condensor the size of a pizza box on my roof. Short of that I will praise r12

Press the release button, watch the gas escape......if a bunch of Democrats show up threatening to fine you, it's R-134

Refrigeration effect of R12 is 105.7 Joules/gram of refrigerant while R-134a is 134.8 J/g. Coefficient of performance (efficiency) is the same out to three places for the same suction superheat. For a given thermal capacity, the R-134a systems require about 20% more system internal volume due to the refrigerant being effectively less dense. If your 20 plus-year-old condensing system is inadequate with R134a it is likely to be inadequate with R12. Cheers and chills. Jim

I'm sorry, you broke up after Joules/gram......:)

Although, once upon a time I worked in Arkansas I've forgotten the "redneck" units for refrigeration effect. Best I can do now is a conversion into the good "Christian" units of BTU/lbm.:D

You could moonlight as a Domino pizza driver with that setup and stay cool. Fastest pizza delivery vehicle.

Jim, I don't want to get too far off topic but I was wondering if you might be able to come up with numbers for some of the other choices we have for refrigerants.

I know there is Freeze 12, HC something, etc. Knowing that there is no holy grail of refrigerants is there anything else out there that makes sense to use.

BTW, I like the idea of delivering pizza in the 911. I could write off an entire Griffiths setup.

Thanks, Chuck