A/C with R12 still serviceable?

Can older A/C systems using R12 still be serviced, or does it have to be converted to R134a?

There is no law that states an existing system "has to be" converted to R 134 a if a system using R-12 is functioning properly.

If it needs recharging due to a leak,and you have a source for the R -12 then consider getting it fixed.

Many technicians will try to sell you retrofit kits,but if your system is low on charge,it may only need an o ring or tightening of a fitting. Have a reputable garage leak check the system and find out an action plan for a repair.

R -12 systems in good working order will cool down much faster than 134a systems.

Beware though, that the cost of any remaining R-12 refrigerant on earth is going to be very expensive, that's why many car guys retrofit to the newer R-134a systems. Hope that helps
HR 20

with all of the above.

Another thing is you have to be certified in a/c repair to buy R-12 if you are thinking of doing the repair yourself. Unless you know someone....


Tim

Lots of places wont touch R12 because they dont have the machines for it anymore.I know the last shop I was at had R!2 and we were only like 1 of 30 or so places that had it.Let alone most dont have R12 to recharge it.We were getting 50 bucks a pound for it which was cheap.Changing to 134 isnt very hard.Usually just the conversion kit and a reciever.dryer.Did quite a few at work and almost all lasted and cooled decent.oh yeah 134 only uses IIRC 85 % of 12.You can pick up 1 pound cans at times.Just be careful we had sysyems at work that identifier said had benzyne,butane etv in it.Rocky

Thanks for the insights guys very helpful.
I am going to see if my regular mechanic can at least leak check the system.
I can get some R12, but not sure if my mechanic has a machines for it.

Hard to find restoration places that do it as well...

I don't get why you say about "diff machines" between R12 and R134... the only diff is the niple port and there are adapters for that.

At least locally, any A/C shop is able to work on any refrigerant without diff machines really

Its the oil in the R12 compared to the oil in 134A screw up the machines

Canada has, I think, R15, they don't sell 134A, read that somewhere. Maybe one can bring down some when coming to Carlisle.

You don't need a "machine" to service A/C systems, the machine just makes it easier.

A gauge set and vacuum pump are all that's needed.

https://www.amazon.com/Goetland-Diagnost...YT1H6Z9B1HSS7AS

things work different up here.

It is illegal to vent freon to the atmosphere. It must be recovered and recycled. If you cross contaminate your R12 with R134, or vice versa, then you have an expensive waste product to dispose of.

Come on, John. You're not releasing freon into the atmosphere, are you?


Tim

No, I have both an R-12 and R-134 machine but I'm not the subject, the OP want's to "service" a system with no mention of the system's status. If it's totally flat or just low, service can be performed with minimal equipment and no harm to the ozone layer.

Easy there, big guy. Only kidding.


Tim

Canada has R134 but it's harder for the average shmoe to get.

The original system was rebuilt, but it is not blowing cold. Cool at best...

I've done lot of R134a conversions. They really aren't that good. Here are a few facts to ponder.

1. R12 is a better refrigerant and operates at lower pressures. You will never get an R12 system to be as cold as it should be by using R134a. Partly because of the poorer refrigerant properties and partly because the expansion valves/orifice tubes for R12 systems are not design for the proper pressures to operate R134a. You may be able to get a different orifice tube but the expansion valves used in Mopars would have to be tuned to the R134a. I don't know of anyone who sells a replacement that is properly tuned for R134a.

2. Converting an R12 system to R134a is a temporary fix since the R12 systems are lower pressure designs. The higher operating pressures of R134a will eventually cause leaks. Even with new hoses the systems will not last as long before a leak will occur. Part of this is because R134a systems typically have 2 pressure sensors (1 low and 1 high) and a relief valve. Most R12 systems have 1 low pressure sensor only. At normal charging you are turning 800 to 2000 rpms which is not indicative to a normal driving experience. Imagine stomping on the throttle to pass somebody with the A/C on. Modern cars will either electronically detect a full throttle and temporarily cut off the compressor or when the pressure spikes the High pressure switch cuts off the compressor for you. An R12 system will simply spike to over 300PSI on the high side without much trouble. Easily over 100psi more than R12 will do and was deigned for. It can only take that so long before it leaks.

3. R134a requires approx 80% of the volume of R12. Keep this in mind while charging. Overcharging will result in very high pressures. In modern R134a systems there is usually a high pressure vent to release excess pressure. Those are not usually on R12 systems.

4. R12 uses mineral oil R134 uses ester or PAG oil. Two factors to consider about the oil. Compatibility with the refrigerant and compatibility with the other oils in a conversion. The oil is carried by the refrigerant through the system to lubricate it. R134a will not carry mineral oil so you can't use it or compressor failure will occur. However Mineral oil is not compatible with PAG oil. In a conversion you must either flush everything out and replace the compressor to remove the mineral oil or use simply use ester oil. The mineral oil will just find a low spot and settle there but as long as you do not add PAG oil it won't hurt anything. This is important because an inexperienced person/shop may add PAG since most of the OEM's use it and then you have problems.

In my opinion the two best choices are buy some overpriced R12 on craigslist or do a legitimate conversion. A legitimate conversion would be something like a Vintage air system with a newer style (high pressure compatible) compressor and proper pressure sensors.

I still do R134a conversions even on my cars because it is easily available but I expect to service the system at least once every summer.

However

I have not tried the R12 replacements like duracool, F12 and such. I tried the Freeze 12 when it was available and was unimpressed.

Anybody have experience with those I would love to hear about it.

And remember, the R-134 molecule is smaller than the R-12 so, if there are minute holes in a hose or component, the R-134 will leak out when the R-12 won't.

Here we have to watch out for some of the top-ups guys have done using that junk from the store. Because the retail sale of refrigerant in canisters under 22lbs is prohibited the stuff you buy at walmart is hydrocarbon based, usually propane/butane or something similar, which does work as a refridgerant in systems designed for it (not automotive).



We use R134A here. R12 is extinct. Legislation in place to phase down production limits of R134A to something like .5% of current levels by 2020 and replace it with R1234YF which is apparently what new vehicles are coming with. Right now R134A is a few bucks a pound but the R1234YF is in short supply and going for 50-75 a pound. Soon the R134A will start jumping up in price. We're not allowed to import the small cans of R134A either, yet nothing stops me from diving across the border and doing it on US soil.

I used 414B "hotshot" in my former B van and still use it in my Shadow. The van came with R12, the shadow being a 94 was a ba$tard configuration from Chrysler even when new. The system was designed for R12 but for the final year they switched to 134A and I remember even when new it went back to the dealership several times under warranty claims because the A/C never worked right. My dad had an A/C savvy friend put R12 in it just after the warranty was over when R12 was still mostly readily available at the time.

In 2004 we switched to 414B and it ran just the same as an R12 system. 414B was phased out a couple years ago since its still more damaging to the atmosphere. I have not tried the successor to hotshot yet since I still have several pounds of 414B in stock.

Well from what you said above about WallMart stuff thats probably why my van doesn't get very cool. How do you tell if it's the good stuff? The cans said 134A but... Should I find someone with a big cylinder?

Some things to consider. A quality conversion to R134a can be accomplished but you need some R134a specific components. The condenser is different and the H valve or expansion valve is also different. The addition of an electric fan for the condenser also helps to keep the high side pressure down when sitting in traffic.

I did the conversion on my 92 D250. I used a R134a compatible condenser, a newer R134a H valve, a new compressor, evaporator and drier. Others maintain you need to change the hoses to the newer barrier style but I didn't do that as they are not available. Yeah I know I could have had them made but my hose ends are not in great shape and I didn't want to mess with them. So I flushed the hoses really well and used PAG oil because I work at a dealership and there are plenty of half used cans of the stuff sitting around. I also added two 8" electric pusher fans on the condenser.

Either way it works well, will cycle the compressor if it's not on high at around 38*. In the 5 years since I did the conversion I have not had to add any refrigerant. The biggest problem I have with the old gal is keeping the hot outside air out of the cab. If it wasn't for that this thing would cool awesome.

ok,my 2 cents ,i have a 92 dakota that had a hose go bad ,so i bought a new hose and drier and expansion block,i bought some 134 compatible oil dumped some in by guesswork,didnt drain the old oil at all!,evac and charged with 134,works good,but it had a problem at idle it would push out some gas out of the pop off valve thats screwed in the back of the compressor,so come winter time i removed the valve and filled it with jb weld and put it back in,evac and charged the system,works fine,no leaks,this was at least 5 yrs ago,maybe more,compressor is somewhat noisy but was before i converted it,i was told by a mechanic at the time the compressor wasnt going to last very long?,as it and the truck has 348000 miles on it and still puttin out cold air
your experience may vary!1

Ive a couple cans of R12 I will never use if it would help, although I seen you posted you had some?

Thanks EV2, appreciate the offer.
Will let you know if I need it.

Thanks for all the detailed replies, learning a lot.

Another couple of questions based on above :

How can I tell what type of refrigerant was used to charge the restored system if there were no obvious changes to valves etc?

If 134a was used and can be replaced with R12, would a shop need a 134a machine to remove the 134a or can it be removed with any machine?

Would it need to be somehow "flushed out" of all previous contents before recharging with R12?

If the charge ports haven't been changed then it probably has R12 in the system but the only way to know for sure would be to have an A/C shop with a tester identify the refrigerant.

If it has 134A in the system, legally it would need to be removed with a 134A recycling machine.

Flushing the system would be required to remove the PAG oil if going from 134A back to R12 and wouldn't be a bad idea even if the system has R12 in it. I would replace the dryer also.

I prefer to use R12 in my old cars, fortunately I still have some left. I would suggest sticking with R12 if you have access to it.

Thanks for the reply Ply72rr.

The charging ports don't appear to be changed, but I was just told that 134a was used. So not sure what's in there, that's why I am hoping a shop can identify and then take action based on what's there.

Appreciate all the replies.
Will let you know what I find out...

If it has R134a in it I would keep it. It's far easier to deal with and readily available. The problem with R12 is that there aren't many shops with the equipment to deal with it. You can't recover R12 with a R134a machine as has been stated previously. You end up with a contaminated machine and tank.

is it possible to put in R134 without changing the port fittings ?

Anything is possible.

Like putting on the fittings, filling it up with R134 and removing the fittings.

Yeah, they are supposed to be non-removeable, they aren't.

you are correct, anything is possible. i wondered about this because the adapters i have used in the past, boogered up the fitting threads, supposedly making the 134 conversion "permanent". but you "had" to install the little sticker included with the conversion kit to make "sure" the conversion was complete !

I still have an unopened 30LB cyl.of R12.

Okay so according to Classic Air the original components ( compressor, clutch, filter drier and hoses ) were rebuilt to be compatible for BOTH R134a and R12.

The resto shop said they used 134a to charge system (but see no difference in the charging valves/ports).

If I wanted to go back to R12 then Classic Air would have to re-restore compressor and drier at the least...

Don't know of anyone that has a sniffer to detect R12 vs R134a.
Any obvious ways to tell to confirm?

This is likely what they did if they charged it with R134a

Why? If the components were "rebuilt to be compatible for BOTH R134a and R12" a simple change in refrigerant shouldn't be a problem.

Most current driers are compatible with both refrigerants, as is ester oil, so you can swap back and forth as desired.

Good point John.
Why can't I simply replace 134a with R12 .

I'm waiting to hear back from Classic Air to confirm.

What about the oil , per above reply each refrigerant uses a different oil , won't that require some work to flush the R134a oil out ?

"R12 uses mineral oil R134 uses ester or PAG oil."

I assume that, if it was configured to use both refrigerants, it has ester oil which is compatible with both.

Hay MONC just noticed u live up here in the HV so I guess you have the green 72 with the air grabber I've seen running around here,I have all the tools to service your a/c.

just if somebody is interested... old article but I think still valid

When doing an R134a conversion, should a guy be adding a high pressure cutout switch and/or a pressure relief valve? I don't know about adding the valve but high pressure switch doesn't look like it would be too tough to add.

Heard back from Classic Air and they said regarding evacuating R134a to put in R12 "As long as you flush the system it can be done"

So we'll see.


Thanks for posting NachoRT

Not I with the green 72 AG, but would like to me

Appreciate the offer on the tools, but am going to let the pros handle it.

Sorry to beleaguer the subject, but did you tell Classic Air that the system was "rebuilt to be compatible for BOTH R134a and R12"?

If it was, then no flushing should be necessary....simply evacuate the current gas and replace it with R-12.

They told me that.
And that l would need to flush the system

I am having someone local who works with them a lot to confirm before we do anything.

Won't be for a few weeks anyway to work me into his schedule

Forgott to say! Rockauto ( made by fourseasons ) already sells direct replacement dryers for R134a to most of the cars applications. Also the expasion valve already calibrated and with green O rings for it. The diff is just one number of the pn. I got them from them to my 74, so no need to rebuilt the dryer like the article I posted.

As far I recall but it was LOOOOONG TIME, let say the dryer PN for R12 is 24xxxx, the same unit for R134 was 34xxxx

Or something like that. i can't find the email from the customer service.

Same to the expansion valve.