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R12 substitute experiances?

I have an '86 Accord that uses the old R12 stuff. My A/C still appears to work okay-- the fans turn on, the compressor goes and the air coming out of the vents eventually definitely does get somewhat colder than when it’s only on RecirculateVent, but it doesn’t really get cold enough to be helpful on days that get above the mid-80’s. It also hasn’t really gotten much worse since I’ve owned it for the last three years or so, so I’m assuming that it just needs a recharge and isn’t leaking too bad.

Since I live in a (relatively) cool area, I don’t really want to plunk down the money for doing a R134 retrofit, but I’ve been wondering about Freeze-12 or any of the other supposed R12 equivalents. I’ve been finding kind of mixed and ambiguous reviews. Does anyone have any real world experience using them?

The way it was explained to me, one of the worst things about those replacements is the problem with their mixing with the real thing when the system is eventually purged. The tank in the evacuating machine will have R-12 in it. Introducing another refrigerant to that tank will contaminate what’s in there making it illegal to reuse. I have not used them, nor will I.

I used to have an '88 Accord that also used R-12, and it was really in need of a recharge. I got some Freeze-12 (no other alternative, I was NOT plunking down the money for an R-134 conversion), and it seemed to work well enough. Didn’t cause any trouble that I was aware of, and certainly made the A/C colder.

It’s supposedly completely okay to mix with R-12, but I never had the system totally evacuated so I can’t comment on what MG described.

Agree; if you have a slow leak, just top it up with Freon 12. A proper conversion costs a great deal of money; I was quoted $950 for a Caprice, including a new compressor. I just spent $50 for a top up and was good for another 2 years.

AFAIK, it is still legal for air conditioner people to sell R12 properly “remanufactured” from the gas recovered during servicing. It’s expensive. But you may not need a lot of it to top of your system which sounds to be in decent shape. Why not call an automotive air conditioning guy? Getting better cooling may not be as outrageously expensive as one would assume. … or the cost may be extortionate. Probably only one way to find out.

Wall-Mart sells a kit with R134 that is compatible with R12. It’s about $30 with 2 cans of coolant and filler. My 88 Accord has a slow leak. I put a kit in 2 summers ago and it works fine. One can was enough to fill the system each year. This year I got a can of R134 ($11) with a stop-leak additive that also says it’s compatible with R12 residue. Maybe this will slow the leak, but I can live with putting one can a year, if I still have the car next year (a friend is interested in buying it).

I have used "Freeze-12 in 3 older R-12 cars with very slow leaks and it has worked fine. Just ad it to the R-12 system as if it was R-12.

“Professional” A/C shops get all in a tizzy over it because if they evacuate your system (they won’t touch it if they know there is Freeze-12 in it) they will contaminate their precious stash of R-12 they have been stealing from people like you and then re-selling it back at crazy prices…So if you MUST visit a pro after using Freeze 12, just remove (open) the service ports and empty the system, solving THAT problem…

Before everyone jumps on me for even suggesting such a thing, please remember that sooner or later, it ALL gets dumped into the atmosphere one way or the other…

You know I was wondering about that very thing earlier. Since it seems like the “proper disposal” technique is to recover and reuse it, it seems like the only way any of it gets taken out of circulation is for it to leak out.

Not that I want to give anyone any ideas, but if they were really serious about keeping the stuff out of the atmosphere, you’d think that it’d make more sense to bury the remaining stocks of the stuff out in the desert or something instead of storing it in an ever-aging fleet of pre-R134 cars.

At any rate, when I was considering this last summer, it seemed like I saw Freeze-12 a lot of places, but I haven’t been able to find it in the couple of places I looked today. I even ventured out to the walmart, and I think I saw the kit that circuitsmith described, but I didn’t see anything on it that implied that it would be compatible with the R12 (although the “conversion” did seem to mostly be step 1: evacuate old stuff, step 2: put in new stuff). I guess it might be worth a try, although I’m kind of wary about risking what limited cooling I have as is.

This was my preferred option, but there’s really not much in the way of a good auto AC specialist here in town. All the shops I asked about it just recommended doing the retrofit. I am driving to Chicago next week (hence the wanting to get the AC to work) so I might just suffer across the plains and see if I can find someone there who could top it off.

You can buy a 3-can kit of Freeze 12 online (google it) for around $60. This includes a can tap and fittings to install. The product itself is about $10/can.

Has anyone tried making up a tap adapter and simply installing R-134a directly into an old R-12 system that still has some pressure in it? Are all the horror stories true?

I’m no A/C expert, but supposedly very bad things happen if you mix the two refrigerants. They use different types of oil, and the combination of differing oils and refrigerants supposedly frags compressors and generally makes a mess of things.

I’d only try it as an experiment on a system that I didn’t care about ruining. Not recommended on one you’re genuinely trying to get working right.

“Has anyone tried making up a tap adapter and simply installing R-134a directly into an old R-12 system that still has some pressure in it?”

I’ve used an R-134a kit from WalMart labeled for doing just that for 2 years with no problem. See my post above. Comes in a tall blue box IIRC.

I don’t understand why everyone keeps complaining about the cost of retrofitting for R134a refrigerant. Based on the conversion kits they sell at Walmart, the only conversion is to add an adapter to the filling port. The cost should be minimal.

The best way to keep your AC system operating efficiently is to recharge the system with the refrigerant that originally came in the system.

If you use Freeze 12 to recharge the system, you blend two refrigerants. That’s against EPA regulations. If you should ever need future service on the AC system where refrigerant recovery is required, nobody will touch the system because of the blended refrigerants. It’s also against EPA regulations to recover blended refrigerants into a refrigerant recovery machine.

Using a 134A refrigerant convertion kit in an R12 system is also against EPA regulations. Again, that’s the blending of two refrigerants. R12 systems use mineral oil as a lubricant. R134a uses either PAG or ester oil as a lubricant. These oils don’t mix with R12. And the mineral oil doesn’t mix with the R134a. So mixing the two oils can result in lack of lubrication to the compressor, resulting in compressor damage.


I am wondering whether the mineral oil, PAG oil, ester oil compatibility, incompatibility are as serious or important as we have been led to believe…Many, many systems have been converted from R-12 to R-134a leaving most of the original mineral oil in the compressor. Sometimes a can of ester oil is added to “protect the compressor” and sometimes not…But it’s almost impossible to “purge” or “flush” the mineral oil out of the system unless it’s completely disassembled, and few shops do that…So that leaves the importance of “having the right oil” open for discussion…Freeze 12 claims their product is 100% compatible with the mineral oil found in the systems it was designed to be used in, even though Freeze-12 is mostly R-134a blended with a small amount of a second refrigerant to produce a mixture that mimics the properties of R-12…The “conversion kits” sold in Wally-World make no mention of oil incompatibility and thousands have used these kits with varying degrees of success. Many complain of poor cooling performance but few complain of blown compressors…So perhaps the importance of oil type is somewhat overstated, designed more to prevent refrigerant mixing than preventing compressor failure…


This paragraph pretty much answers the compressor oil debate…

“R-134a also requires its own special type of oil: either a polyakylene (PAG) oil or a polyol ester (POE) oil. The OEMS mostly specify a variety of different PAG oils because some compressors require a heavier or lighter viscosity oil for proper lubrication (though General Motors does specify only a single grade of PAG oil for most service applications). The aftermarket generally favors POE oil because POE is compatible with both R-12 and R-134a and unlike PAG oil it will mix with mineral oil. Mineral oil, as a rule, should still be used in older R-12 systems.”

Freeze-12 is a mixture of 70% R-134a and 30% R-142b How they can claim the product is compatible with mineral oil is a mystery unless the R-142b can carry enough oil to satisfy the compressors needs…

The high cost of conversion perception comes from the early days of R134. It used to be believed that the entire system basically needed to be changed over, and that higher compression of the refrigerant was necessary for the system to operate satisfactorally. This has proven to be largely untrue, although some loss of effectivity of the AC system needs to be accepted.

My understanding is that the belief comes from the R134’s relative inefficiency. My understanding is that it simply does not work as efficiently as R12.

R134a refrigerant operates at a different pressure curve than R12. So R134a requires a higher pressure to have the same effect as R12 refrigerant.


True, but it still works with the same pressures, just not quite as well. In hot climates that could make a difference, but up here in NH it did not turn out to be as big a problem as first believed.

However my post was to provide some insight into the reason it was originally thought that an entiire system conversion was necessary. After having seen numerous successful conversions done without replacing the system, most folks up here stopped bothering to do so.