R406A is supposed to be the only blend that will work with R-12 and mineral oil.

The whole problem is that 134A only mixes with PAG or Ester oils and these oils do not like Chlorides.

Here is a link to a company that sales the stuff but I list it only for the tech info.

http://www.autofrost.com/hotshot/index.html

http://www.autofrost.com/index.html

What happens when one uses a Chlorinated Refrigerant (i.e. CFC or HCFC) in PAG oil made for R-134a systems?
PAG OIL (Polyalkylene Glycol) Refrigerant oil made for HFC (e.g. R-134a) systems CANNOT tolerate even minute amounts of chlorides, such as from aluminum chloride "coatings" inside pipes that formed from the original R-12 charge or having over .5% or more of "chlorinated refrigerants" in the system. Chlorinated refrigerants include the CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). R-11 (flush) and R-12 are CFCs. R-11 is extremely damaging to PAG oils, more so than R12. This information dates back to 1990-1991.
HCFCs include R-22, R-124, R-142b (blend components used in R-406A/Autofrost, Frigc FR-12, Freeze12, Freezone RB276, R-414A (GHG-X4), and R-414B (ICOR HOTSHOT).
Use of any of the above refrigerants or blend components in a system with PAG oil will mostly likely destroy the oil. There have been some attempts to make PAG oils to withstand chlorides, most notably the "Daphne" brand. The test sheet I saw still showed slight darkening of the PAG oil (Daphne brand) when mixed with R-12. Other brands of PAG oils turned black. When one services a car, one usually does not know if it contains Daphne PAG or not.
Not all CFCs/HCFCs are the same reactivity in destroying PAG oil. R-11 (the old "flush") is the most reactive by far, and R-124 is one of the least. Actual break down times will be related to ambient temperature and operating temperature as well.
A 16fl oz bottle of GM Delco "Refrigerant Oil R134a Systems" (other numbers on bottle: 1#12356151 Gr. 8.8 1#15-11 was purchased at a local auto parts store. The label also had the information "Contains: Polyalkylene glycol-New Jersey Trade Secret, Registry number 027586004-8550P).
A newly developed PAG oil, called "Daphne" or "Double end capped" PAG oil has been shown to be able to withstand chlorinated refrigerants, even R-12, MUCH better than conventional PAG oils.

Wow awesome news on that. the mechanic did not use PAG Oil but used mineral oil such as in R-12. Freeze 12 claims it uses mineral or ester oils. PAG oil is different from mineral and ester therefore wasn't used.. (ester being synethic for R-134a)

I'm the one that installed Freeze-12 in early July. I evacuated the r12 and it worked great until this evening i went out and it has leaked out again. I thought I had a slow leak before but it was evidently faster than i thought. Possibly it has eroded the seals in the compressor, but i doubt it. Now i wish i had converted to 134 so i could use my 134 leak tester.

Well then that answers my question, Thank you for your response. I will Immediately have mine serviced back to R-12 and not this Freeze-12 stuff. You see what happened is that R134 ruined all your seals because its not designed for R-134a and converting to R-134a is costly, believe me. I looked into it. You would need to replace alot of things and seals. When you can just go to the Dealership and have them recharge your system when its not leaking to R-12. which you should have done. I will not have this freeze-12 in my system knowing what happened to you. thank you for your information.

Thank you.

You expected me to pour in a few hundred dollars of R12 when i didn't know if it would all escape? No one here mentioned before that Freeze12 had 134 in it, and i never found a site that said it did.

Ron350'* post indicates that minute amounts of 134 refrigerant oil in old r12 systems causes problems, not the other way around. Can someone else verify that Freeze12 would have increased the rate of my leak?

I may have found why it leaked out so fast after my conversion to freeze12. I had to install an adapter fitting with its own schrader valve on the high side so that my guages would fit, which meant I needed a different valve stem cap which i found in my dad'* spare parts bin. However today while recharging it I noticed the O-ring in the cap was gone, so i replaced it. I'll let you know how long it lasts this time.

If I have to convert to 134, I will replace EVERYTHING: compressor, evap, condensor, and lines. In one of our tractors, we tried draining the oil out of the compressor and switching oils, but the compressor later failed, so i'm not going that route again.

JDB what kind of 134A leek detector do you have?

http://www.hc12ausa.com/hc12/index.html

A possibility. I used it to recharge my daughter'* 91 GP 2 years ago. Still working fine.

Halogen

Halogen leak dictators are supposed to work on all refrigerants aren’t they?

On all this R12 replacement stuff you have to read between the lines. At $8.00 a can 134a is hard to beat as a R12 replacement.
I know of several R12 cars that have had the 134a put in as the R12 leaked out and are still working. If I were to try that my car would fly around the room backwards. LOL

Archon there are lots of cars using Hydrocarbons (Propane on Butane) to replace R12 but it seams to be hard on compressors. As far as cooling goes HC’* work fine and would be a good replacement for R12 if they did not burn. I have read that HC replacements are banned in several states for automotive use.