For those who care, Cessna aircraft issued Service Newsletter number 04-10 which says that Hot Shot R414B refrigerant is now FAA approved "is a cost effective alternative for converting from an R-12 based air conditioning system" and is "UL classified, nontoxic, nonflammable, provideds adequate oil return at all temperatures, requires no unnecessary oil changes, does not require system modification, and utilizes existing R-12 servicing equipment."
cool I just tried freeze 12 in my 77 truck and was not happy with the results. I switched to 134a and it has been working great. I do have a newer style rotory pump. I might have to try hot shot in the new car.
The one issue that I have been made aware of in my air conditioning research is that when you use a blend like R414b, you want to make absolutely sure that you don't have a leak. This is because the separate components of the blend will leak at different rates and eventually the charge in your system will no longer be the proper blend. What are the consequences? I am not really sure...I decided to pay $20 to take the online test a couple years ago and get my 609 certification so I can buy R12. I also picked up a used recycle/recover system so I can save the Freon(and avoid violating Federal law ) when I need to open the system. Anyway, I would guess that if the blend were to become unbalanced from a slow leak, either the system would not cool very well or the oil might not return to the compressor anymore and then SCREEEECH....BOOM! Also, technically you would not be able to "top off" a system with a slow leak...the only way to get the proper blend would be to remove the refrigerant and then replace it... Just my . I dunno...R414b may actually be the best stuff in the world...I don't want to knock it without trying it, just wanted to mention what I have read while researching using different refrigerants.
