AC conversion

What do you AC gurus out there think about Autofrost as a substitute for R-12? Others you prefer?
My concern is with possible degraded performance by using 134A.

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Don't know what Autofrost is, so I can't speak to that. I converted my DeVille to R134a in 1998. Occasionally the weather gets warm here in Texas, but the AC in the DeVille puts out 42 air. I don't know what 'degraded performance' you mentioned means......
Dave S(Texas)
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Autofrost is a blend of two or three other refrigerants and some kind of hydrocarbon. It's acceptable for R-12 replacement per the EPA, but not necessarily approved by GM or other manufacturers.
Degraded performance to me means warm air from the vents on a hot day while stuck in traffic.

Don't know what Autofrost is, so I can't speak to that. I converted my DeVille to R134a in 1998. Occasionally the weather gets warm here in Texas, but the AC in the DeVille puts out 42 air. I don't know what 'degraded performance' you mentioned means......
Dave S(Texas)
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Then you need to get more air moving across your condenser coils. The 134a works fine in retrofitted systems when done properly.

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Don't get me wrong. I'm giving serious thought to making the conversion. My concerns are derived from reading comments from other converters here and there on the Internet.
One suggested solution to the low air flow across the condenser you allude to is an auxiliary fan or fans. I'm willing to go with the conversion and make modifications afterward if they prove to be necessary.
Do you have other tips on converting?

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On Mon, 10 May 2004, Silver Surfer wrote:

Autofrost (R406a , www.autofrost.com ) is probably the best of the replacement refrigerants. It is somewhat more efficient than R12 (R134a is somewhat less efficient than R12) and has excellent material and chemical compatibility with R12 systems. Also, unlike the hydrocarbon blends (HC12, OZ12, Envirosafe, etc.) it is EPA legal when properly installed and is certified nonflammable, which are two very good things. I've used Autofrost in several of my own cars over the last ten years or so with very good results.
But, as is the case with *any* refrigerant other than R12 or R134a, the big "gotchya" is finding a service facility that will work with your system. If you are on a road trip and something happens, the odds are very much against your finding such a facility -- at the very least, they will charge you a hefty fee for working on your system; more commonly they will just say "No". That's because most shops have two and only two refrigerant recovery machines: One for 12, and one for 134a. Anything else, regardless of its chemical compatibility with either of these refrigerants, would contaminate an entire tank of recovered refrigerant. This is a costly hassle for the shop, and they charge and set policy accordingly.

This is a valid concern particularly if your car's system is of marginal capacity to begin with. R134a needs greater physical system heat-transfer capacity (condenser and evaporator) than R12 for a given level of performance. If a 134a retrofit is done properly but no system components are changed, you will probably notice no significant performance reduction as you're going down the road. It is when you are standing still or creeping along (stuck in traffic) that you're likely to be unhappy with the system's peformance if you like your A/C to blow ice cold.
You don't mention what kind of car you're working on. If it has a serpentine condenser, a proper R134a retrofit would include a new parallel-flow condense; these are much more efficient. Regardless of the type of condenser, adding an extra electric fan to move air across the condenser also can give an assist in low-vehicle-speed situations. Some automakers' own R134a changeover packages include whole new evaporators, too!
R12 is expensive, but it works best in R12 systems.
DS
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Dan,
Thanks for sharing your valuable insight on this subject. You have addressed all the things that have been troubling me.
PS The vehicle of concern is my daughter's '92 Grand AM.

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On Mon, 10 May 2004 11:58:07 -0400, "Daniel J. Stern"

I'd like to encourage you to use R-134. I've done several R-134 conversions, and they work fine. Shops usually have machines only for R-12 and R-134. If you bring in a R-xxx car, they will need to dump it to their contaminated unit and charge you a lot of money for that privledge.
You are much better off either retrofitting to R-134 or sticking with R-12.
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OK. I will give your advice very serious consideration. Thanks for responding.
wrote:

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