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Freeze 12 and the others are like running Linux or Beos. It works for some who want to devote the time and effort. They may work better for those who master them than Windows. But options and support are limited by the relative rarity of the products and the regular user will end up unhappy.
R134a is far from a perfect replacement for r12. First, many older cars require replacement of the receiver/drier because the older driers used a charcoal filter which will deteriorate with r134a over a few months and destroy the entire system by coating everything with a black sludge. Also, the mineral oil used with r12 won't circulate with r134a and new oil, such as ester oil, must be added to a conversion. R134a runs less refrigerant at a higher pressure and will strain the high side on some systems which were designed for r12. I think r134a takes longer to cool down a hot car than r12.
Replacing the expansion valve in a 9000 conversion really isn't necessary as it is in some accumulator systems which use an orifice tube. Anytime you open a system, or really anytime the system is low, you should evacuate and vacuum to remove the moisture so this is not so much a function of the conversion as general good ac practice. I would flush a conversion whenever possible to get out the old mineral oil because it has the potential to cause trouble if it reaches the compressor. Flushing also gets out crap that has accumulated in the system over the years. Really, there's no reason not to flush except lazy.
The most significant advantage r134a has over these other products is that it is universally used. The problems are known and the solutions are not hard to discern. Also, the equipment is cheaply and widely available. If you try one of these other products and want professional help, you might have a hard time finding it as professional ac people are reluctant to touch a system which has used anything but r12 or r134a.
I have had mixed success with r134a conversions. My 1991 9000 converted easily and blew cold until it developed a mysterious leak. I spent a ton of money replacing parts until I found the o-ring with the hairline crack. This started me on the ac journey and I learned a lot. I converted a Ford Explorer which did not seem to like the elevated high side pressure of r134a and never cooled better than ok. I had an Alfa Milano professionally converted because I did not have time to do it myself. I bought a parallel flow condensor for that one but it was never really ice cold. Right now I have a Mercedes which is still r12 and I am trying to find a can of r12 to give it a boost. I could convert it but I just don't feel like messing with it. I would consider trying Freeze 12 or one of the others but if I was going to invest the time learning about those products, not to mention the potential to buy more tools, I would just do the r134a conversion.
posted by 64.222.108...
, Fri, 10 Jun 2005 08:11:40
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