Contour Enthusiasts Group Archives Forums General Common Interests R-12 to R-134 AC Converting

Has anyone used those R-12 to R-134 AC convertion kits you can buy at the local parts store? Do they work?

If you're talking about your 95 GL, it already has R134. The kits do work, but no cars built today come with R12 nor have they for quite a few years.

What vehicle is this for?

No, I wasn't talking about my Contour. This was for an early 90s Ford Pickup.

We did the conversion. It seems to be working OK for now.

Well, the official answer is that you must not mix R-12 and R-134a, therefore on the conversion you have to completely empty the system, which can be done using special equipment only.

I still wonder why, and what are the bad consequences of mixing the 2 gases.

I know quite a few people, who are simply filling up their 'old' system with 134a, and their a/c works fine.

If someone knows the answer please share...

Tiv

The lube carried within each type do not mix too well and can cause compressor problems....

What Terry said. Also, R-12 is slightly denser (heat carrying wise) than r-134a. This means more r-134a has to be circulating to give the same performance. In short, the conversion will have less capacity than the original. The correction to this is a faster turning compressor at a given engine RPM and larger orifices or expansion valves in the system.

Having said that, a properly flushed and cleaned system will work and the reduced capacity is noticed mostly at idle and low speeds, something some people don't mind. It is not a DYI job. If you do not recover the old refrigerant you are violating the law. If you are not certified to work on mobile A/C you are violating another law.

I am involved with conversion on larger industrial refrigeration equipment (200-10,000 HP). The cost often exceeds the cost of a new system. However, these large systems often have buildings built around them and cannot be easily replaced or the equipment is no longer manufactered so repair is the only option.

If I remember my A/C classes correctly, you will also want to swap out o-rings, and the reciever/dryer. Over time the dessicants (sp?) will consume all of the moisture that they can so it will float freely around your system causing problems. The oils between the two types are also different. The two types of systems use different types of hoses as well. IIRC, the new systems use Galaxy hose.

Sorry, trying to remember classes that I took years ago.

I had the AC in my '88 Mustang converted to R134a. I also had a "smart VOV" installed at the same time:

http://www.sherco-auto.com/smartvov.htm

I have no idea how much the smart VOV helped, but it definently cools adequately....

By the way, Ford says that replacing the accumulator is not required when converting from R12 to R134a..

Brian

I did the conversion on two vehicles and they both worked great. Replace the filter/drier, too. Make sure you follow the directions with the denatured alcohol, and drain the oil from the compressor. The conversion is MUCH cheaper than putting R12 back in.