Nice....
Looks like the EPA has resorted to the honor system for the sale and use of R-12.

Thanks for the link!
Elm

 

oh my gosh people! corvette central has a conversion kit for $40. from what i know the R12 is more expensive and getting harder to find. i'd just convert to the new stuff and be done with it. my guess is, that by the next time it needs recharged everybody will have cnverted to the R134a and you will have no choice but to convert your system. in my mind it is delaying the inevitable.

 

This comment is based on experience:
I have several vehicles designed by the factory to use R12 that have been correctly converted to R134 and they don't work very well. Some people who have converted claim it works fine. So I converted another one of mine... it doesn't work fine. I'm not saying you can't make R134 work in a system designed for R12, but it's not necessarily a "convert & forget about it" operation. Pay yer money, take yer chances. The flip side is, if a system that was originally designed to use R12 is filled with R12... it will work properly.

This is an opinion:
I don't think R12 will ever be 100% eliminated. There is a large contingent of people who disagree with the Montreal Protocol in as much as it was simply thought to be a "sky is falling" maneuver by DuPont to regain market share of patented products. Their patent ran out on R12 and voila... they had a replacement just waiting in the wings. We can argue forever on who is right (as has already been done on this forum) but countries who don't have to bow down to the bullies can continue to produe R12 as long as there is a demand for it. You can find it on the internet no problem. It just costs a lot.

http://www.amazon.com/Holes-Ozone-Sc.../dp/0962813400

 

While I don't know what motives were behind the banning of R-12 production in the states other than what I've read, I do agree with Tom in that a system designed for R-12 will never be as efficient or effective when converted to R-134a or whatever.

R-134a doesn't have the same cooling properties as R-12 and needs to run at higher pressures than R-12 to be effective.
Other than replacing the hoses on an R-12 system to hold the R-134a without loss through the lines, the system is sized and designed for R-12.
Unless you size the system appropriately and run the pressures required for R-134a, it will never be as effective..Period.
If you live in a climate that isn't too extreme on temp and humidity, you may be satisfied with the conversion- But if you live along the Gulf coast or in the Midwest where the summers are hot and humid, you will most likely be disappointed.

If you want to convert, the best thing would be to remove the entire R-12 system and replace it with something that was designed to run on something else (IE a Vintage Air system).
For my taste, I'd rather pay the $40 a pound (or whatever it is now) and top off my R-12 system every few years when I need it.
Parts to maintain either system (compressors, evaporators etc) cost pretty much the same, it's only the Freon itself that has a cost delta.

Personally, I'll run my R-12 for as long as I can.
Elm

 

I agree with just topping off with some R-12, as 134a requires different oil, and likes a larger condensor. Reason R-12 was phased out, has high chlorine content, that can get into the atmosphere protective ozone layer, and eat at it. In reality, didn't prove to do anything though. As for a 134a conversion, the european union's trying to phase that out too, so who knows what our cars will be using in a couple years. Seems they're battling over a couple different replacements right now. Problem is, many of these refrigerants are actually blends of different types, that tend to boil off at different temperatures when a leak occurs. What this means, is who knows what part of the blend's really left in the system. New home system A/C 410a's like this, and runs at at higher pressures, making equipment more expensive to manufacture. Out going R-22, doesn't have much chlorine, and as mentioned earlier, really just a politcal thing now.

 

The internet has done a great job of perpetuating a lot of misleading info and marketing hype concerning these r12 conversions.

You can compare it to rebuilding the engine in mom's station wagon with all high horsepower parts and then sticking with the original 2v carb. Will it run, yes, will it run to potential, no.

You can get a C3 to cool just as well with 134a as r12.
There is nothing at all wrong with the sizing of the C3 system. Sizing is based on the btu of the evaporator and it is more than enough, virtually the same size as that of Cadillac Fleetwood of that era. In addition it's an alum stacked plate design, the most efficient there is.
This isn't residential or commercial cooling designed for a stable environment. Mobil systems vary greatly in requirements. My interior in S Florida will be a LOT hotter than an interior in Michigan even though the ambients are both 90°.

The boiling point of 134a isn't the same as r12, so the system has to be set accordingly. Set it so the evaporator will be as close to 32° as possible, nothing more complicated than that.

The biggest key is that 134a does require a more efficient condenser, few people install a parallel flow and the system won't work properly.
All a/c systems require as much condenser air flow as possible.

A few years ago, it was cost efficient to convert, in the last couple of years r12 is drastically reduced in price, so it can be cost effective to keep it over a PROPER conversion. One downside for people hiring it out, is that at least around here, most a/c shops no longer have the r12 equipment.

Without writing a book about it.
If changing to 134a, imperative to change the condenser.
On all systems, take out the evaporator, and clean 30 years of debris out of it and the housing.
Replace the hood seals and radiator seals.
Eliminate or repair fresh air door.

BTW, all refrigerants are flammable under pressure, but I've never heard of a problem because of it.

 

In my mind, if you need to change the condenser, the original system isn't/wasn't designed or "sized" for R-134a.
I do agree that the Harrison evaporators are perhaps the best ever manufactured.

In addition to the above, for a proper conversion, you need to also do the following:
Replace any R-12 rated hoses with 'Barrier' style hoses (R-134a will leak through R-12 designed hoses due to it having smaller molecules).
Replace all Neoprene o-rings.
Replace accumulator or receiver-dryer if so equipped (replaced on principle).
Flush system and replace R-12 oil with R-134a oil (in lines, compressor, evaporator etc).
Optional : Replace compressor for one designed to run R-134a
If your current compressor is already seeping with R-12, it will REALLY leak with R-134a. Personally, I would replace the compressor regardless.

So as you can see, properly converting an R-12 system with R-134a is not as simple as some people would have you believe.
I would rather pay for the price of R-12 than replacing the lion's share of my existing system to run R-134a (hence my original comment to replace the entire system with something like a Vintage Air system- It takes up a LOT less room under the hood, was designed for R-134a and will work. You will also have all new components designed to work together).

Just my .02, your mileage may vary.
Elm

 

I was under the assumption that you couldn't find the original R12 at a garage these days. I may end up just doing that if they can do it. Thanks for all the info guys!

 

That's exactly the way I look at it. But... I've always strayed from the pack. So don't listen to me.