R12 AC System Options

[00 SS]

I've heard R12 systems can be converted to R134a. Does anyone know what's involved? Should I convert my old car to R134a, or should I just try to get it charged with R12? I've heard that you have replace the seals in the system, but I've also heard that you don't. If it's easy and reasonably priced, I'd probably convert it.

[roy]

Since R12 is no longer sold in Germany. I just remove the compressor and evap and get all the oil out and put in the exact amount of R134 compatible oil and charge the system with R134. It cools but is not as coldas R12, but close.

[TSHACK]

There use to be kits for this a few oring a new fill port so you can connect the
R134 hose to you system. the way I've seen this done was, to pump the system
down to remove the R12, change seals & the port. verify oil level, pump down agian. leak check then charge, with R134. fallow kit instruction. some come with an oil charge.
when dealing with freon there are laws to deal with. Just so you know.

[Mojave]

As I'm sure you know, R12 isn't produced anymore and is getting harder to find and more expensive. But, a system designed for R12 will definitely cool better with R12 than R134a. Modern systems designed around R134a cool just fine too, but it takes more R134a (and I suspect a larger evaporator) to get the same performance as R12. As stated above, the conversion is pretty straight forward.

If you can find some R12 and the price isn't stupid, it might be worth it to keep using it for the better cooling performance. It will probably be cheaper to convert it and run R134a.

[TSHACK]

I agree with mojave on the R12 if you can find it cheap. I've seen freeze12
work pretty fair too. It was cheaper by A long shot, but is getting hard to find also.

[rpoz-29]

I've converted 3 vehicles from R-12 to 134a. Two Ford pick-up trucks, and my son's Acura. A friend swore he converted his by simply replacing the R-12 with the 134a. I by-passed the limit switch so the compressor would run when I turned on the AC switch, broke the line coming from the compressor and ran it for a second. I added the prescribed amount of ester oil into the compressor, and filled it with 134a, and it worked. I didn't replace all the "O" rings, or any of that. They would leak down over the fall/winter/spring, but I just charged them back up after that. I've sold the 2 Fords, but my son still drives the Acura. In my applications, it seemed to take less 134a than R-12 to make it work. Kind of a "jack-leg" repair, but it worked okay.

[turbotoddie]

Purchase AC flush, remove the compressor and drain the oil. Flush the system with the AC flush at a low air pressure so as to not atomize the flush. You want it stay a liquid. You do not need to change any orings or other stuff. Since you have the system open, I would recommend changing the dryer and orifice. As for flushing, buy Dura brand flush as it is the best. Cheaper ones like Johnson's brand don't evaporate as well. If I was going to keep the car, I would replace the condenser as most replacements now have an upgraded tube design to work with 134a. Anyways, a clean condenser is the key to it running cold. Find the spec for the volume of oil that needs to be in the system. I don't use Ester much. As the parts store for what pag oil works with your compressor. Most GM's use pag 150. Vac system for at least an hour, shut off the vac and see if you have any leaks. Charge with 134a the same volume as R12(early suggestions recommended 75-80% but the freon is what carries the oil so you need it all). The best way to measure if the system is full is to use a contact pyrometer(not infrared) and measure the temps of the tube going in and coming out of the evap. Once they match you are full. Try to get them within 3 degrees.

Also, if possible, charge from a large cylinder and not little cans as you can get some air in the system with the little cans.

What kind of car are we talking about? FWIW, I have bought cars to fix and sell and literally vac'd them down and charged with 134 and they were some of the coldest I ever converted. Your success depends on how good a job the condenser does.

turbotoddie

This post has been edited by turbotoddie: May 19 2009, 01:25 PM

[00 SS]

The car is an '88 Buick Park Avenue. It's just about to hit 100,000 miles so it's got alot of life left in it and it's in very good shape. I can see driving this car for a few more years.

Thanks for all the advice on how to convert to 134a. But I'm still considering whether or not to convert it. Everybody seems to say that it will cost more to leave it as R12, but looking on eBay, I can get several cans of R12 and a guage/manifold set for under $150. Can the system be converted for $150 or less? The system currently works, but it's not very cold. My guess is the system has not been charged in MANY years. This was my grandmothers car and she rarely used it.

I have no vac pump, I've seen them on eBay for about $60. An R134a guage/manifold set is about $75. 134a refrigerant is about $6/lb and I'm guessing the system would hold 10-15 lbs, so say $75. It looks like it would cost at least $200 to convert it if I need no other parts. Plus the time involved appears to be at least a full day. I know future recharges would be cheaper and maybe easier but I'm just wondering if it's worth it.

This post has been edited by 00 SS: May 19 2009, 05:06 PM

[turbotoddie]

If it is cool but not cold. Find someone that already owns a set of R12 gauges, should be easy and that same person can probably still buy R12 and feed him a couple of beers to charge up the system. The system itself probably holds 2 to 2.5lbs. If it is cool, it will take probably one can to get it cold, possibly two. Do not buy R12 off ebay as you don't know what you are getting. I have seen old cans that have literally leaked out the product to cans that were filled with 134a. If you are going to do it, the cheapest route is not the best!

[c4racer]

buy and horde that R12 stuff!!

Anybody know if there are issues storing it? Does it go bad over time, or can cans be stored for years w/o problem?