[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.

[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