What must be done to convert R-12 to R-134 on a 1989 Grand Marquis?

Answer 1

My first impulse is to say: Take it to a qualified and certified automobile air conditoning repair person. I know that's kind of hard to swollow, but, R-12 is very much regulated by the EPA. The existing charge must be recovered (totally removed) with specialized equipment, the system must be purged of all oil, many times major and key component parts must be replaced (due to incompatibility with R-134a), the hoses must have special attention due to density and chemical differences between the refrigerants... And the list goes on and on. What I'm saying is, it is not a job for a shade tree mechanic (* this question would not be asked if you were a qualified individual). * I know that sounds harsh, but, it's very true. Also, all of above requires specialized tools and equipment, which only a certfied mechanic would have a reason to possess. If your system is not leaking or does not have a serious mechanical problem, find someone who is certified to have Refrigerant R-12 in possession, repair the leak or whatever is wrong and have him properly reprosses the system. The main reason why is economic... Even with the high cost of the refrigerant. The next reason is that R-12 is between 15 and 20 percent more efficient than R-134a. I don't think you would be happy with R-134a in there, especially if you live in Texas or Florida. Having taught Automotive Air Conditoning at a university in Michigan, it is my recommendation that you do not consider this as a project to be done by someone other than a qualified person, for more reasons than stated above.