I have just been checking on getting some R12 added to my system as I believe I am a bit low. My first call was to a friend of mine who works at a Chrysler dealer and has R12. It is $55 a pound for the R12, one hour labor, a $57 EPA fee, for a total of $200-300. I called my body man and asked if he knew of someone reputable to add some R12, and he directed me to a friend of his in the service business, who uses "FrostFree" which costs $15 a pound and $30 labor. He says the FrostFree is %100 compatable with R12 and is a direct environmentally safe product which involves no system upgrade and blows cold like R12. He says he does R134 upgrades but feels the FrostFree is the way to go for older cars. The point here is "buyer beware". All of this scare about R12 is unwarranted. By talking to this guy and some web research it appears that there are now a number of fully compatable direct replacements for R12 without system upgrade. This may explain why Wal-Mart and everyone else is now selling $40 R134 conversion kits. It you want to stay with R12, stay with it!

 

If your friend is A/C certified, have him call Advance or Pep Boys and get you a can of R12. It's about $35 here. You can probabaly buy an A/C manifold in a pawn shop for $15-20 and do it youself.

You can use that other stuff, but it will be harder to maintain system balance due to different size molecules.

 

I would not do any of the "replacements". They are all blends, which have their own set of problems. First of all, once you add anything but R12 or R134a no shop will touch your car. Reason is simple: To work on it they have to evacuate your system. They have a tank for R12 and one for R134a. Anything different contaminates their tank and it will cost them a sizeable chunk to dispose of it.

Next the blend itself is a problem. Since you are low you have a leak. The lighter gasses in the blend will leak faster than the heavier gasses. You then end up with an unknown blend in the system to where it will not work right without replacing all of it. You're now back to point 1: no one will touch it.

I converted my '71 to R134a and love it. Blows low 40's out the vents. I haven't touched the system in over 2 years. No leaks.

 

It cost me about $450 to convert to 134a after parts and tools and such.
If my compressor had been good I would have had the r12 serviced by a shop. Two or three hundred isn't that much when you consider it should last for 5 to 10 years after they fix the leaks.

 

This is officially known as R12A, and is certified to blend or use with R12 as the substitute. It is not R134A or the like. R134A is a replacement. A check on the net shows a few different companies now making R12A. All of the fittings are identical and its chemical properties mirror R12. As for a leak I agree, but over the years I have seen many AC systems lose a slight amount of fluid over time and need a little boost every now and then. My approach will be to check all fittings and add some dye on the charge to see if there is any major leakage. I do not believe I have lost much freon as it is blowing fairly cold, but the compressor is cycling a little too often, which all agree means it is a lttle low. Of all fo the mechanics I have talked to none seem to think this is a major issue.............My car sits during the winter and is only started periodically, and it seems that by the end of winter I get a trans drip, and and oil drip. Once I start driving it this drips go away. Most all agree that the seals tend to dry out a bit from non-use and by using the seals re moisten and do their job. I beleive this may be the same situation. I have owned the car 3 years and the AC has worked fine. It cools now, just not at the level expected, so going this route seem safe and prudent by what I have read. The shop I am dealing is supposed to be a reputable shop dealing in classics...... From what I ahve read the R134A conversion seems much more suspect, and I have read quite a few comments regarding compressor siezure after switching.