How to add refrigerant to a 1993 Deville?

I saw freeze 12 available locally in one parts store (has since closed down) and asked them about it, they still wanted me to prove I was EPA cert before I could buy it... My understanding was that freeze 12 still contained a fair bit of r134, but had other refrigerants mixed in that would carry the old oil from the R12 to prevent seizing the compressor. Never having used it I am not certain though. One thing you can have problems with when using a blended refrigerant like that is each refrig. leaking at a different rate which could make topping off and keeping the proper ratios impossible. Each recharge would really need to be to an empty system.

I found a product on ebay called "envirosafe" that I had pretty good luck with. It has dye in it already to help aid leaks. It cools great, but unfortunately my system is still too leaky so it only last a few weeks. My system holds a good vacuum though so finding the leak is proving to be a chore. Too not be "deceptive" be aware that envirosafe and other products made with the same mix contain flammable material, ( Not sure about the above mentioned freeze 12). Personally I have never seen or heard of anyone injuring themselves solely due to that. People say their could be a deadly "kaboom" if you got in an accident, but I dont really buy that. I would be much more worried about the 18gallons of gas blowing up then the few ounces or low pressure flammable a/c refreg. that is in a closed system. Just be aware though.

Freeze 12 will work with the old oil but you must be careful adding it. There are so many things you can screw up rather easily on an A/C system if you do not know what you are doing. I just spent an entire semester in an Automotive HVAC class and learned a lot of information. Pick up a DVD if you can, I know they sell them at Autozone and Advanced. It will not tell you everything you need to know but it will inform you on what NOT to do so you don't destroy your A/C system.

Also, once you put Freeze12 in your car you will not find a shop willing to work on it. Federal laws say that all systems have to be evacuated and the refrigerant collected before starting work. Shops remove the refrigerant and recycle it, putting it back in the car after the work is done. However, if you have anything other than R12 or R134 they will NOT remove it because it will contaminate their equipment and the other refrigerant in the cylinders. Another thing not to add is the leak stop. After you add that the entire system must be replaced if anything ever goes wrong because that shit clogs up everything. I highly recommend having a shop convert it to 134.