Jim Keef

Trying to find out just how much is a 50 pound tank of R12 that has never been used worth?

I would suggest that you don't even think about charging the cars with R12 as high as it will cost you will probably be better off to test pressure the system with air pressure first and if it don't leak pull a good vacuum and change it to 134A. But then again you are still not out of the woods, because when you have the system fully charged, there will be more pressure on the system because freon will have more pressure than air so it still may blow out. What ever you decide to do, good luck.

I am a certified licensed HVAC technician and a auto A/C licensed technician for more than 25 years. To answer your question, it depends on the auto say you had a all car it should take no more than 16 to 48 oz. But a large SUV or a van they usually have 2 units one for the front and one in the back. Now they could take as much as 4,5,6, pound's or more. Also there is a low valocity oil mixed in with the freon most cars take about 8 to 10 oz so if you loose all or some of your freon you need to put some oil back in also , and one more thing, you said the A/C units in these cars has not worked in some time, well you will probably have a 50 50 chance of the A/C units that will blow out the compressor seal's and all the o rings cracked and dryer out because like I said there is oil in the system with the freon and if your A/C units have not been used in a while to keep all the rubber that includes the rubber hose line it will dry out and when you start charging a system with freon the pressure could crack open the seal's in compressor, o rings and rubber hose line will leak out all your freon. And if that happens to the seal's in compressor there is nothing you can do except kiss it goodbye. A/C system,s must run from time to time to keep the system lubricated

I am a certified licensed HVAC technician and a auto A/C licensed technician for more than 25 years. To answer your question, it depends on the auto say you had a all car it should take no more than 16 to 48 oz. But a large SUV or a van they usually have 2 units one for the front and one in the back. Now they could take as much as 4,5,6, pound's or more. Also there is a low valocity oil mixed in with the freon most cars take about 8 to 10 oz so if you loose all or some of your freon you need to put some oil back in also , and one more thing, you said the A/C units in these cars has not worked in some time, well you will probably have a 50 50 chance of the A/C units that will blow out the compressor seal's and all the o rings cracked and dryer out because like I said there is oil in the system with the freon and if your A/C units have not been used in a while to keep all the rubber that includes the rubber hose line it will dry out and when you start charging a system with freon the pressure could crack open the seal's in compressor, o rings and rubber hose line will leak out all your freon. And if that happens to the seal's in compressor there is nothing you can do except kiss it goodbye. A/C system,s must run from time to time to keep the system lubricated