You should not let anyone talk you into converting from R-12. The EPA has not approved ANY drop-in replacement for R-12. The seals and "O" rings are not compatible with the lubricant used for other gases. The oil in your system cannot be entirely removed without completly flushing the system and rebuilding the compressor. Some of the advertised replacements are really blends of several gases including propane and butane. All replacements run at higher head pressures and require a larger condenser to achieve the same capacity as R-12. Even if you switch no one will be able to tell you how long the system will run before the oils destroy metal parts and seals. Even though R-12 is going for about $60 a pound you only need 2.5# so it is not the worst thing to stay with. The labor will cost more than that no matter what you put in. Make sure that the system is THOURGHLY leak checked so it isn't wasted. Most good shops use an inert dry gas (like argon or nitrogen, or even instrument air) to test the system and sweep out any contaminates in preparation for the Freon. A good shop will also want to replace the dryer if the system has been open to the atmosphere. If you do change to a substitute make sure that the service valves are changed and the system is properly labled so no one will mistakenly put R-12 in again. David Teitelbaum vin 10757 [moderator snip]