1991 Chevy Cavalier A/C

Blue hose, engine and compressor running, leave can upright so only vapor goes in. Liquid will damage the compressor. Be sure to use the correct refrigerant. R-12 and R-134 are not compatible. If the can doesn't become empty in a minute or two, place it in a container of hot water, but always keep it upright. If the system was totally empty or was opened to outside air, it must be pumped into a vacuum for a half hour to remove any moisture from condensing humidity before adding refrigerant. Overcharging the system is more damaging than undercharging it

Wear safety glasses and a safety shield. Contact with refrigerant can freeze eyeballs and cause frost bite.

Caradiodoc