R134A - you can buy over-the-counter kits for the do-it-yourself'ers, but i don't recommend it unless you have a vacuum pump and at least a gauge set. A/C systems have both high and low pressure cut-out switches, so unless you have the correct amount of refrigerant, they will not function.
Disposable refrigerant containers are only used for virgin refrigerant.
coralicigal
Your condensor outside , where the compressor is . should have an information plate showing the type of refrigerant used
ac delco spark plugs are type that originally came with 2003 GMC envoy
R 134 a
r134
R134a
r-134a
134a
R134a
R134a
R134a