What kind of freon does a 1997 Chevy suburban use?

A 1997 Chevy Suburban likely used R-134a. While some older vehicles used R-12, the transition to R-134a was well underway by 1997. However, to be absolutely certain, you should check the sticker located inside the hood or on the radiator support. This sticker will specify the refrigerant used for that particular vehicle's AC system.