What type of refrigerant does a 1998 Chevy silverado z 71 take?

A 1998 Chevy Silverado Z71's AC system likely used R-134a refrigerant. While R-12 was used in older vehicles, R-134a became the standard in the mid-90s. It's best to confirm this by checking your vehicle's owner's manual or a sticker on the underside of the hood. However, R-134a is the highly probable answer for that year.