Where is the orfice tube located for a 1998 Chevy Express van?

The orifice tube on a 1998 Chevy Express van's A/C system is located within the receiver/dryer. Unlike some systems where it's a separate component, on this vehicle the orifice tube is integrated inside the receiver/dryer canister. Therefore, you won't find it as a stand-alone part. To replace it, you'll need to replace the entire receiver/dryer unit. The receiver/dryer itself is usually found near the firewall on the passenger side, but the exact location might vary slightly depending on the specific engine and A/C configuration.