Where is the thermostat 2003 Chevy Express van?

In a 2003 Chevy Express van, the thermostat is located in the engine compartment, specifically at the engine's front where the upper radiator hose connects to the engine block. To access it, you'll typically need to remove the upper radiator hose and the thermostat housing. It's important to ensure the engine is cool before attempting to replace or inspect the thermostat.