Where is the thermostat located on a 2004 Mazda 3?

On a 2004 Mazda 3, the thermostat is located in the engine compartment, specifically at the junction of the upper radiator hose and the engine block. To access it, you 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 to avoid burns.