Where is the thermostat on Ford F-250 Power troke diesel engine?

There isn't a thermostat in the traditional sense, like a single, easily accessible device you can replace yourself, located in a single, easily identifiable spot on a Ford F-250 Power Stroke diesel engine. The engine's cooling system uses a thermostatically controlled water pump. This means the temperature regulation is integrated into the water pump itself. You can't simply swap out a "thermostat." If there's a cooling issue, you'd likely need to replace the entire water pump assembly.