Stock NAS Defender 110's thermostat gates is set to 82°C/180°F.

The thermostat in in your Defender 110 provides a variety of engine and cooling system functions, functions. the thermostat links the engine and radiator, is located at the upper radiator hose where the radiator connects to the engine block. Thermostats are designed with a small internal plunger mechanism that controls coolant flow into and out of the engine. A working thermostat prevents the engine from overheating and underheating.

The thermostat simply put is a heat-sensitive valve designed to react to changing engine coolant temperatures. The defender's thermostat is designed to open at pre-set engine coolant temperature of 180 degrees Fahrenheit.

Overheating: The thermostat prevents overheating by opening and allowing heated engine coolant to flow into the radiator, and recycled coolant to flow back to the engine at lower temperatures, reducing engine operating temperature.

Underheating: The thermostat prevents underheating or otherwise prevents the engine from staying too cold by closing and locking engine coolant inside a vehicle's engine, which expedites engine warm-up.

OEM and after market replacement thermostats may be ordered from a variety of vendors.