Engine Cooling - System Operation And Component Description (G1550497): Thermostat
WARNING: This page is about a different car, the 2015 Jaguar XF, 2014 Jaguar XF, and 2013 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.
The thermostat is closed at temperatures below approximately 82°C (179°F). When the coolant temperature reaches approximately 82-90° C (180-194°F) the thermostat starts to open and continues to open to the fully open position as the engine operating temperature increases. In the fully open condition the full flow of coolant is directed through the radiator.