How do you replace the thermostat of Corsa 1.4?

To replace the thermostat on a Corsa 1.4, first ensure the engine is cool and disconnect the battery. Remove the coolant reservoir and drain the coolant from the system. Locate the thermostat housing, typically near the engine block, and unbolt it to access the thermostat. Replace the old thermostat with a new one, ensuring the rubber O-ring is properly seated, reassemble the housing, and refill the coolant before reconnecting the battery.