Cooling System Description and Operation: Thermostat
WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.
The thermostat (1) controls the flow of coolant and is mounted to the cylinder head. The thermostat contains a wax pellet (2) that expands and contracts based on the coolant temperature, which will mechanically move the main spring and a sealing disc to control the flow of coolant. The thermostat will begin to open electrically at 90°C (194°F) and will fully open mechanically at 105°C (221°F).