Partial-Load Phase
WARNING: This page is about a different car, the 2012 Dodge Charger. However, it is still accessible from the selected car via links, so may be relevant.
The main valve begins to open at a coolant temperature of 86° C (189° F), and a small amount of coolant flows through the radiator. As the engine temperature increases, the main valve opens further and the bypass valve gradually closes. More coolant flows through the radiator and less coolant flows through the bypass passage.