Normal operation and Fault Conditions
WARNING: This page is about a different car, the 2013 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.
The engine cooling system is a closed system providing for coolant expansion and contraction as well as changes in pressure as coolant warms and cools with engine operation. Various gaskets, seals, hoses and clamps contain coolant within the cooling system and keep other fluids and contaminants from entering the cooling system.