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How the coolant circulates

How the coolant circulates Top radiator hose Expansion tank and cap Top tank Coolant fillter plug The thermostat valve is opened by the wax inside melting. Water channels in block and head Heater blower fan Heater Hose from heater Hose to heater from block Bottom radiator hose Water pump Engine driven fan Drain tap Bottom tank Radiator core

A typical water-cooling system with an engine-driven fan: note the bypass hose taking off hot coolant for the heater. The pressure cap on the expansion tank has a spring-loaded valve which opens above a certain pressure.

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