Engine cooling apparatus

An engine cooling apparatus includes a main cooling water passage (14) in which a cooling water is circulated from an outlet of and to an inlet of a water jacket in an engine (10) to cool the engine. A water pump (12) supplies the cooling water to the engine through the main cooling water passage. A heater passage (28) interconnects a heater core (30) and the main cooling water passage to circulate the cooling water. A throttle body passage (32) interconnects a throttle body (34) and the main cooling water passage to circulate the cooling water. A water valve (26) opens the heater passage when an operation starting requirement of a heater of a vehicle compartment is met, which allows the cooling water from the main cooling water passage to flow into the heater core through the heater passage. In this apparatus, the throttle body passage (32) is connected to the heater passage (28) in such a manner that the cooling water from the main cooling water passage (14) is supplied to the throttle body (34) through the throttle body passage only when the heater passage is opened by the water valve (26).