摘要 |
Disclosed is an engine cooling system which comprises: a head-side circulation pathway through which coolant from a water pump is circulated via a water jacket of a cylinder head and an EGR cooler; a block-side circulation pathway through which the coolant from the water pump is circulated via a water jacket of a cylinder block; and a switching valve unit operable, during cold operation of the engine, to pass the coolant from the water pump, along the head-side circulation pathway, and, when a temperature of the engine is raised up to a predetermined value, to pass the coolant from the water pump, along not only the head-side circulation pathway but also the block-side circulation pathway. |