Patent ID: 7207297

Claim:
An internal combustion engine cooling system including a flow control valve capable of controlling flow rate of cooling water flowing through a bypass passage bypassing a radiator, and a coolant temperature control means for controlling coolant temperature by controlling the flow control valve, the system comprising: a valve diagnosing means for diagnosing the flow control valve for abnormalities; a heat generation rate reducing control means that executes a heat generation rate reducing control operation to reduce heat generation rate of the internal combustion engine when the valve diagnosing means determines that the flow control valve is in an abnormal condition; and an abnormality level determining means for determining abnormality level of the flow control valve among a plurality of abnormality levels when the valve diagnosing means determines that the flow control valve is in an abnormal condition, wherein the heat generation rate reducing control means sets control parameters and/or control quantity for the heat generation rate reducing control operation according to the abnormality level determined by the valve diagnosing means.