System for detecting malfunction of internal combustion engine radiator

摘要

A system for detecting malfunction of a radiator, more precisely a thermostat (shut-off valve) in the engine cooling system. In the system, an estimated coolant temperature CTW is calculated from the temperature condition and operating condition at engine starting. When the estimated coolant temperature CTW has reached a judge malfunction value CTWJUD but the detected coolant temperature TW has not reached a judge normal value TWJUD, the thermostat 64 is discriminated to have malfunctioned, thereby enabling to detect malfunction of the radiator with high accuracy and high response.