Patent ID: 8695552

Claim:
A temperature control system for an internal combustion engine, to which a block heater for warming a coolant and keeping the coolant warm is attachable, the temperature control system comprising: a coolant circulating apparatus configured so as to circulate the coolant; a fluid temperature detecting device configured so as to detect a fluid temperature of the coolant; a block heater disuse estimating portion implemented by a control unit and configured so as to estimate a possibility of disuse of the block heater, wherein the estimating takes place when a circulation of the coolant is stopped by the coolant circulating apparatus; and a block heater usage determining portion implemented by the control unit and configured so as to determine whether or not the block heater is used on the basis of changes in the fluid temperature detected by the fluid temperature detecting device under a condition that the coolant is circulated by the coolant circulating apparatus in a case where the block heater disuse estimating portion does not estimate the disuse of the block heater.