Method for preventing engine overheat based on coolant temperature and engine system thereof

An engine system comprising:

• a first coolant temperature sensor configured to detect a coolant inlet temperature at an inlet of an engine;
• a second coolant temperature sensor configured to detect a coolant outlet temperature at an outlet of the engine;
• an integrated thermal management (ITM) valve configured to distribute a coolant to a heat exchanger associated with a radiator;
• a controller configured to:
• check that the coolant is distributed to the heat exchanger together with the radiator being switched from a closed state at a start of diagnosis to an open state during the diagnosis under the control of an opening degree of the ITM valve,
• calculate factors by temperature difference ranges as a factor cumulative value by an inlet/outlet coolant temperature difference calculated as a difference between the inlet coolant temperature and the outlet coolant temperature, and
• control the ITM valve to a full open state in case that a lack of a coolant amount is diagnosed;
• and
• an emergency control system being operated under the control of the controller and configured to delay an increase of the coolant temperature.