Overheating of a diesel engine can be caused by anything that decreases the efficiency of the cooling system. Low levels or loss of coolant, poor air flow through the radiator and a defective thermostat are just a few of the problems that could cause a diesel engine to overheat.
According to Arrowhead Radiator Service, a slipping fan clutch, a broken cooling fan and a collapsed radiator hose also decrease the cooling system's ability to absorb, transport and dissipate heat through the engine. The hot metal of an engine must always have contact with a cooling liquid to avoid overheating. To keep the temperature from rising, the coolant, a cooling liquid, must always be kept in circulation. The coolant must get rid of this heat as it passes through the block and head, which requires a functioning radiator. The thermostat is another important engine structure that regulates the temperature of the engine. The thermostat must always have the ability to open, or the flow of coolant comes to a halt. If the flow of coolant is ever disrupted or blocked, the diesel engine rises in temperature and overheats. It is also important to check for leaks to prevent any loss of coolant.