Is there a problem when the diesel engine high coolant temp light comes on after the engine is stopped and then restarted?
This condition is what we refer to as “heat soak”. When an engine is shut off at normal operating temperature, the coolant will continue to absorb heat from the cylinder block and head. Since there is no coolant flow through the heat exchanger, coolant temperature will rise, potentially to the point of closing the high coolant temperature alarm switch. It is not a problem.
