Cooling system for diesel exhaust fluid doser

A method of operating a cooling system connected to a diesel engine and an exhaust system of the diesel engine, the method comprising:

• energizing a pump in a first mode of operation to circulate coolant through the diesel engine and through a coolant channel situated around a diesel exhaust fluid doser;
• discharging coolant from the coolant channel upwardly into a coolant reservoir in the first mode of operation;
• transitioning to a second mode of operation in which the pump is not energized;
• directing vaporized coolant from the coolant channel through the coolant reservoir and then through a vent line to a coolant surge tank in the second mode of operation;
• and
• continuously back-filling the coolant channel with a gravity-fed supply of liquid coolant from the coolant reservoir as coolant is vaporized in the second mode of operation.