A liquid thermal management purging system for efficiently removing the liquid coolant within a liquid thermal management system prior to opening the system for maintenance. The liquid thermal management purging system generally includes a reservoir storing a volume of liquid coolant and a volume of displacement liquid and a thermal management unit in fluid communication with the reservoir. A displacement pump and a drain pump are fluidly connected between the reservoir and the thermal management unit to selectively provide displacement liquid to and remove liquid coolant from the thermal management unit (and vice-versa).