TM 9-2320-209-10-1 b. Arctic Winterization Kit Controls and Indicators -Cont. 1. Inlet coolant shutoff cock. Is 2. Outlet coolant shutoff cock. Is opened (turned left) to let coolant opened (turned left) to let coolant from power plant cooling system from heating chamber of power enter heating chamber of power plant heater enter power plant plant heater. cooling system. 4-26