GM-33984-A Cooling System Pressure Tester Adapters are used with GM-47716 to connect to the radiator to evacuate and refill the vehicle cooling system. This tool greatly increases the coolant fill efficiency on all cooling systems. This tool works extremely well on cooling systems prone to airlock. The tool duplicates the fill process used in the assembly plants and allows technicians to pull multiple deep vacuums on the entire cooling system. The technician can pull a deep vacuum to find and correct coolant leaks before filling and thermocycling the system. GM-47716 also allows the technician to remove coolant from a system using an included pipe to pull coolant into the tool drain reservoir.