The Matco Tools Cooling System Pressure Tester, Refiller, and Retainer, No. MPT333, is designed to create pressure to pressure-test a cooling system. The tool allows the user to change a cooling system component on a vehicle, check the repair by pressure testing, and add coolant or refill the cooling system by turning valves. By turning a valve, a vacuum can be created to refill a cooling system with coolant. The tool can also create sufficient vacuum flow to retain the coolant in the cooling system while changing a component, so draining the coolant is not necessary.