A service hose, with the proper adapter attached, is inserted in place of the radiator cap. By using the “suction” side of the air pump to pull a vacuum in the machine’s selected storage tube, and at the same time “pulling” a vacuum in the engine’s cooling system, the coolant is removed. In most cases, this is done without disconnecting any radiator hoses. To start the coolant exchange, the machine’s tube control valves are pointed to the tube number that will be used to store the old coolant (usually tube 1—the hot tube). The master control switch is then pointed to “vacuum”.

As the liquid in the engine’s coolant system begins to warm-up, the vacuum generated by the pump will lower the boiling point of the liquid, thereby allowing it to be drawn into the tube. By observing the flow of liquid in the transparent service hose, the technician can determine when all of the available liquid has been drawn from the coolant system.

To install new coolant, the vacuum “pulled” on the engine’s coolant system is used to draw the new coolant into the radiator via the service hose. Turn the tube control valves to “Tube 2” and the master control to the black dot, or press the button on top of the tube cap. New coolant is drawn into the coolant system and will stop flowing when the system is full.

The Coolant Rx machine typically pulls 20 inches of vacuum on a leak free coolant system. If the system has a leak, a less than normal vacuum reading will show on the vacuum pressure gauge mounted on the control panel.