An overflow hose connects the see-through plastic reservoir to the neck of the radiator. During vehicle use, the engine coolant heats and expands. The displaced engine coolant, resulting from the fluid expansion, flows through the overflow hose from the radiator into the coolant recovery reservoir. After running the vehicle and shutting off the engine, the engine coolant cools and contracts. Vacuum then draws the displaced engine coolant back into the radiator. Because the system maintains the desired level of engine coolant in the radiator at all times, this results in increased cooling system efficiency.

Keep the engine coolant level between the ADD and the FULL marks on the coolant recovery reservoir. These marks are approximately one liter (one Quart) apart. Use a 50/50 mixture of DEX-COOL™ or equivalent and distilled water in order to keep the system at the FULL mark when the system is hot. Engine coolant should only be added to the coolant recovery reservoir. Refer to Cooling System Draining and Filling .