A see-through plastic reservoir connects to the radiator with a vent hose. The coolant recovery reservoir and the windshield washer bottle serve as one assembly.

During vehicle use, the coolant heats and expands. The portion of the fluid displaced by this expansion flows from the radiator into the coolant recovery reservoir.

When the vehicle is stopped, and the coolant cools and contracts, vacuum returns the displaced coolant back into the radiator. This keeps the desired level of coolant in the radiator at all times, resulting in increased cooling efficiency.

Maintain the coolant level between the HOT and COLD marks on the recovery reservoir. These marks are about one liter (one quart) apart.