For 1990-2009 cars

#### Coolant Recovery Reservoir

A plastic coolant recovery reservoir connects to the radiator with a hose. As the vehicle is driven, the engine coolant heats and expands. The portion of the engine coolant, displaced by this expansion, flows from the radiator into the reservoir. When the engine is stopped, and the coolant cools and contracts, vacuum draws the displaced coolant back into the radiator. Thus, the radiator is kept filled with engine coolant to the desired level at all times, resulting in increased cooling efficiency.