Coolant Recovery System

WARNING: This page is about a different car, the 2002 Pontiac Montana, 2002 Oldsmobile Silhouette, and 2002 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.

The coolant recovery system consists of a plastic coolant recovery reservoir and overflow tube. The recovery reservoir is also called a recovery tank or expansion tank. This tank is partially filled with coolant and is connected to the radiator fill neck by the overflow tube. Coolant can flow back and forth between the radiator and the reservoir.

A cooling system with a coolant recovery reservoir is a closed system. When the pressure in the cooling system gets too high, the pressure will open the valve in the pressure cap. This allows the expanded coolant to flow through the overflow tube and into the recovery reservoir. As the engine cools, the temperature of the coolant drops and a vacuum is created in the cooling system. This vacuum opens the vacuum valve in the pressure cap, allowing some of the coolant in the reservoir to be siphoned back into the radiator. Under normal operating conditions, no coolant is lost. Although the coolant level in the recovery reservoir fluctuates, the radiator and cooling system are kept full. A coolant recovery reservoir eliminates almost all air bubbles from the cooling system. Coolant without bubbles absorbs heat much better than coolant with bubbles.