GM Service Manual Online
For 1990-2009 cars only

Object Number: 185612  Size: SH

Important: When aligning the coolant recovery reservoir cap (1), align the arrow marks on the reservoir (2) and the cap.

A see-through plastic coolant recovery reservoir, similar to the windshield washer fluid reservoir, is connected to the radiator with a hose. As the car is driven, the coolant is heated and expands. Fluid displaced by this expansion flows from the radiator into the coolant recovery reservoir. When the car is stopped and the coolant cools and contracts, the displaced coolant is drawn back into the radiator by a vacuum. Consequently, the radiator is filled with coolant to the desired level at all times, resulting in increased cooling efficiency. At normal engine operating temperature, the Engine Coolant Level (ECL) should be maintained between the FULL and LOW marks on the coolant recovery reservoir.