Engine Coolant Recovery Reservoir Discoloration Due to Engine Cooling System Sealer

The purpose of this bulletin is to provide information concerning the appearance of engine cooling system sealer when added to the engine cooling system. Some Saturn customers may comment on a brown substance that is visible in the engine coolant recovery reservoir. This brown substance may mislead a customer or retail technician to suspect that the engine coolant is contaminated with engine oil.

Engine cooling system sealer in pellet form and brown in color may not dissolve completely, leaving a residue on the inside surfaces of both engine coolant recovery reservoir and the coolant recovery reservoir cap.

Engine cooling system sealer residue can be easily distinguished from engine oil contamination by inspecting the engine coolant recovery reservoir and the coolant recovery reservoir cap. Engine cooling system sealer residue will be gritty to the touch with visible fibers.

Engine oil contamination will cause the engine coolant to be milky brown in color and will coat the engine coolant recovery reservoir and coolant recovery reservoir cap with a slick oily film. Engine oil contamination will also reduce the cooling systems ability to properly maintain operating temperatures.