EXPANSION TANK CAP; Explorer. 10 Lbs. 16 Lbs. A cover that prevents foreign debris from entering the container. Engine Cooling. From 08/18/2008. From 12/18/2006. Location-Reservoir. Radiator Cap. Supercharger Cooling. To 08/18/2008. To 12/18/06. with Pressure Relief. Engine Coolant.