Sierra International 18-3251 Water Pump Kit The Sierra 18-3251 Water Pump Kit contains the following: (1) 18-0416 Wear Plate Gasket, (1) 18-3017 Impeller. Each Sierra product meets or exceeds the original equipment part it replaces. Sierra Water Pump Kit Contains the following: (1) 18-0416 Wear Plate Gasket, (1) 18-3017 Impeller Sierra part number: 18-3251