Description Water Pump Housing used in the OM603 water pump upgrade. The parts below are required to complete the upgrade:: Water Pump - OM606 Water Drain Pipe - OM603/OM606 Thermostat - OM603/OM606 - 80 Degree Thermostat Cap - OM606 Water Pump Housing Gasket - OM606 Water Pump Pulley - OM606