Description 80 degree thermostat used in the OM603/OM606 engines, also in the OM 603 water pump upgrade. The parts below are required to complete the upgrade:: Water Pump - OM606 Water Drain Pipe - OM603/OM606 Water Pump Housing - OM606 Thermostat Cap - OM606 Water Pump Housing Gasket - OM606 Water Pump Pulley - OM606