Schematic diagram of cooling system 1 2 3 4 5 6 1 7 8 9 12 11 10 1 Overflow and vent pipe 7 Filler pipe 2 Positive pressure / negative pressure valve 8 Thermostat 3 Coolant level in surge tank 9 Engine / crankcase 4 Surge tank 10 Water pump 5 Coolant filler neck 11 Fan 6 Degassing system 12 Radiator / intercooler 22