Schematic representation of a water pump (centrifugal pump): 1 - pump body; 2 - pump wheel (centrifugal wheel); 3 - drive shaft; 4 - gasket; 5 - drive wheel (belt pulley).
Radiator: consists of synthetic water-collecting boxes on each side. Both boxes are connected to each other by a multitude of thin-walled tubes. In order to increase the radiator surface many times, there are accordion-folded plates between the tubes: they remove excess heat directly into the oncoming air flow. The Focus radiator is fixed to the upper and lower crossbars.
Thermostat: maintains a constant coolant temperature. New thermostats, depending on the engine model, open at 85-90°C and open fully at 99-102°C. In used thermostats, the tolerance is ±3°C. Thermostats consist of a closed, special wax-filled thermoelement (cylinder), a pressure spring and a valve plate. To the extent that the liquid in the engine heats up, the wax expands in the thermoelement and lifts the valve plate in its seat, overcoming the resistance of the pressure spring. The valve is fully open only at operating temperature. If the liquid cools down, the spring presses on the valve plate and accordingly blocks the flow.
Expansion tank: automatically replenishes the amount of coolant circulating in the cooling system. Excessive pressure in the system is released through the high-pressure valve in the shut-off cap of the tank, the low pressure is equalized by the second valve in the shut-off cap. The transparent plastic tank is located on the right in the direction of travel in the engine compartment.
Radiator Fan: all Focus engines have an electrically driven fan. The fan is often referred to as a cooling fan.
[The original article is posted at: FORDBOOK.ru]