Engine cooling system device

It is clearly visible: the coolant level in the transparent compensation tank next to the right suspension strut.

If you often add small volumes of water, then check the system for leaks and add antifreeze closer to autumn.

Under normal operating conditions, the Mondeo cooling system is always present, i.e. in «healthy» temperature range. «Cooling» is a union of several units: a heat exchanger (radiator), water pump, cooling fan, thermostat, expansion tank, coolant pipes and hoses are only «extras» for the coolant that does its job in the cylinder block and cylinder head «under constant pressure» in a filigree network of strictly proportional water channels, the so-called «water jacket». The excess thermal energy stored in the water jacket from combustion is removed by the heat exchanger to the atmosphere. Which secret paths the coolant circulates in the Mondeo depends, of course, on the temperature of the engine and the current conditions of use.

With a cold engine - a small circle of coolant circulation

After each start of a cold engine, the coolant first pulsates in a small circle, it is limited «water jacket» and heater core. During this phase, the electrically powered thermostat in the new Mondeo delays flow to the radiator until the engine has reached its operating temperature.

This is an important reason. Since the circulating volume of liquid in the small circulation circuit is smaller, the engine thus reaches the desired temperature earlier and emits less exhaust gas. As soon as the coolant has reached its operating temperature, the thermostat opens and the heated coolant flows in a dosed manner from top to bottom through the heat exchanger. On this way through her radiator «blows» headwind passing by the radiator segments and taking away excess heat energy.



Thermostat-coordinated interaction of elements «air and water» protects the engine from both cold shock and hot collapse.

When the engine is warm - a large circle of circulation of the coolant

At normal operating temperature, coolant in the Mondeo runs from the right side radiator reservoir (relative to the direction of travel) to the water pump. From there, it enters the cylinder block and cylinder head of the engine: through the open thermostat, the main part of the liquid flows back into the left radiator tank, the rest does so far «detour» through a heat exchanger. The liquid flowing from below in the radiator automatically creates a place for the inflowing heated liquid from above - the liquid circuit is closed. If the coolant temperature drops below the set operating temperature while driving, the thermostat closes until it warms up again.

«The economy of the circulation system»: components of the engine cooling system in the hydraulic «contact»

1 - Heat exchanger - heating, 2 - Engine, 3 - Thermostat, 4 - Water pump, 5 - Cooling fan, 6 - Coolant compensation tank.

Constantly pressurized - cooling system

When the engine is running, the cooling system is constantly under a certain excess pressure. This raises the boiling point of the coolant from 100°C to about 120°C. High engine temperatures reduce fuel consumption and exhaust gas emissions. If, with a hot engine, the pressure in the cooling system - depending on the engine version - exceeds 0.85 - 1.2 bar, then the pressure reducing valve on the sealing cap of the expansion tank closes and the excess pressure in the cooling system vents to the atmosphere. The resulting vacuum in the system immediately balances the valve in the locking cap. As soon as it opens, outside air enters the tank and pressure equalization occurs. Particularly when traveling in the city or when driving in the «Stop-and-go» often headwind is possible «not meet», and the engine must be sufficiently cooled and protected from defects caused by overheating. For this special occasion, all Mondeos have an electrically driven fan directly behind the radiator. This small wind power unit activates a thermal switch at around 120°C. the fan automatically switches off again when the normal operating temperature is reached.

Reduce pressure: The cooling system is checked using a mechanical pump. 2 To do this, the pressure in the radiator or receiver is reduced by approx. 1.6 bar for approx. 5 minutes. The system pressure must drop by about 0.2 bar, otherwise the leak must be looked for and repaired. 1 Compensation tank sealing cap.

Continuous monitoring of engine temperature

If the engine temperature is constantly exceeded during maximum load, for example, driving with a trailer, or due to other malfunctions, then the Mondeo engine installed in the drive control unit will protect against major engine damage (RSM) overheating program. At stage 1, the program instructs only the pointer of the temperature indicator to settle in the red range of the scale.



If you ignore this signal and the temperature continues to rise, the warning light on the instrument panel lights up «drive failure». In this case, be sure to let the engine rest a bit, it should cool down and then you need to go to the Ford station. During this intermediate period, the control unit does not work, however, it has recorded a fault code that can be read at the station by the diagnostic program. If, nevertheless, the indication of the indicator and the lighting of the signal light are ignored, or you accidentally do not notice, the 2nd stage of the program comes into effect: the PCM deactivates two cylinders and limits the engine speed. At the same time, the indicator on the dashboard will now warn before further engine damage.

In order to release the engine in this critical phase, both «dead» cylinder at this time suck in clean air. In order to lower the temperature level as evenly as possible, the cylinders alternately «rest». If you ignored stage 2, then stage 3 leaves you exactly 30 seconds of time to stop your «hot» Mondeo on the side of the road. And to avoid major engine trouble, the PCM system then simply shuts off the engine.

TECHNICAL DICTIONARY

Parts of the cooling system Basic design of the cooling system: 1 - Plate radiator with side water tanks, 2 - Internal air guide with fan flange, 3 - Electric additional fan, 4 — Connecting plug, 5 - Electric radiator fan, 6 - Connecting plug, 7 - Compensation tank of coolant, 8 - Stopper of the tank with a pressure reducing valve, 9 - Lower coolant hose, 10 - Connecting plug, 11 - Thermal switch, 12 - Upper coolant hose. Customize coolant: water pump (centrifugal pump). 1 - Pump housing directly in the cylinder block, 2 - O-gasket, 3 - Water pump with pump wheel (impeller). Water pump: in all Mondeo engines, centrifugal pumps are designed to accelerate the movement of coolant in the cooling system. He takes his place in the four-cylinder Mondeo on the right front side of the engine, in the V6 on the left bank of cylinders on the side of the sixth cylinder. Radiator: consists of plastic tanks with water located on both sides. Both tanks are interconnected by means of many thin-walled aluminum tubes. Thin aluminum strips folded like an accordion are in contact with the tubes: they multiply the surface of the radiator and remove excess heat towards the headwind. The Mondeo radiator is attached to the top and bottom cross members. Thermostat: designed to regulate the temperature of the water in the engine and keep it at a constant level. Most thermostats, depending on engine version, open between 99-102°C. For already used thermostats, the tolerance is /– 3°C. Thermostats consist of one closed thermoelement filled with special wax (cylinder), clamping spring and valve disc. As the coolant heats up, the wax in the fuser expands and lifts the valve disc out of its seat against the force of the spring. Only at operating temperature is the valve fully open. When the water cools, the spring presses against the valve disc and accordingly blocks the passage of the flow. In Ford vehicles, an electrically heated thermostat now regulates engine temperature for the first time. Its operation depends on the information transmitted by the coolant sensor (EATING), intake air temperature and current load sensors (TMAR), as well as from the vehicle speed sensor (VS/OS). This «trio» is under the direct supervision of the on-board computer (RSM), which processes the signals taking into account the parametric diagrams and transmits them to the coolant regulator. The thermostat is not energized in those ranges in which the temperature level of 98°C does not cause any consequences. In all other cases, in the presence of elevated temperatures - for example, at full load - when engine defects are possible, the thermostat filler is energized and the thermostat is already «juggles» high temperature level. Within a few seconds, the access to the large coolant circuit is further increased, and the engine temperature is thereby lowered to approximately 80°C. Compensation tank: automatically replenishes the volume of circulating coolant in the cooling system. Excessive pressure in the system is reduced by a pressure reducing valve located in the tank cap. The vacuum evens out the second valve in the locking cap. The transparent plastic tank is located in the engine compartment on the right in relation to the direction of travel. Cooling fan: all Mondeo engines are equipped with an electrically driven fan. This fan is also often referred to as a radiator valve.