Radiator cooling fan: device and possible malfunctions

The design of any modern car consists of a variety of different units and mechanisms. One such is the engine cooling system. Without it, the motor would tolerate constant overheating, which would eventually disable it. An important component of this system is the radiator cooling fan. What is this detail, how is it arranged and for what purpose? The answer to this question is further in our article.

Characteristic

The radiator cooling fan is a part that provides forced air circulation for the engine. Due to the uniform and constant removal of heat from its elements, the temperature of the internal combustion engine always remains within the working temperature and rarely exceeds +95 degrees Celsius.

Varieties

In total there are two types of constructions of these elements:

1. Electrical.
2. Mechanical.

The last kind works due to V-belt transmission of forces from the crankshaft pulley. As for the electric, the radiator cooling fan is driven by a special motor. Also, this design assumes the existence of a separate control system. The intensity of this element is directly dependent on the temperature sensor.

The device and the principle of operation

At the moment, it is common to distinguish three types of fans:

• With viskomufta.
• With thermal switch.
• With the computer (electronic control unit).

With regard to the first type, viscous-based systems are now almost never found on cars. In general, they were installed on machines with longitudinal engine arrangement or on massive all-wheel drive off-road vehicles, which also overcame water obstacles. Viscous coupling, responsible for the rotation of the fan, is completely sealed. This design allows you to protect it from the effects of external factors, including water. By the way, electric fans after penetration into the block of liquid immediately fail. Further repairs and recovery, they are no longer subject.

Viscous coupling is filled with silicone oil. The latter under the influence of high temperature changes its properties and, depending on the level of heating, increases or decreases the intensity of the fan rotation. The design of viscous coupling requires the presence of such parts as a package of drives of the driven and driving shafts, as well as a sealed housing with a gel or oil.

How does it all work? The principle of operation of this element is based on the transfer of rotational movements from the drive shaft due to disk packs. The latter are placed in a silicone fluid, that is, in a gel or oil. The viscosity of these components, as we said earlier, varies with temperature.

Elements with electric drive

As for fans with electric drive, they consist of the following elements:

• The electric motor.
• The electronic control unit.
• The temperature sensor.
• The relay of inclusion of the fan.

More modern units have in their design two temperature sensors, one of which is installed in the branch pipe, leaving the radiator, and the second - in the body of the thermostat. Sometimes it is mounted in a branch pipe that comes out of the engine. The electronic unit, depending on the difference in the readings of these two sensors, controls the intensity of the rotation of the impeller. And it is powered by an electric motor cooling fan radiator.

For correct operation of this motor it is also important to have an air flow meter and a device that will monitor the frequency of the crankshaft (DPCV). After the control unit has received a short signal from all the sensors, information is processed and the electronics activates the relay that turns on the fan. During its operation, the system controls the number of rotations and can increase or decrease the speed of the impeller. A similar design is used now on most cars and SUVs.

Devices with thermoswitch

Before the birth of systems with electronic control, all machines were equipped with fans with a thermal switch. It was this element that performed the function of turning off and on the impeller motor.

The principle of operation of such a system is as follows. From the temperature sensor, which is installed in the engine block, a signal is sent to the scale that is in the passenger compartment. Further, depending on the received indications and the degree of reaction of the liquid in the radiator for thermal changes, the fan turns on or off.

As soon as the cooler temperature increases to a certain value, the contacts connected to the power circuit by the impeller close the thermoswitch. Further, the electric current is fed to the motor, so that the fan starts to rotate. After the temperature of the antifreeze falls again, the contact opens and, accordingly, the impeller stops working.

How to find the cause of the failure of the element?

As we said in the introduction, a fan failure can cause frequent overheating of the power plant. Therefore, the driver must regularly monitor its performance and in the event of a breakage immediately eliminate it.

How to check this part for serviceability? First, remove the plug from the temperature sensor. If this element is single, you should also check its serviceability. It is not difficult to do this - it is quite simple to manually lock the terminals in the plug with a small piece of wire. If the temperature sensor is double, then to check it it is necessary to close first the white-red, and then the red wire. Ideally, after this, the radiator cooling fan should slowly turn.

Then you need to close the red and black wires. In this case, the impeller must rotate as fast as possible.

But what if the radiator cooling fan does not turn on even after several attempts of closing? Conclusion - the temperature sensor has come into malfunction or fuses have burnt. The latter are checked as follows. In the fan connector on the white-red or black-red wire is supplied current from the battery terminal with a positive charge. At the same time, a brown wire is fed from the negative terminal of the battery. If the radiator fan of the cooling system does not work after these manipulations, then it's time to replace the impeller itself. In another case, it is recommended to inspect all connectors and plugs that go from the temperature sensor to it.

What should I do if the radiator cooling fan does not turn off?

In the event that the node is immediately put into operation at startup and never turns off (and this should not be), this indicates a breakdown of the node switch sensor. How to check this item for serviceability? To do this, turn on the ignition and remove the tip of the wire from the sensor. After this, the fan should turn off. In the event that the impeller still continues to work, the sensor should be replaced. It should also be remembered that with similar symptoms, the radiator cooling fan motor is in an absolutely working condition, and it is not practical to check it in this case. But it can also happen that oxidized terminals are the source of the malfunction. When diagnosing them, you should also inspect them and, if necessary, clean the contacts.

Is it possible to repair the fan?

In some cases, there is no point in completely changing the part to a new one, since the malfunction may be completely insignificant. It will be much cheaper to repair it yourself.

Before removing the part from the fasteners, it is recommended to disconnect the battery negative terminal and remove all wires that go to the fan. Then it is necessary to unscrew the fastening elements of the device and take it out.

In some cases it happens that the originator of faults is banal dirt. Therefore, after successful dismantling, the fan blades are thoroughly cleaned of dust and other deposits. It is best to do this with a brush.

In addition, the failure may be due to poor contact of the wires. This phenomenon occurs due to the oxidation of the elements in the connecting plugs. Further it is necessary to check the efficiency of the winding of the rotor. Sometimes the radiator cooling fan does not work due to the closure or breakage of this part of the system. In this case, each turn must be inspected.

However, there are elements in the design of this node that can not be restored. In addition to temperature sensors, the electric motor of the radiator cooling fan is not subject to repair. What does it say about its malfunction? Determine the inoperative state of the electric motor is possible by the state of the impeller. If during the overheating of the power plant it does not turn on, the engine of the cooling fan of the radiator has most likely become unusable. In this case, it is necessary to replace it immediately.

Other malfunctions

All motorists know that the radiator cooling fan (VAZ 2110-2112 can be cited as an example) is a source of increased noise and vibrations. But if this sound of his work exceeds the marginal rate, so much so that the engine itself is not heard, this indicates a number of malfunctions. So, why is the cooling fan of the VAZ radiator fan noise? There may be several reasons:

1. Unscrewed bolt, fastening the impeller to the pulley (fasten the part).
2. The broken part of the blade (replace the fan).
3. Lack of lubrication on the motor.
4. Broken bearing (only replacement here).

Conclusion

So, we found out why the radiator cooling fan does not work , and also examined the ways of its diagnostics and repair. As you can see, this site is of great importance for the car. Its failure will certainly make itself felt in the form of regular overheating of the engine. And after all, after the first such malfunction, the risk of failure of the parts of the cylinder-piston group increases at times. Therefore, do not postpone this problem for later.