Radiator cooling fan: device and possible malfunctions

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:41

The design of any modern car consists of many different components and mechanisms. One of these is the engine cooling system. Without it, the motor would endure 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 what is it intended for? The answer to this question is later 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 internal combustion engine temperature always remains within the operating range and rarely exceeds +95 degrees Celsius.

Varieties

There are two types of structures for these elements:

1. Electric.
2. Mechanical.

Last look worksdue to the V-belt transmission of forces from the crankshaft pulley. As for the electric one, such a radiator cooling fan is driven by a special motor. Also, this design requires a separate control system. The intensity of this element directly depends on the readings of the temperature sensor.

Design and principle of operation

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

• Viscous.
• With thermal switch.
• With ECU (electronic control unit).

As for the first type, viscous coupling systems are now almost never found on cars. Basically, they were installed on cars with a longitudinal engine or on massive all-wheel drive SUVs, which also overcame water obstacles. The 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 liquid block, immediately fail. They are no longer subject to further repair and restoration.

Viscous coupling is filled with silicone oil. The latter, when exposed to high temperature, changes its properties and, depending on the level of heating, increases or decreases the intensity of fan rotation. The design of the viscous coupling assumes the presence of such details as a package of driven disksand drive shafts, as well as sealed housing with gel or oil.

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

Motorized elements

As for the electrically driven fans, they consist of the following items:

• Electric motor.
• Electronic control unit.
• Temperature sensor.
• Fan ON relay.

More modern units have two temperature sensors in their design, one of which is installed in the pipe coming out of the radiator, and the second in the thermostat housing. Sometimes it is mounted in a 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 rotation of the impeller. And it is powered by an electric radiator cooling fan motor.

For the 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 (DPKV). After the control unit has received a short signal from all sensors, the information is processed, and the electronics activates the relay, which turns on the fan. During its operation, the system controls the number of rotations and can increase eitherreduce the speed of the impeller. A similar design is now used on most cars and SUVs.

Devices with thermal switch

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

The principle of operation of such a system is as follows. From the temperature sensor, which is installed in the engine block housing, a signal is sent to the scale that is located in the cabin. Further, depending on the readings received and the degree of response of the liquid in the radiator to thermal changes, the fan is turned on or off.

As soon as the temperature of the cooler increases to a certain value, the contacts connected to the power circuit by the impeller are closed inside the thermal switch. Next, an electric current is supplied to the motor, due to which the fan begins to rotate. After the antifreeze temperature drops again, the contact opens and, accordingly, the impeller stops working.

How to find the cause of an element breakage?

As we said in the introduction, a fan failure can cause the power plant to overheat frequently. Therefore, the driver must regularly monitor its performance and, if a breakdown is detected, immediately eliminate it.

How to check this part for serviceability? First, remove the plug from the temperaturesensor. If this element is single, its serviceability should also be checked. This is easy to do - just manually close the terminals in the plug using a small piece of wire. If the temperature sensor is double, then to check it, you must first close the white-red, and then the red wire. Ideally, after this, the radiator cooling fan should spin slowly.

Next, you need to short the red and black wires. In this case, the impeller should rotate as fast as possible.

But what if the radiator cooling fan does not turn on even after several attempts to close it? Conclusion - the temperature sensor has failed or the fuses have blown. The latter are verified as follows. The fan connector on the white-red or black-red wire is supplied with current from the battery terminal with a positive charge. At the same time, power is supplied from the negative terminal of the battery to the brown wire. If the radiator fan of the cooling system did not work after these manipulations, then it is time to replace the impeller itself. Otherwise, it is recommended to inspect all the connectors and plugs that go from the temperature sensor to it.

What should I do if the radiator cooling fan won't turn off?

If the node is put into operation immediately at startup and never turns off (and this should not be), this indicates a breakdown of the node's switch-on sensor. How to check this element for serviceability? For thisyou need to turn on the ignition and remove the wire tip from the sensor. The fan should then turn off. If the impeller still continues to work, the sensor should be replaced. It should also be remembered that with such symptoms, the radiator cooling fan motor is in absolutely working condition, and it is not advisable to check it in this case. But it can also happen that the oxidized terminals turned out to be the source of the malfunction. When diagnosing, they should also be examined and, if necessary, clean the contacts.

Can the fan be repaired?

In some cases, it makes no sense to completely change the part for 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 mounts, it is recommended to disconnect the negative terminal of the battery and remove all wires that go to the fan. Then you need to unscrew the fasteners of the device and take it out.

In some cases, it happens that the culprit of malfunctions is banal dirt. Therefore, after successful dismantling, the fan blades are thoroughly cleaned of dust and other deposits. This is best done with a brush.

In addition, a breakdown may be due to poor contact of the wires. This phenomenon occurs due to the oxidation of the elements in the connecting plugs. Next, you need to check the performance of the rotor winding. Sometimes the radiator cooling fan does not work due to a short or open circuitthis part of the system. In this case, you should inspect each turn.

However, there are elements in the design of this node that cannot be restored. In addition to temperature sensors, the electric motor of the radiator cooling fan cannot be repaired. What does it say about failure? It is possible to determine the non-working state of the electric motor by the state of operation of the impeller. If during the overheating of the power plant it does not turn on, most likely the radiator cooling fan motor has become unusable. In this case, it is urgent to replace it.

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 vibration. But if this sound of his work exceeds the limit, so much so that the engine itself is not audible, this indicates a number of malfunctions. So, why is the radiator cooling fan of VAZ cars noisy? There may be several reasons:

1. Unscrewed bolt securing the impeller to the pulley (screw the part).
2. Broken off blade (replace fan).
3. Lack of lubrication on the electric motor.
4. Broken bearing (replacement only here).

Conclusion

So, we found out why the radiator cooling fan is not working, and also considered how to diagnose and repair it.

As you can see, this nodeis of great importance for the car. Its breakdown will certainly make itself felt in the form of regular engine overheating. But after the first such malfunction, the risk of failure of parts of the cylinder-piston group increases significantly. Therefore, do not postpone this problem until later.