Engine cooling fan: types, diagnostics, purpose, device.

For efficient operation of the engine, appropriate thermal conditions are required. When fuel burns, not only exhaust gases are released, which ensure the operation of the engine, but also thermal energy. To avoid engine overheating, it is cooled using various liquids (antifreeze, antifreeze, distilled water). The fan is necessary to reduce the temperature of the coolant.

TYPES OF COOLING FANS

There are four types of fans:

• with direct drive from the timing belt (chain);
• with direct drive from the alternator belt;
• driven by a timing belt or generator and a thermal coupling;
• with electric drive.

A fan directly driven by a timing belt or chain was used on cars that were produced before the nineties of the last century. Moreover, foreign car manufacturers abandoned such a system back in the seventies of the last century. The only dubious advantage of such a drive is the smaller number of belts, because the timing drive covered the pump, fan, crankshaft and camshaft. Often in such systems, the belt or chain was tensioned using a water pump (pump) without installing the adjusting roller.

A fan driven by an alternator belt became more widespread on inexpensive cars produced before the 2000s. Compared to timing belt/chain drive, this system has several advantages. The main one is the lack of influence of the fan on the operation of the timing system. In the event of a fan jam or other malfunctions, the operation of the timing belt is not disrupted and the car can continue to move under its own power.

A fan with a thermal coupling, regardless of the type of drive, has the main advantage - it better controls the thermal regime of the motor. Until the clutch is heated, it weakly transfers rotational energy to the fan, so even at maximum engine speeds its rotation speed is low. As the clutch heats up, the transmission coefficient increases and the fan rotation speed becomes increasingly dependent on engine speed. Therefore, when the engine warms up, the fan reduces the temperature of the coolant slightly, and when it heats up close to maximum, its operating efficiency increases.

An electrically driven fan is the most efficient and is used on most modern cars. It turns on only at a certain coolant temperature, thanks to which the engine quickly heats up and operates in a comfortable mode.

Diagnosis of cooling fan faults

Neither the most innovative electric motor with high power, nor the ultra-reliable control unit or controller is able to protect the cooling system one hundred percent from breakdowns. Considering that a failed cooling fan that blows in the wrong direction or does not rotate at all can cause engine overheating, it is necessary to constantly monitor its normal functioning.

Timely repair of system components will save your car from many troubles, but it is important to correctly determine the cause of the fan failure. In other words, you first need to find a problem where, for example, the crankshaft speed controller or control unit or electric motor does not work. Any driver can diagnose fan malfunctions based on the recommendations below.

The check should begin by dismantling the connector (plug) of the temperature sensor and inspecting it. In cases where the sensor is single, you need to take a small piece of ordinary wire and close the terminals in the plug. If the fan is working properly, the control unit or relay should give a command to turn it on when closed. If the device we are interested in does not turn on during such a test, this means that it requires repair or replacement.

If there is a double temperature sensor, the testing principle changes slightly and is performed in two stages:

1. The red and red-white wires are closed. In this case, the fan should rotate slowly.
2. Red and black wires are connected. The rotation should now speed up significantly.

If rotation is not observed, the fan will have to be removed and a new device installed in its place. If the radiator cooling fan is constantly running (blowing without interruption), there is a possibility that the sensor for its activation has failed. It is not difficult to verify this suspicion. You must turn on the ignition and then remove the wire tip from the sensor.

If the device does not turn off after this, you can safely buy a new regulator (sensor) for turning off the device. Situations where the radiator cooling fan is constantly running are not uncommon, and now you know how to solve this problem. It also makes sense to check the fuse in cases where you doubt the functionality of the mechanism described in the article. This is done like this:

• from the positive terminal of the battery, power is supplied to the red-black or red-white wires in the fan connector;
• From the negative terminal a charge is supplied to the brown wire.

If the regulator or unit does not respond (the device does not turn on), check the temperature sensor wire (all connectors and plugs on it). The cable may need simple repairs (for example, insulating it, replacing the plug). If the problem is not in the wire, then you will have to purchase a new fan, since yours is broken.

ELECTRIC COOLING FAN OPERATION SYSTEM.

When the fan heats up, the thermal switch sensor (located in the lower left corner of the radiator) closes a low-current circuit going to the unloading relay. I note that this sensor breaks the “minus” going to the relay. The “plus” relay comes from the ignition switch and is regulated by fuse No. 19 (located inside the car on the left in the instrument panel). The sensor is most often 3-pin. The brown wire takes the negative wire from the car body. The other two wires (striped), when the contacts in the sensor are closed on them, supply a “minus” to the unloading relay. Depending on the degree of heating of the coolant, the sensor closes a circuit going to relay No. 214 (first speed) or a circuit going to relay No. 217 (second speed). Relay No. 272 ​​and temperature sensors located on the upper pipe of the cooling system (blue and gray) do not participate in any way

, contrary to popular belief.

Relay No. 272 ​​only works when the ignition is turned off in the aftercooling mode (I will not touch this mode). Further, when receiving a “minus” from the sensor and a “plus” from the ignition switch, the unloading relay closes the power contacts and supplies “PLUS” directly to the cooling fan. The “MINUS” fan is taken from the car body (from the side member). The power “PLUS” relay is taken from the battery under the protection of a 40A fuse (60A if there are 2 fans on the radiator), which is located behind the decorative trim to the left of the driver’s foot (you won’t find it, and if you find it, you won’t get it). Well, that's all. Depending on which relay receives “minus” from the sensor, this speed will turn on.

Radiator fan malfunctions and their consequences

The main task of the engine fan is to “suck” cooled air from the outside through the radiator into the engine compartment of the car. In fact, cooling is carried out by a liquid system, and blowing only speeds up this process. On the other hand, at high ambient temperatures, as well as when the car sits for long periods in traffic jams without additional cooling, the engine can become very hot. This means that the serviceability of this unit should not be neglected.

Engine fans with different numbers of blades

Main malfunctions of the engine cooling fan:

• Doesn't turn on. Such a malfunction may be the result of a breakdown of the fan drive (broken belt, destruction of the clutch, faulty electric motor, oxidation of contacts) or inaccurate operation of the temperature sensor.
• Continuous operation and the impossibility of turning off until the vehicle stops completely (except for cars with a mechanical drive). Most often, such a breakdown is associated with a malfunction of the temperature sensor (thermostat) or jamming of the clutch.
• Untimely switching on. Turning on earlier is usually not a problem. If startup occurs late, a temperature sensor may be installed that is designed for operation at low temperatures (for example, the car is not suitable for regions with hot climates). In this case, the sensor must be replaced.
• Reverse direction of air injection. Occurs when the motor poles are connected incorrectly.
• Destruction of the impeller due to wear and increased loads.

When the cooling fan is correctly connected, the direction of air flow is always towards the engine.

Preventing the condition and cleaning the engine cooling radiator fan from dirt should be performed at least once a year. The cleaning procedure can be performed without dismantling the unit using conventional brushes. If replacement is required, it is better to contact specialized repair services, which will eliminate errors in diagnostics, selection of the desired fan configuration and its connection.

Radiator fans - purpose and design

The radiator cooling fan is used for air cooling, which, together with liquid cooling, ensures optimal temperature conditions for the engine. To increase the efficiency of liquid cooling, a radiator is used: oncoming air passes through its cells and cools the liquid. But at low speeds or in city traffic jams, the air flow is insufficient. To avoid overheating, a fan is turned on, which directs air to the radiator, cooling it.

On older models and modern SUVs with a longitudinally mounted engine, a mechanical cooling fan drive is used. In older cars it works constantly; later they began to install a viscous coupling, which turns it off if necessary. Used on large trucks and SUVs. The advantage is that it is not afraid of water, unlike electric fans.

Electric cooling fans test

With the onset of summer, some motorists are faced with the need to replace the electric cooling fan. How not to make a mistake with the choice of such an important component, on which the issue of engine “survival” in traffic jams and in hot weather often depends?

The electric fan produced by the Kaluga Automotive Electrical Equipment Plant (KZAE) model 70.3730 actually has a much wider application. It can be installed on the engines of almost all domestic cars (ZAZ, VAZ, AZLK, IZH, GAZ and ZIL). The main thing is that its parameters are suitable - 110 W and 2600 min-1, as evidenced by the corresponding inscription on the packaging and the installation drawing. KZAE mod. 70.3730 has an 8-blade impeller without a rim, unlike its competitors in the test. It is packed in a cardboard box. However, apart from the electric fan, nothing else could be found in it. The manufacturer's guarantees were also unknown.

Before we started testing the electric fan, we measured the diameter of the impeller (see table at the end of the article). The next step was to measure energy consumption and impeller rotation speed. The measurements were carried out in two modes: at the moment of start-up and during steady operation. Based on the measurement results, it turned out that the test subject was the most “economical” among competitors, but the impeller rotation speed turned out to be the lowest.

Having completed the measurements, we began disassembling the fan. The KZAE electric fan impeller has the same mounting as PEKAR and Kraft, and they can be interchangeable with each other. It is held on the shaft using pins, which are inserted into a through hole on the shaft of the electric motor. The impeller is secured with a regular nut and washer. The KZAE electric motor is dismountable, unlike the LUZAR fan. It is structurally made with two bearings: on one side the shaft rests on a ball bearing, on the other on a bushing (see photo). This collapsible design is more preferable from the point of view of maintainability. The electric motor brushes have a cross-section of 6.5x6.5 mm and a length of 11 mm. The connection of the brush units is made using wires. In this case, mediocre soldering was discovered.

The electric fan from St. Petersburg auto parts manufacturer PEKAR is much more specific, since it has an address message in the form of catalog number 2103-1308008. It also has an 8-blade impeller and rim to reduce vibration and noise. In addition to the packaging, a technical data sheet and fasteners for mounting the electric fan were included in the cardboard box. Manufacturer's warranty is two years.

Having carried out measurements as with the previous test subject, we disassembled the fan. The PEKAR electric fan impeller, as already noted, has the same mounting with KZAE and Kraft and can also be interchangeable with each other. It is held on the shaft by pins inserted into a through hole on the motor shaft. The impeller is secured with a nut with a lower toothed rim. The electric motor is also structurally made with two bearings. The cross section of the brushes is 6.5x6.0 mm, length - 11 mm. The brush units are connected using wires, just like in KZAE, but the soldering of the wires is performed at a more technological level. The electric fan under the German brand Kraft (KT 104500) is exactly like the one from St. Petersburg. At the same time, we experienced a certain feeling of déjà vu. Exactly the same impeller and engine dimensions. However, this is where the similarity ends: no passport, no fasteners, and the warranty is only one year. Having measured the diameter of the impeller (note that for fans with a rim, the diameter of the impeller was measured along the inner rim), as well as the energy consumption and rotation speed of the impeller, we began to disassemble this fan and found complete similarities with the PEKAR electric fan.

The LUZAR electric fan is strikingly different from its counterparts with eight profile blades united by a single rim. In addition to the fan, we found a technical data sheet and fasteners in the cardboard box. The warranty for this electric fan is two years. Based on the results of measurements of energy consumption and impeller rotation speed, the fan turned out to be in the “golden mean”. At the same time, it has the highest impeller rotation speed.

Analysis showed that the impeller of the LUZAR electric fan is held by a groove on the electric motor shaft and is fixed with a nut with a left-hand thread that has a lower toothed rim. In addition, the nut is secured with a thread locker. Due to this, the impeller of the LUZAR electric fan is not interchangeable with other electric fans. The LUZAR electric motor is also made according to a two-bearing design, like the previous tests, but on two ball bearings. It follows from this that collapsible structures are more preferable from the point of view of maintainability, at the same time, two bearings on the shaft make the structure more reliable and durable. Let's move on to the brush assembly. The electric motor of the LUZAR fan uses spark arresting chokes (twisted copper wire). This design significantly extends the life of the product. The cross section of the brushes is 7.0x8.0 mm with a length of 20 mm. The connecting wires of the brushes also have a larger cross-section (help reduce heating). To connect the brush assemblies and spark-extinguishing chokes, brass plates are used, to which the supply wires and brush wires are welded with special conductive welding pliers (in all likelihood, this leads to a decrease in transition resistance and less heating).

When examining all four rotors in the LUZAR fan electric motor, a double rotor winding was discovered. Its use precisely leads to increased magnetic flux and electric motor power with the same dimensions. Comparability of prices for the tested fans revealed some inadequacy in the supply of goods according to the “price-quality” criterion. A higher price is requested for frankly low quality. If we take into account the data obtained during testing, we are inclined to give our preferences in favor of the LUZAR fan.

Viscous coupling fans

A system based on a viscous coupling is not common. It is equipped with vehicles with a longitudinally mounted power unit, and it is also used on large SUVs used to overcome water obstacles. This is due to the operating principle of such a cooling fan. The viscous coupling is a completely sealed design and is therefore reliably protected from water penetration. Under its influence, electrical systems will instantly fail. The viscous coupling is filled with special silicone oil or gel. It changes its properties when exposed to temperatures. The rotation speed of the device will be reduced or increased depending on the heating level. This cooling fan consists of a sealed housing filled with silicone liquid, as well as drive and driven shaft disk packages. The operating principle is based on the transmission of rotation from the drive to the driven shaft due to disk packs.

Best Cooling Fan Manufacturers

There are several manufacturers whose fans cope well with the load. Each brand has its own advantages over its competitors, but the main feature of the presented fans is considered to be reliability compared to analogues.

SAT

Description of the design. Among manufacturers of elements for the cooling system, the SAT brand stands out for its large assortment of spare parts on the aftermarket. The Chinese fan is low cost and of average quality. The fan in a plastic case can be of several options. Different car models have their own series of radiator fans with different characteristics.

Kinds. Elements with hydromechanical and electric drive are produced. The electric drive is more in demand in the aftermarket.

Life time. The guaranteed operation period is 1 year, but with appropriate care and compliance with operating rules, the actual operation period reaches three years without repair.

Pros of the SAT

1. Little noise.
2. There are devices for various car models, including SUVs.
3. Large assortment at a price lower than analogues.
4. A budget option of average quality that can work for a long time without repair.

Cons of the SAT

1. Marriage may occur.
2. Works weaker than original fans.

Nissens

The Danish company Nissens is one of the most famous manufacturers of cooling systems. The fans are of proven quality.

All requirements of ISO 14001, TS 16949, ISO 9001 certificates are met.

The reliability of aftermarket parts, which are similar in characteristics to the originals, is noted.

Description of the design. What distinguishes the fan is its thickened casing and the use of durable materials that are resistant to corrosion and other types of damage.

Kinds. Among the types of fans produced, you can find all drive options. Electric is considered the most popular, but hydromechanical is also in demand. A separate series of spare parts with mechanical drive is intended for special equipment.

Life time. The warranty period for various fan options varies from 1 to 2 years. The duration of operation itself is not limited, that is, with careful use, the spare part can last more than 5 years.

Pros of Nissens

1. An expanded line of fans and various types of electrically driven devices for popular car brands.
2. Good quality and guaranteed reliability.
3. There are no complaints about the operation of the device.

Cons of Nissens

1. High price relative to competitors.
2. A large number of fakes. It is necessary to immediately check the fan for logos, imprints and defects.

Behr Hella

The Behr Hella brand guarantees high-quality performance of fans for cooling systems in various car brands.

Description of the design. Aftermarket parts have earned a positive reputation for using quality materials that provide long service life.

Kinds. The range includes fans with a mechanical drive for special equipment, hydromechanical fans for SUVs, as well as standard fans with an electric drive.

Life time. The warranty is issued for two years, since aftermarket parts do not differ from the originals. The service life can exceed 10 years if all maintenance conditions are met.

Pros of Behr Hella

1. Guaranteed quality from the leader in aftermarket cooling system parts.
2. Long work.
3. There are no problems associated with increased noise or defective operation.
4. There are few differences from the original fans that are installed when assembling a car on an assembly line.

Cons of Behr Hella

1. High cost relative to other manufacturers from the middle price segment.
2. It is difficult to avoid counterfeits on the secondary market. Most often, they are distinguished by the absence of special brand marks and lower cost.

LUZAR

Luzar has a range of spare parts for the cooling systems of domestic and foreign cars. The difference between the fan will be compliance with GOST requirements, as well as an extended warranty period.

Description of the design. Spare parts are made from high-strength materials that are little subject to wear. They are supplied to factories from trusted foreign suppliers.

Kinds. The range includes fans with electric, hydromechanical and mechanical drives. The most expanded range is for models with electric drive.

Life time. The warranty is valid for 2 years, but due to the high-quality workmanship, which is close to native analogues, aftermarket parts can last up to 10 years without repair or replacement.

Pros of LUZAR

1. Small number of defects, defects and fakes.
2. Good quality at a price lower than foreign competitors.
3. Expanded series for domestic and Asian cars, including hydromechanical ones for a number of powerful cars.

Cons of LUZAR

1. Electrically driven fans have low performance due to a weak motor.

Electrically driven fans

The radiator and engine cooling fan with electric drive has a more complex design than the previous system. In addition, it is more modern, so it is found on many new cars. The device includes an electric motor, a temperature sensor, an electronic control unit, and a cooling fan relay. Most devices have two temperature sensors. One is equipped with a pipe coming out of the radiator. The second sensor is built directly into the thermostat housing, and can also be located in the pipe coming out of the motor. The difference in sensor readings affects the operation of the cooling fan control unit.

Setting the operating mode of the device's electric motor requires an air flow meter, as well as a sensor that monitors the crankshaft speed. The control unit will receive the corresponding signals from all sensors and process them. The cooling fan relay is then activated, which will monitor the rotation speed of the impeller after the system is turned on. Such devices are often installed by car manufacturers nowadays.

A car fan is like a device.

A car fan is like a device that increases the circulation of air passing through the heating and cooling radiator, thereby increasing its efficiency. The fans of such world names as Spal, Ebmpast, Kormas presented in our store can satisfy any request for energy saving, performance, noise and at the same time have reasonable prices. The special structure of the impeller makes it possible to achieve very high efficiency and reduce noise to nothing.

Productivity and energy efficiency are our pillars of success, which have long established us throughout the world. At this stage we supply automotive fans for cars and trucks, as well as for buses and trailers. Spal or Ebmpapst products in one form or another are already present in many systems of modern cars, from the interior air conditioning system to the engine cooling system. You don’t know it yet, but Spal is already in your car!

Fans with thermal switch

Similar mechanisms were installed on cars before the invention of the electronic unit. For example, a VAZ cooling fan is also equipped with a thermal switch. This device is responsible for turning on/off the system's electric motor. The principle of operation of this type of cooling fans is as follows: the signal is sent from a temperature sensor, which is installed in the cylinder block housing on a special scale located in the vehicle interior. This indicator and the response of the thermal switch to changes in the temperature of the liquid in the radiator affect the procedure for turning the engine on and off. If the temperature of the cooler is increased to the maximum, the contacts inside the thermal switch will be closed and connected to the system power circuit. Then current will be supplied to the electric motor, which will cause the fan impeller to rotate. The contacts will open if the temperature drops to the extreme minimum, which guarantees that the device will turn off.

Which radiator cooling fan to buy

There are several rules for choosing a cooling fan. First you need to find out the cause of the malfunction of the old fan. On the secondary spare parts market you can buy individual elements for almost any version of the cooling device. An example would be the purchase of an electric motor, an impeller, and a separate relay.

This option is possible with a new fan that is not worn out. When it wears out, a full replacement is required.

When replacing you must:

1. The selection of a fan is carried out according to the VIN code, that is, an analog or original spare part is purchased that fits all parameters.
2. There are many different parts on the market in every price segment. You should not pay attention to very cheap spare parts, as they may be defective.
3. The choice of manufacturer is made based on the recommendations of car owners and service center specialists. Reviews often show all the advantages and disadvantages of each brand.

It is important that all fasteners match and that the fan is not modified for installation, as otherwise errors and defects in operation may occur.

The fan must also be suitable in terms of power and other parameters. Be sure to take into account the car make, model and engine parameters.

Among the popular brands of air cooling fans are companies that supply spare parts to the aftermarket with a good price-quality ratio. Each type of fan has its own characteristics, as well as parameters that need to be taken into account when choosing.

What to do if the fan breaks down while traveling?

Often a cooling fan breakdown occurs somewhere along the road. If it stops working, then in city mode the antifreeze will definitely boil. Here are a couple of tricks that can help in this case:

• Firstly, if the breakdown occurred on the highway, then in high-speed mode it is easier to ensure airflow to the heat exchanger. To do this, it is enough to move at a speed of at least 60 km/h. In this case, cool air will flow into the radiator in large quantities. In principle, in this mode the fan rarely turns on, so the system will operate normally.
• Secondly, the heating system of the cabin uses the thermal energy of the cooling system, so in emergency mode you can turn on the heating to use the heater radiator. Of course, in the summer, driving with the interior heating on is still a pleasure, but the engine will not fail.
• Thirdly, you can move in short bursts. Before the coolant temperature arrow reaches its maximum value, we stop, turn off the engine, open the hood and wait until it cools down a little. Under no circumstances should you water the unit with cold water during this procedure, so as not to cause a crack in the cylinder block or head. Of course, in this mode the journey will be significantly longer, but the car will be intact.

However, before performing such procedures, you should check why the fan does not turn on. If the problem is in the wiring or sensor, then to save time you can connect the electric motor directly to the battery. Don't worry about the battery running out. If the generator is working, then while the internal combustion engine is running, the on-board system is powered from it. Read more about the operation of the generator separately .

Although in many cars you can replace the air blower yourself, if the car is still under warranty, it is better to use the services of a service center.