The hot summer is approaching, and for auto parts suppliers and auto repair workers, radiator fans will come into contact more frequently. In the hot summer, engines tend to heat up more easily, and at the same time, the use of air conditioners requires the condenser to have better heat dissipation. So, let's take a look at the common faults and causes of radiator fans together! 
Function: 1. By ventilating and cooling the high-temperature coolant inside the engine cooling box, the working temperature of the engine is reduced. 
2. To facilitate the ventilation of the condenser in the air conditioning system and lower the temperature, the state of the refrigerant passing through the condenser is changed from a high-pressure gas to a high-pressure liquid. As a result, when passing through the expansion valve later, it will be more atomized, achieving better air conditioning cooling performance. 
3. In vehicles equipped with exhaust turbochargers, the compressed air is cooled and cooled through various cooling methods such as the intermediate cooler and the turbocharger heat exchanger. The fan of the radiator assists in the ventilation and cooling process. 
4. For some models, an oil radiator specifically for the transmission needs to be installed at the front end of the engine compartment, along with a fan for cooling. During the vehicle's operation, the airflow flows from front to back towards the radiator water tank, condenser, and other radiators. It has the function of assisting in ventilating and cooling the radiator by itself. 
The radiator fan is mainly used for the following two purposes. 
During vehicle operation, there is an airflow passing through the radiator. However, due to the engine cylinder block, the airflow passing through the radiator becomes disordered and fails to achieve further cooling effects. In such cases, the assistance of the radiator fan is required. Once the cooling conditions are met, the fan rotates and absorbs the wind from the front to the back. At this point, the wind direction is consistent with the airflow direction, allowing more air to pass through the radiator more smoothly and achieving a better cooling effect. 
2. Even if the vehicle stops in place, if the engine or the condenser requires cooling, the radiator fan will rotate, and the generated airflow will pass through the radiator to achieve the cooling effect. 
Types: 
Currently, the motor types of radiator fans are mainly divided into brushed and brushless. The brushed motor is the one that is more commonly used at present, while the brushless electronic type is gradually becoming more widespread in new vehicle models. 
The main structural difference between brushed and brushless electric fans is the carbon brushes. The ones with carbon brushes are called brushed fans, and those without are called brushless fans. The carbon brushes are devices used to transfer energy and signals between the fixed and rotating parts of the electric fan motor. Generally, the carbon brushes are made by adding a hardening agent to pure carbon. Therefore, they are called "carbon brushes". The carbon is printed on a metal frame, which contains springs that press against the rotating shaft. When the motor rotates, the electricity is transmitted to the coil through the frequency converter. 
The difference between brushed fans and brushless fans is: 
1. Lifespan and Durability 
The main component of the carbon brush is carbon, which is a consumable that wears easily. The brush-type fans that use carbon brushes have a short lifespan and are prone to damage. The brushless electronic fans without carbon brushes do not have this problem. For example, the lifespan of a brushed electronic fan reaches 20,000 hours. The lifespan of a brushless electronic fan will reach 30,000 hours or more. 2. The technical performance of the radiator fans is different 
The technical performance mentioned here mainly refers to several factors such as rotational speed, air volume, speed regulation, and control method. Brushed fans were introduced earlier than brushless fans and have relatively mature technology. However, in terms of technical performance, they are inferior to brushless fans. 
The two indicators of rotational speed and air volume show little difference between brushed electric fans and brushless electric fans. Regarding fan speed adjustment, the brushed radiator fans generally cannot be adjusted, at least there is no method to achieve intelligent stepless speed variation. They can only be controlled by temperature control switches and relays, with only two switches for low speed and high speed. The brushless radiator fans do not need to distinguish speed levels to achieve intelligent stepless speed variation. They can always match a more suitable rotational speed according to the heat dissipation requirements. 
Structure: The main components of the radiator fan: motor, fan blades, wiring harness, etc. 
The radiator fan also has components in the form of a supply system consisting of the radiator fan and the air intake hood. 
Depending on the vehicle model, the assembly is divided into two forms. 1. Main fan, secondary fan, and air intake hood 
2. Single-panel air intake hood 
Common Faults: 
1. The electronic fan does not rotate or has abnormal rotation speed. 1. The cause of the fan motor failure is undoubtedly the problem with the fan itself. The most common situation is that the fan motor is damaged, and the fan cannot work. 
2. Fault of the water temperature sensor plug 
In vehicles where the radiator fan is controlled by the engine control unit, during engine operation, the engine control unit regulates the fan's operation based on the data from the water temperature sensor. Usually, when the water temperature measured by the water temperature sensor reaches around 95 degrees, the control unit switches the fan to the low-speed gear. When the temperature is lower than this value, the fan is turned off. When the measured water temperature reaches around 105 degrees, the control unit switches the fan to the high-speed gear, and when it is lower than this value, the fan is turned off. 
Therefore, if the water temperature sensor malfunctions, the control system will not receive the correct water temperature signal, and the fan will not function properly. 
3. In vehicles equipped with thermal switches in the early stage of thermal switch failure, the radiator fan is controlled not by the engine control unit but through the thermal switch and the high-speed relay of the fan. The thermal switch is installed on the radiator and is activated when the water temperature reaches around 95 degrees. The fan operates at a low speed level. When the water temperature reaches around 105 degrees, the contacts of the high-speed relay close, and the fan operates at a high speed level. 
The above content covers the common faults and causes of radiator fans. If you want to know more, please feel free to contact us at any time!