The three situations of the car indicate that it is time to change the brake oil: if the car owner only judges whether there is a problem with the brake oil, it can be judged from the brake feeling. If these three situations occur during the driving of the car, it indicates that it is time to consider changing the brake oil (after excluding the problems of tires, brake pads, etc.). 1、 When the car runs normally at a speed of more than 40km/h, the braking distance will be significantly longer if the car brakes heavily. After excluding the brake pad, it can be basically concluded that there is a problem with the brake oil. 2、 When the car brakes, the braking force is light or heavy. When the brake oil deteriorates, the water content exceeds 2.5%. Frequent braking produces high temperature, which turns the water in the brake oil into steam, resulting in a large number of bubbles in the brake oil, which will lead to unstable braking force. 3、 The brake pedal will become soft when pressed down. Deterioration of brake oil will make the brake pedal feel soft even when pressed down to the end. Especially after continuous and frequent braking, the feeling of stepping on the brake pedal will be much softer and more elastic than before. The three situations of the car indicate that it is time to change the brake oil. Whether we change the brake oil regularly or according to the situation, we should pay enough attention to it. The brake force is the most basic safety guarantee. In normal driving, we must ensure that the brake system is safe.
Some riders ask, isn't the role of oil lubrication? Why is the oil added to the engine reduced? Is it difficult to "burn oil"? In fact, the engine oil will be sent to the cylinder for lubrication and cooling. Although there is an oil ring on the piston to prevent the oil from entering the combustion chamber, it is not absolute. As the wear gap of the ring increases, some will enter the combustion chamber and be burned. Engine lubrication basically includes pressure lubrication and splash lubrication. During operation, the oil will volatilize and consume additives due to pressure change, high temperature, heat dissipation and other reasons, so it will slowly decrease, but the amount is small. It is very important to check and change the oil regularly according to mileage, time and oil quality.
Fault diagnosis and troubleshooting of car radiator fan 1. The radiator fan does not rotate when the car is driving? Cause: 1; The engine water temperature does not meet the starting conditions of the cooling fan, and the temperature is low. 2； The engine diagnostic apparatus can be used to test the function of the cooling fan. If the cooling fan can rotate normally, the circuit is normal. Check the thermostat. Fault 2. The car cooling fan does not turn to the air conditioner and does not cool. reason. First, check the temperature control switch of the electronic fan. If the switch is OK, check the fault of the electronic fan itself. Only when the electronic fan operates normally can it cool the air conditioning evaporator to cool the air conditioning system. Fault 3. The reason why the radiator fan of the car engine does not turn at high gear is that the engine water temperature is high mainly because the electronic fan does not start. After the electronic fan fault is eliminated, the water temperature will be normal. If the electronic fan does not work, first check whether the connector is in poor contact, check the power supply and grounding of the electronic fan, check whether the fan is stuck, check whether the fan motor is burned, etc. These factors will cause the electronic fan to fail to start. It is recommended that the vehicle should go to the 4S store for maintenance in time, and drive on the road after troubleshooting. Fault 4: The air conditioning cooling fan makes a loud noise. Cause: check whether there is a grinding shell on the fan, check whether the fan leaf of the fan is deformed, whether the bearing is damaged, and whether foreign matters enter the fan. Fault 5: The reason why the cooling fan starts frequently after stalling is that it cools the engine. Check and judge the radiator fan failure of the car. The cooling system of ordinary cars also stops working after the engine stops, which often causes the temperature to rise after the engine stops, causing damage. So now high-end cars are equipped with the automatic cooling function. The power supply of the radiator is directly connected to the battery. The engine temperature is still very high after the flameout. Therefore, the cooling fan still works for a period of time, and stops after the temperature is cooled, so as to avoid auto ignition caused by high temperature.
The vacuum degree of the intake pipe is abnormal, and the air leakage of the intake pipe has the following effects on the engine: (1) The abnormal vacuum degree of the intake pipe will cause the engine to run weakly. If the vacuum degree of the intake pipe is very low at idle speed, it means that there is air entering the intake pipe from the bypass, because this part of air has not been metered by the air flow meter or controlled by the throttle valve, The measured value of the air flow meter must be lower than the actual intake air volume, and the electronic control unit (ECU) determines the basic fuel injection volume based on the air flow meter and other signals, which results in less fuel injection, too lean mixture and weak engine operation. (2) The abnormal vacuum degree of the intake pipe will make it difficult for the engine to start. For example, for a certain model, a round blind cover at the end of the pressure stabilizing box on the upper part of the intake manifold has fallen off. Due to the excessive air volume, the mixture is too thin, resulting in difficult engine starting. (3) The abnormal vacuum degree of the intake pipe will affect the reduction of the vacuum degree of the exhaust intake pipe, increase the load of the engine and the temperature of the combustion chamber, thus increasing the maximum temperature of the exhaust gas in each cycle, thus increasing the NOx content in the exhaust gas. (4) If the vacuum degree of the intake pipe is abnormal, the idle speed will be unstable. If the intake pipe leaks, the air flow meter cannot measure the real intake air volume, which causes the ECU to control the intake air volume inaccurately, resulting in unstable engine idle speed.
