What is the cause of abnormal noise in the car? What is the reason for the abnormal noise of the car

1. Abnormal sound of the body, this problem is usually due to the insufficient stiffness of the body, which leads to the deformation of the vehicle during driving, the friction or shaking of the door and the frame, or the friction between the steel plates due to dewelding in some places.

2. Methods such as sticking adhesive strips on doors and windows or padding rubber on friction parts may reduce or eliminate abnormal noises, but they do not cure the root cause.

3. The wind noise of some cars is larger, which is related to the styling, if it is confirmed that there is no extra items, the owner himself will not find a way to solve it. There are also some cars that are not fixed well between the body parts and may also cause abnormal noise, which can be solved by tightening the screws.

Related Notes:

1.Lubricating oil in winter has higher requirements for the lubrication of the car, if the oil used in summer must be replaced, the oil that has been used for a long time, the color is black, and the adhesion has deteriorated should be replaced to ensure the smooth start of the engine.

2.The amount of antifreeze must be appropriate, different regions and different models should pay attention to the freezing point and model of antifreeze, the antifreeze that has been used for more than two years should be replaced, and the mixed antifreeze must be replaced for one year. Note that products of different brands and models should not be mixed.

3.The electrolyte in the battery can not be deficient, keep the plate submerged for 10 mm as well, and check the specific gravity of the electrolyte to keep the charge amount, if the battery is not charged enough, it is easy to crack in the cold.

4.Warm air check the heating air pipeline and fan, especially pay attention to whether the defrost air outlet under the windshield is normal, whether the heat is enough, there is a problem with the defrost air outlet, driving in winter will bring many troubles and unsafe factors.

Perhaps, rubber and plastic products are easy to harden in winter, and abnormal noises will occur if there is a gap in the adhesive part.

There are always so many small problems in the process of daily car use, which only the owners of long-term use know. Small problems are the problems of any car, although it does not affect the normal driving of the vehicle, but it is very annoying, and the most annoying of them is the abnormal noise of the car.

There are many kinds of abnormal noise, you should explain what kind of car it is, and the parts of the abnormal noise are the engine, body, and chassis? The characteristics of the abnormal noise, the newness of the car.

Fault diagnosis: check the vehicle, and find that when the car is cold, the engine starts with a "click" sound, and there is no abnormal sound when the engine is turned off and started immediately. When the engine accelerates to 3000r min, a rhythmic "click" sound is heard inside the engine, and the sound disappears when accelerating to 3500r min or 2500r min.

Test drive, abnormal noise appears in 5th gear at 80km h, and the abnormal sound of acceleration or deceleration disappears. First of all, use IT-2 to check the fault code, the vehicle has no fault code, and the control system is normal. The cylinder breaking experiment was done, and the abnormal noise did not change.

Checking the vehicle with a stethoscope reveals that the abnormal noise is coming from the front of the engine, near the timing cover. Remove the valve cover and check that the timing chain is not abnormal. Since the squeak is most pronounced at around 3000 R min, this speed is exactly where the low-to-high conversion of the engine from VVT-I comes into play.

The first cam bearing was removed and the filter element was checked, and no problems were found. No abnormalities were found in the camshaft sprockets and timing chains. Only the crankshaft sprocket was not checked, and the owner did not agree to disassemble the timing cover, and was ready to remove the crankshaft position sensor and check the crankshaft sprocket with a flashlight and lenses.

A problem was discovered when the crankshaft position sensor was removed, with broken crankshaft teeth sticking to the magnetic position at the front of the sensor. At this time, it was basically concluded that the problem was in the ignition timing part of the engine, and it was found that the crankshaft sprocket was damaged, and the chain and other accessories were worn.

Troubleshooting: The reason for the abnormal noise is that the chain resistance increases when the VVT-I is running, and the abnormal linkage with the crankshaft sprocket causes abnormal noise. But why are the sprocket teeth of the crankshaft broken?

The author and relevant maintenance technicians suggest replacing the engine crankshaft, sprocket, chain, VVT-i actuator, crankshaft sensor sprocket, oil pump sprocket, oil pump chain and other accessories. After the replacement, the abnormal sound of the engine cold start disappears.

Fault summary: multinational automobile group adjusted the strategy to China, improve the Chinese market from the troubleshooting of the car can be seen that the root cause of the failure is crankshaft sprocket damage, chain and other accessories wear, resulting in cold car noise. When there is a problem, the IT-2 data flow is not checked, and if the VVT-i turns on the angle data flow during abnormal noise, the fault point can be found relatively quickly.

I hope the subject and netizens are grateful.

There are many reasons for abnormal noise of vehicles, such as abnormal engine noise and abnormal suspension noise. Abnormal noise of chassis parts. Abnormal noise of transmission parts.

1. If the owner is driving at a slow speed, there is an abnormal sound, it may be a sound from the suspension next to Kaipai, such as loose bolts, the vehicle shakes and produces abnormal noise.

2. When you lightly step on the brakes, you find that most of the abnormal noises are caused by problems with the braking system, such as the abnormal noise caused by the brake pads being too thin and the uneven wear of the brake disc and the brake sunrock pads.

3. If the engine belt is loose, there will also be abnormal noise, and the owner can use his fingers to clamp the transmission belt and twist it below 90 degrees, or adjust the tightness, which will reduce the loosening of the belt.

4. Some parts are aging, such as some rubber parts, because of long-term use, it will cause serious wear, and even some parts will break, which will lead to abnormal noise and louder noise in the car.

If there is an abnormal noise in the car, it must be that a certain part is working abnormally or damaged, so once there is an abnormal noise, the owners must check.

On the issue of abnormal noise of automobiles, it is difficult for ordinary car owners to distinguish which ones are abnormal noises and which ones are reasonable abnormal noises. Only nearly 20% of the vehicles that went to the repair shop to detect abnormal noises really had problems. In the case of a turbocharged engine, there is a must be a difference between the sound and the sound of a naturally aspirated engine; Models with engine guards may also make noises due to friction; After some car owners come into contact with different cars, it is likely that due to their lack of understanding of mechanical knowledge, they mistake reasonable abnormal noise as a vehicle failure.

Therefore, learn to distinguish the abnormal noise of the car and avoid wasting time and energy.

The identification of car noise is limited, and it is difficult to use special instruments to measure the sound of the car, and the sound of the car can only be described and compared with the judgment of the sound in daily life. For example, the "rattle" sound caused by the dry friction of the bearing, and the "click" sound similar to the small hammer hitting the cement floor caused by the excessive valve clearance.

1. Correctly distinguish between normal and abnormal sounds.

The vibration of each mechanism in the work of the car will emit a variety of sounds, but the sound does not mean that the car is faulty, in order to avoid unnecessary disassembly, we must first distinguish between normal sound and abnormal noise. The normal vibration sound of each system component (such as the noise on the surface of the engine), the impact sound of the gear when shifting, the air intake sound and exhaust sound of using gas as the working source, and the gear meshing noise are all normal sounds. Abnormal noise (abnormal noise) can be divided into slight noise, general noise and malignant noise according to the impact on the performance of the car.

Slight noise, such as the flashover sound of high-voltage electric leakage, the slight loose sound of rolling bearings, etc., the general volume is small, the degree of wear of the parts is not large, and there is no significant change for a long time, and this kind of fault can still maintain the normal operation of the car without repair.

3. When diagnosing abnormal noise, attention should be paid to creating good auscultation conditions and trying to eliminate the interference of other noises, so as not to affect the accuracy of judgment.

It is best to consciously amplify or reduce the sound, that is, use a screw or other metal rod as a stestological instrument to contact the sound part to amplify the sound, or use a single cylinder fire cut-off to reduce the sound to meet the diagnostic needs. The auscultation site should be kept quiet to minimize human interference.

1. The abnormal noise of the door, if it is one of the doors, because the structure of the door is relatively simple, then you have to see if it is because the screws are not tightened.

2. If your car is with a sunroof, then you have to see if the sunroof has any abnormal noise, the abnormal sound of the sunroof is generally normal, because after driving for many years, the guide rail inside the sunroof will fall with small stones or dust or something, and if the sealing is not strict for a long time, it will produce abnormal noise.

This kind of problem is actually not a big problem, generally you have a luxury car like BMW Mercedes-Benz, he will also have a sunroof abnormal noise.

3. The abnormal sound of the center console, the abnormal sound of the center console is generally related to the overall workmanship and materials of the car. You have to consider whether your car has dismantled the center console before, whether it has installed the navigation cable or something, whether it is still intact when it is installed, or what parts are not assembled?

4. Abnormal noise is on the chassis, or outside the car. In this case, it is generally recommended that you go to the 4S store to find out.