The cold wave has arrived, and many car owners have discovered abnormal noises in their vehicles during their use in recent days.
If abnormal noises occur after the arrival of a cold wave, then these abnormal noises are often not faults.
Types include: crisp bursting sound, sharp whistling sound, low-frequency friction and abnormal noise, increased wiper noise
These four situations are basically normal phenomena. First, let’s explain the crisp bursting sound. This sound comes from the thermal expansion and contraction of metal; The sound will come from the exhaust system after long-term driving of fuel vehicles, plug-in hybrids and extended-range vehicles after using hybrid mode for a long time. The exhaust system of a fuel vehicle includes a three-way catalytic converter and a particulate matter trap. The operating temperatures of these two assemblies are very high, and their starting and operating temperatures often exceed 200°C (Celsius)! And the maximum temperature can exceed 600 degrees Celsius.
High temperature will cause thermal expansion and contraction of metal materials, which will greatly reduce the exhaust volume after parking. The two assemblies will quickly start to cool down; during the process of cold contraction, there will be a probability of extrusion at the joints of parts. If friction occurs, noise will inevitably occur. Therefore, this sound will occur once the car is stopped after driving for a long time. It sounds like it is broken somewhere, but it actually has no effect.
Rubber material·Hot soft and cold hard
1. Timing belt
The other three abnormal noises come from the impact of low temperature on the hardness of rubber materials. Although various types of synthetic rubber used in automobiles have good cold resistance, low temperature will still cause the rubber to The hardness of the car becomes higher; and rubber parts are used in many parts of the car, including the core engine. Part of the engine uses a metal timing chain, and part of the engine uses a rubber timing belt.
It is said that the belt is actually made of rubber, so the hardness will of course be affected.
If the vehicle is parked in a low temperature environment for a long time, the timing belt will become very hard; then sliding friction may occur during cold start, and of course there will be sharp abnormal noises in the process. If the vehicle has traveled about 80,000 kilometers and the timing belt has not been replaced, the frequency of abnormal noise is relatively high. At this time, you can consider replacing the timing belt.
2. Sealing strip
When driving on a relatively rough road, abnormal noises may occur in many parts of the car body, but the sound is relatively dull; the reason for these abnormal noises is the sealing strip of the car door. When you open the door, you will see a circle of black Sealing strips, these sealing strips are all rubber strips.
Its function is to fill the gap between the door and the body to avoid friction damage. Of course, it also has the function of dust prevention and noise reduction. The increased hardness of the sealing strip will reduce the vibration damping effect, and the car body will deform to a considerable extent during the ups and downs, but it will change back after returning to a flat road surface. The sealing strip that is pressurized and hardened during the process will also cause Abnormal noise. Many car owners will add sealing strips to all gaps. In fact, it is completely unnecessary. Some gaps are spaces where the car body deforms. After filling with sealing strips, abnormal noises are more likely to occur.
3. Wiper
Whether it is a bone wiper or a boneless wiper, the position where it contacts the car glass is a rubber strip.
Low temperature will certainly harden the rubber strips, and the wipers may bounce slightly when swinging rapidly. Abnormal noise is a normal phenomenon; and there is no good way. Silicone rubber and nitrile rubber are among the synthetic rubbers. It has the best low-temperature resistance, but wiper strips made of these two materials will also make abnormal noises, so don’t worry too much.
That’s all about the knowledge about low temperature and abnormal noise.
Editor: Tianhe Auto-Automotive Science Island, published by Tianhe MCN, welcome to like and comment
