Industry knowledge

A long shriek or harsh noise

Although the surface of the conveyor pulley is stained with sand and other dirt or the used conveyor belt is installed reversely, it will cause the conveyor belt to make a long-time squeal or harsh noise, but it is usually caused by the improper assembly of the auxiliary mechanism driving device.

If the above noise occurs in a new car that has not been driven for a long time, it may be caused by the poor assembly quality of the original manufacturer. Check the relevant components that you think may cause the failure. If the above noise occurs in an old car, you should consider whether you should completely replace some accessories of its auxiliary drive. Carefully observe the components that may have been replaced (such as alternator, power steering pump, etc.). ）Check whether the mounting bracket is firm and reliable. At the same time, pay attention to whether there is gasket or bushing falling during installation, which may also lead to inaccurate assembly of conveyor pulley.

It is mentioned that dust or sand between the conveyor belt and the pulley can also cause the above noise, so if the car works in a dirty environment, please check whether there is dust on the surface of all the pulley. The rush to buy air tells me it's necessary.

Take the timing gear conveyor belt as an example, it should be adjusted immediately after installation. This is why the direction of rotation of the timing gear belt is marked. If the timing gear belt is removed for other maintenance work and then installed upside down, you will hear a sharp screech when the belt is running. You try to reverse the installation direction of the conveyor belt to see if the fault disappears.

The continuous hissing or creaking increases with the increase of engine speed, which usually means that the bearing of auxiliary transmission mechanism is short of oil. With the help of stethoscope, you can further hear the noise. Then remove the drive belt and turn the suspected faulty part by hand. If it is difficult to rotate, or the sound is very loud, do not hesitate to replace the bearing or corresponding parts. However, it should be noted that when replacing the components of the auxiliary transmission mechanism, do not forget to replace the belt tensioners and automatic tensioners.