When the loader is idling, it can hear uniform and slight exhaust sound; When running at high speed, it will sound steadily. If the sound increases, accompanied by power decline, increased fuel consumption, increased vibration and other phenomena, it can be judged as abnormal sound. In case of abnormal sound of the engine, the types and possible causes of the sound can be judged according to different technical conditions, different sounds, different working conditions and spatial positions of each cooperation, the location and sound characteristics of the sound, as well as the timing and change law of the sound.

（一）气门敲击声在气缸盖罩部位有清脆的金属敲击声，当柴油机在中、低速变速时，敲击声更为明显、清脆。出现有规律的“哒、哒”声，主要是由于气门间隙过大造成的。柴油机温度升高或用“断缸”方法试验时，响声均不发生变化。

（1） There is a crisp metal knocking sound at the cylinder head cover. When the diesel engine changes speed at medium and low speed, the knocking sound is more obvious and crisp. Regular "Da, Da" sound is mainly caused by excessive valve clearance. When the temperature of diesel engine rises or the "cylinder breaking" method is used for test, the sound will not change.

（二）矿井装载机的活塞销响的主要原因是活塞销、连杆衬套或活塞销座孔磨损，导致配合间隙过大，活塞销在运动中发生撞击而发出响声

（2） The main reason for the piston pin noise of mine loader is that the piston pin, connecting rod bushing or piston pin seat hole are worn, resulting in excessive fit clearance, and the piston pin makes a noise due to impact during movement

（三）活塞敲缸响的常见和主要的原因，是因为活塞与气缸壁磨损，配合间隙超过一定的限度，活塞在上下运动的过程中发生摆动，敲击气缸壁而发出铛铛的响声。

（3） The common and main reason for piston knocking is that the piston and cylinder wall are worn, and the matching clearance exceeds a certain limit. The piston swings in the process of up and down movement, knocking on the cylinder wall and making a clang sound.

（四）连杆轴承响的主要原因，是轴颈与轴承磨损，轴承合金层烧坏、脱落、轴承盖（瓦盖）松动，轴承转动（轴瓦走外圆），做功的瞬间相互撞击而发响

（4） The main causes of the connecting rod bearing sound are the wear of the journal and bearing, the burning and falling off of the bearing alloy layer, the loosening of the bearing cover (pad cover), the rotation of the bearing (the bearing pad goes to the outer circle), and the sound is caused by the instantaneous impact of work

（五）曲轴轴承响的原因与连杆轴承响相同，其特点为：响声较敲缸、活塞销和连杆轴承响沉闷。

（5） The reason for the crankshaft bearing noise is the same as that of the connecting rod bearing. Its characteristics are: the noise is more dull than that of knocking the cylinder, piston pin and connecting rod bearing.

（六）凸轮轴轴承响常见和主要的原因，是凸轮轴与轴承（轴套）磨损，配合间隙过大；轴承合金层烧坏、脱落或轴承外径与座孔轴承“走外圆”。

（6） The common and main cause of camshaft bearing noise is the wear of camshaft and bearing (shaft sleeve) and excessive fit clearance; The bearing alloy layer is burnt out or falls off, or the outer diameter of the bearing and the seat hole "go to the outer circle".