What's the abnormal sound of the car belt?

The existence of the most common abnormal noise of the engine depends on the speed state of the engine.

1, abnormal noise only exists when idling or running at low speed. The causes of noise are: the gap between piston and cylinder wall is too large; The piston pin is assembled too tightly or the connecting rod bearing is assembled too tightly; The gap between tappet and its guide hole is too large; Wear of valve cam profile; Sometimes the starting grip is loose, which will make the pulley ring (obviously when shifting).

2. Keep a certain speed of sound disorder, and make short sounds one after another when slowing down sharply. The causes of noise are: the camshaft timing gear is broken or its fixing nut is loose; The crankshaft is broken; Loose piston pin bushing; Excessive axial clearance of camshaft or loose bushing.

3. Abnormal noise occurs when the engine accelerates rapidly, and it still exists when the engine runs at high speed. The causes of noise are: the connecting rod bearing is loose, the bearing bush melts or rotates because of the inconsistent size; Crankshaft bearing looseness or bearing bush burning; Piston pin is broken; The crankshaft is broken.

Method for judging abnormal sound of engine belt;

First, check the engine belt. If there are multiple belts in the car, you can't tell which belt is the problem. You can start the car first and then pour some water on the belt. If the abnormal noise disappears, it means there is something wrong with this belt. You can see if it is loose or of poor quality.

The engine belt is abnormal, so watering it with water is to increase its viscosity, in fact, it improves the viscosity of the belt. But after the water dries, the belt will return to its original state, which is the principle of belt watering.