During the use of the tractor, once there is a breakdown, it can often be reflected through external manifestations. Agricultural machinery operators with maintenance experience will further analyze the cause of tractor failures by looking, touching, smelling, measuring, etc., and make full preparations for the next step of maintenance. The common fault symptoms of tractors are as follows：

• Abnormal function

The tractor is composed of various systems. During the working process, the tractor can operate normally only when the systems work in harmony. Usually, it means that the working capacity of a certain system is reduced or the function is lost during the tractor’s farmland operation or transportation, which often leads to The tractor does not work normally, which is a common symptom of failure. Such as: after the engine is turned off, it is difficult to start again, or even unable to start the fire; the power of the engine suddenly decreases during operation, or the power disappears, causing the tractor to fail to work normally; or the clutch is not clear, the speed is unstable, the oil pressure is too low, and the brake fails. And so on. All indicate that the working conditions of the tractor have changed, indicating that the tractor has failed, and the driver is required to find out the cause of the failure and repair it in time.

• The sound is abnormal

 When the tractor is working normally, there will be no abnormal knocking or vibration sounds, or there will be abnormal sounds from certain parts that should not make sounds. However, during the working process, the tractor has undue knocking sounds, or the sound of blasting from the exhaust pipe, or the large friction sound of the contact parts, all of which indicate that some parts of the tractor may be malfunctioning. The operator should carefully search for the sounding part, find out the cause in time, and eliminate the abnormal sound.

• Abnormal temperature

 Under normal circumstances, the water temperature, oil temperature and exhaust temperature of the tractor should be kept within the specified range. If the temperature is too high, the engine body, brake, generator, etc. will overheat; or the cooling water is insufficient, the water tank and Too much scale in the water channel, poor heat dissipation; too late oil supply time; insufficient or too dirty lubricating oil; too small valve clearance; body parts. Therefore, the operator must pay attention to find out the specific reasons for the abnormal temperature and carry out maintenance in time.

• The color of exhaust smoke is abnormal

 During the working process of the tractor, we know that the normal combustion products of the engine are carbon dioxide and a small amount of water vapor. If the combustion is abnormal, the exhaust gas contains unburned carbon particles, hydrocarbons, carbon monoxide or a large amount of water vapor, in addition, there are hydrogen oxides, etc. If there is water in the diesel oil, the engine is too cold, the atomization of the fuel injector is poor, the cylinder liner or cylinder head is damaged and leaks, etc., the exhaust pipe emits white smoke; when the engine is overloaded, the fuel supply time is too late, and the fuel supply Too large, poor atomization of the injector or oil dripping, blockage of intake and exhaust pipes, resulting in insufficient intake air and exhaust exhaust; wear and tear of valves, cylinder liners, pistons and piston rings, etc., will cause black smoke from the engine ;The oil level of the oil sump is too high, the oil ring is seriously carbon-deposited or stuck and loses the oil-scraping effect, the piston ring is insufficiently elastic, or the ring mouth turns to the same direction, causing the oil to jump up, the gap between the valve guide and the valve stem is too large, Engine oil is sucked into the cylinder liner, and the oil level of the air filter oil pan is too high, which will cause blue smoke from the exhaust pipe. When the color of the exhaust smoke is abnormal, it is often accompanied by the phenomenon that the engine is weak or difficult to start. Therefore, experienced drivers can judge the fault from whether the exhaust color is normal.

• Abnormal smell

 During the working process of the tractor, if the gas from the exhaust pipe smells of incompletely burned oil, if there is brake dragging, the clutch and steering gear slip severely, it will emit a burning smell of the friction plate, or there is a short circuit, wire Rubber smell from burning etc. During work, once you smell an abnormal smell, you should stop immediately and find out the fault.

• Abnormal Consumption

 The performance is that the amount of diesel oil used has increased, and the amount of diesel oil consumed by the same workload has increased significantly compared with the previous work; the engine oil is also much more than before; in addition, the amount of cooling water is also consumed too much, all of which indicate that the consumption of the tractor Abnormality is the main performance of failure.

•  Abnormal appearance

 By observing the appearance of the tractor when it is working, it is also possible to determine whether the tractor is faulty. Such as water leakage, oil leakage, air leakage; black smoke, white smoke, blue smoke, etc. from the exhaust pipe, as well as abnormal external performance such as vibration, dislocation, and deformation when the tractor is running, all of which can be used to observe the faults of the tractor.