1. The sudden change of working condition
The so-called sudden change of working condition means that the working condition of the car suddenly appears abnormal. This is a common symptom of failure. For example, if the engine suddenly turns off, it will be difficult to start, or even start; the engine will suddenly decrease in power during driving, and the driving will be weak; sudden braking failure or deviation or even failure in driving. The symptoms of this type of malfunction are obvious and therefore easy to detect.
2, abnormal noise
The abnormal sound of the car during driving is the alarm of the car. Suddenly, abnormal noise is emitted during driving. As the driver should be aware of the problem with the car, he should immediately stop the car and check that the vehicle should not be allowed to operate with disease.
3, exhaust smoke is not normal
During the operation of the engine, the main components of normal combustion products should be carbon dioxide and a small amount of water vapor. If the engine is not burning properly, the exhaust gas will be mixed with incompletely burned carbon particles, hydrocarbons, carbon monoxide and a large amount of water vapor. In addition, there are also nitrogen oxides, etc., at which time the color of the exhaust gas may become black, blue or white, that is, the exhaust smoke is not normal. For gasoline engines, normal exhaust should have no visible fumes. However, when the lubricating oil is on the cylinder, the exhaust gas is blue; when the combustion is not complete, the exhaust gas is black, and when the oil is mixed with water, the exhaust gas is white.
4, overheating and high temperature
Usually appear on engines, transmissions, transaxle final drives, differentials and brakes. For example, if the engine is overheated, it is often a problem with the cooling system. It is lack of coolant or the pump does not work; the transmission and the drive axle are overheated, mostly due to lack of lubricating oil; the brake is overheated, mostly caused by the brake shoe not returning. The above phenomenon can sometimes be directly reflected by the warning light of the instrument panel. It is necessary for the driver to pay attention to the observation while driving, or to test the external temperature by hand.
Leakage refers to the seepage of fuel, lubricating oil (or gear oil), brake fluid (or compressed air) and power steering oil of automobile engines. Leakage phenomenon. This is also an obvious symptom of the malfunction, which can be found by careful observation. For example, when the compressed air leaks, the sound of the leak can be clearly heard.
6. Excessive fuel and lubrication consumption
Excessive fuel and lubricant consumption indicates that the vehicle’s technical condition has deteriorated and has caused a malfunction.
7, have a special smell
If the car is in operation, if there is a brake drag, clutch slip and other faults, it will emit the burnt smell of the friction plate; the engine overheats, the lubricating oil cylinder When burning, it will emit a special smell; when the circuit is short-circuited, the ground wire will burn when it is burnt.
8, the car looks abnormal
The car is parked on a flat field, check the shape, if there is a phenomenon of horizontal or vertical skew, it is abnormal appearance. The reasons are mostly the failure of the frame, the body, the suspension, the tires, etc., which will cause the direction of the vehicle to be unstable, the deviation, the shift of the center of gravity and the wheel “eat the tire” and other faults.