The car engine noise not only makes the driver feel annoyed, but also may be a precursor to the car's problems.   1. Cold start The engine will vibrate and produce a "beep" noise when the car starts after parked for a long time. Because the lubricant basically flows to the oil sump after parking for a long time, the oil pump can not establish the oil pressure immediately when the cold car starts, especially the valve inside the cylinder head , which is not enough lubricated. The hydraulic tappet and the mechanical rocker arm failed to work properly, causing a squeaking sound. Solution: The noise is normal under this situation. When the engine is started for a while, it will work normally and there will be no more noise.   2. Poor engine oil condition Engine oil is an important component of engine lubrication. When the oil is in trouble, it will affect the working condition of the engine. When the viscosity of the oil is too high and the lubrication is deteriorated, it is easy to cause friction during the operation of the engine, thereby generating noise. Solution: Faced with this situation, you only need to flush and replace the engine oil.     3. Belt tightness When the engine belt is not tight enough, the engine will produce sharp noise during work, which seriously affects the driver's driving experience. Solution: Faced with this situation, it can avoid noise adjusting the tightness of the engine belt.   4. Intake and exhaust pipe leaks IF there is a leak in the intake and exhaust pipe, the gas leaks from the leak, it will cause vibration and noise when the engine is started Solution: Faced with this situation, it is necessary to check the intake and exhaust pipe, and replace the intake and exhaust pipes to avoid noise.   5. Poor fuel quality When poor quality fuel is used, the combustion inside the engine will be worse, causing the engine to vibrate and make noise. Solution: Faced with this situation, you can avoid noise by replacing the better quality fuel with higher number.   6 . Engine abnormal noise The engine can not be fixed when engine under guard plate screws are loose, and it will shake vigorously during work, generating noise. This is a relatively common glitch, tighten or adjust the engine under guard plate screws can fix it. The engine jaw pad is aged. The claw pad plays the role of supporting the engine. When it is aged, it can't play normal work. At this time, it can't be repaired, only the new claw pad can be replaced. Engine "tempering" failure. When the engine's valve carbon is accumulated too much or the timing is not adjusted properly, the engine will have a "beep" sound. At this time, the valve carbon is cleaned and the valve timing is adjusted.   These are the main reasons for the high noise of the engine and possible solutions. When there is a problem with the car, it is recommended that the owner solve the problem immediately, so as not to accumulate a large fault. It is not only unsafe to drive, but also uncomfortable.