What is the normal sound of engine idling?

[DeArianna]

Normally, during the engine startup process, there should be no screeching sounds, and the engine idling sound should be even. When starting a cold engine, there might be a ticking sound, which weakens and disappears after the engine warms up. This is considered normal engine sound. The reasons for an increase in car engine noise are as follows: 1. Engine abnormal noise: The engine makes a tapping sound, similar to a pencil knocking on a table, and the sound increases as the engine speed increases. Possible causes include impurities inside the engine. It is recommended to change the engine oil, oil filter, and clean the engine. 2. Inability to increase speed: While driving, acceleration may be normal, and ignition might also be normal. However, if you notice that the engine speed is too high but the speed still doesn't increase when driving at a constant speed, try checking the coolant. If the oil pressure is too high or too low, check the oil pressure gauge. There might also be an issue with the ignition timing settings, which could lead to such symptoms. Other possible causes include internal engine problems, such as a clogged EGR valve.