What Are the Causes of Engine Idling Noise?
2 Answers
Excessive clearance, engine misfire, and engine knocking are all causes of abnormal noise during engine idling. The details are as follows: 1. Abnormal noise caused by excessive clearance. Clearance is a critical factor in automotive assembly quality. When lubrication, temperature, load, and speed are constant, the noise becomes more noticeable as the clearance increases. Some engine components may produce noise due to wear-induced excessive clearance. 2. Engine misfire noise. Engine misfire mainly refers to one or more cylinders not functioning properly, manifested as intermittent exhaust gas flow and severe shaking of the exhaust pipe, accompanied by clear "popping" or thumping sounds from the engine.
With years of experience in car repair, I've encountered many cases of strange noises during engine idling. The most common issue is loose or aged belts, which produce squealing or rattling sounds, especially in older vehicles. If the water pump bearings are worn out, they can also create a continuous tapping noise, and if not repaired promptly, the engine temperature can rise easily. Additionally, when the engine oil is too thin or insufficient, increased engine friction can lead to metal scraping sounds. Don't overlook spark plug problems either; poor ignition can cause the engine to hum and shake. I recommend car owners regularly check the belt tension and oil condition, as a small adjustment can prevent major troubles. When you hear unusual noises while parked, don't rush to drive off. Try turning off the air conditioning or fan to rule out whether auxiliary components are the culprits.
