Why does the engine make a buzzing noise at idle that disappears when accelerating?
2 Answers
The reason for the buzzing noise at idle that disappears when accelerating is: lack of engine oil. The noise disappearing when accelerating may indicate the engine is burning oil, so the oil level should be checked regularly. Idle is an operating condition of a car, referring to the engine running in neutral gear. The engine speed at idle is called the idle speed, which can be adjusted by changing the throttle opening size, etc. The reasons for the buzzing noise at idle in a car engine are: 1. Excessive carbon deposits in the engine, throttle, and spark plugs; 2. Dirty air filter; 3. Dirty or substandard engine oil; 4. Worn or damaged universal joint of the driveshaft due to lack of lubrication; 5. Damaged engine mounts; 6. Abnormal cylinder pressure.
I've also encountered this idling buzzing noise issue. I remember when the car was stationary, the engine area kept buzzing, which was quite annoying, but the sound disappeared when I stepped on the accelerator. This is likely a problem with the belt system, such as a loose or aged belt tensioner. At idle, the loose belt vibrates and buzzes, and the noise disappears when the belt tightens upon acceleration. Alternatively, it could be worn bearings in the generator or air conditioning compressor. At idle, the small load makes the bearing friction noise obvious, while acceleration vibrations mask the sound. Another possibility is loose brackets or mounting screws, causing the engine to shake and make noise at idle, while smoother motion during acceleration reduces the noise. Don't underestimate this issue; delaying repairs could damage other components, such as a broken belt affecting battery charging. It's best to visit a professional shop as soon as possible to check the belt condition and bearings. Regularly cleaning dust from the engine compartment during car washes can also help prevent such problems.
