Why is there a buzzing sound after starting the car?
3 Answers
Reasons for the buzzing sound after starting the car: 1. If the car hasn't been used for a while, the engine oil will return to the oil pan, causing the valve chamber to burn oil. Due to the lack of oil sealing and lubrication in the valve chamber, you may hear a buzzing sound from the bottom of the car when starting it. This situation is normal. 2. Check the tightness of the engine belt. You can try pinching the drive belt with your fingers and twisting it, ensuring the twist angle is below 90 degrees. 3. Loose engine mount bolts causing improper engine support installation. 4. Foreign objects obstructing the engine compartment. 5. A dirty engine belt causing the buzzing sound. Cleaning it with water or using some lubricant can eliminate the noise.
I've been driving for many years and have encountered squealing noises quite often, usually indicating an issue with the belt system. When starting the car, if the belt is old or loose, it can slip on the pulleys, producing that characteristic squealing sound, commonly seen in the alternator or air conditioning compressor drive belts. Sometimes, temperature changes can also cause uneven belt tension, which may improve after driving for a while, but prolonged exposure can accelerate wear on components. I recommend first opening the hood and using a stethoscope or gently touching the belt to see if it's loose. If the noise continues to worsen, don't ignore it—promptly visit a reliable auto repair shop to check the belt's condition and pulley bearings. Replacing a new belt only costs a few dozen dollars and can prevent more serious failures like engine stalling. During regular maintenance, ask the mechanic to adjust the belt tension. Checking it once or twice a year can prevent problems before they occur, saving you hassle, money, and ensuring safety.
When I do DIY car repairs, I often get nervous hearing that hissing sound, only to find out it's mostly caused by electrical component friction - it could be the generator bearing making noise due to lack of oil during cold starts, or sparking sounds from oxidized starter cable connections. I remember one cold winter day when the car would hiss as soon as it moved, and it turned out to be static noise from loose battery cables. If left untreated, these small sounds can escalate into major failures, like a broken generator causing the car to stall midway. I make it a habit to regularly clean these connections and use a multimeter to check current stability. For beginners, I'd suggest checking the manual first - sometimes simply tightening screws might help. If the noise comes with vibrations, it's best to visit a professional shop. A small repair can restore quiet driving and peace of mind.
