What Causes the Sizzling Sound During Cold Start of a Car?

[RobertLynn]

There are mainly three reasons for abnormal sounds during cold start of a car: 1. Poor combustion: When the car does not provide sufficient power, it may produce abnormal sounds. 2. Low ignition energy leading to abnormal sounds: The first issue a car faces during cold start is low temperature. The temperature inside the engine is insufficient, and both the fuel and lubricating oil are not warm enough. Therefore, more fuel should be injected during cold start to meet the power requirements. 3. Poor fuel atomization at low temperatures: Fuel requires higher ignition energy. After prolonged use, the ignition gap of the spark plug increases, leading to a decrease in ignition energy, which affects the power performance and causes the car to produce abnormal sounds.

[LeBrady]

A hissing sound during cold starts is something I've encountered many times as a veteran driver with over a decade of experience. The common causes are a loose or aged alternator belt or air conditioning belt. When the engine first starts, the cold belt hardens and creates friction against the pulleys, resulting in a hissing noise. If ignored, the belt may snap, causing the alternator to stop working or the battery to drain quickly, which can lead to a dangerous breakdown on the road. For a quick self-check: pop the hood and observe if the belt slips during a cold start. If you notice cracks, replace it immediately. Other possibilities include worn bearings in the tensioner pulley, which produce a sharper sound and require professional adjustment. Remember to have a technician inspect the belt condition during regular maintenance—typically replaced every 50,000 kilometers or so. Don't skimp on this small expense; safety comes first.

[MacHeidi]

A slight squealing noise during cold starts is quite common, likely caused by issues with accessory belt systems. Rubber components like the alternator belt or A/C compressor belt harden and wear over time, causing friction noise due to insufficient tension during initial startup. It could also stem from aging tensioner pulleys or bearings, where winter contraction worsens irregular rotation noises. To pinpoint the source, carefully listen near the noise location after ignition - adjust tension or replace belts if needed; use specialized tools for bearing repairs. Pay extra attention to abnormal sounds before long-distance or high-speed driving, as neglect may accelerate component wear or even affect the engine cooling system. We recommend inspecting these during routine maintenance using reliable parts for prevention.

[VonEmerson]

The car makes a squealing noise during cold starts, and I think it's mostly caused by a loose or worn-out belt. As an ordinary user, I've encountered this several times. The sound resembles friction, which occurs because the alternator belt has poor elasticity at low temperatures and slips on the pulley, causing noise. Checking it isn't difficult: open the engine hood during startup and see if the belt has cracks or appears shiny. If so, it means it needs replacement. Worn bearings could also cause noise, but belt issues are more common. A cost-effective solution is to tighten the tensioner yourself. Don't ignore it, as a broken belt could damage other components, leading to more expensive repairs. If unsure how to fix it, take the car to a repair shop promptly. They can quickly handle minor issues, which is better than delaying.