What Causes the Squeaking Noise When Starting the Car?

[DiKeegan]

There are several reasons for the squeaking noise when starting the car: 1. If the car has not been used for a while, the engine oil will flow back to the oil pan, resulting in insufficient oil in the top part of the engine, such as the valve chamber. Since the valves lack the sealing and lubrication from the oil, a hissing sound can be heard from the bottom of the car when starting it. This situation is normal. 2. A continuous hissing sound after starting the car is most likely due to an issue with the engine belt. First, check the tightness of the engine belt. You can try pinching the belt with your fingers and twisting it. Note that this operation should be performed when the engine is cool. The twisting angle should generally be less than 90 degrees; otherwise, an adjustment is needed. 3. The noise from the engine belt can also be caused by dirt accumulation. Cleaning it with water or applying some lubricant can eliminate the noise.

[LaLiam]

I've been driving for many years, and squeaking sounds during startup are quite common, usually caused by issues in the belt system. For example, the alternator belt, A/C belt, or fan belt might be loose or worn out, as they can slip and make noise when they shrink; it could also be a bearing problem, like insufficient lubrication or failure of the water pump bearing, which is more noticeable when the engine is cold. Additionally, faults in the A/C compressor or tensioner pulley can produce similar sounds. Although the noise might seem minor, don’t underestimate it—ignoring it could lead to belt breakage, engine overheating, and even being stranded on the road. After parking, I recommend visually inspecting the belts for cracks or looseness first, then starting the engine to identify the source of the sound. It’s best to visit a professional shop for diagnosis as soon as possible to prevent the issue from worsening. Regular maintenance, such as checking belt tension and axle lubrication every six months, can significantly reduce such occurrences.

[MacSimon]

As an ordinary car owner, I've also encountered the issue of squeaky noises during startup. I noticed these sounds mostly come from the front of the engine, likely from the belt area - aging alternator belts often cause this, especially on humid days. Loose fan belts or AC compressor belts can also produce squeaking sounds. Don't rush to spend money on repairs; try some simple troubleshooting first: open the hood and have a friend help locate the general source of the noise during startup. If it's a belt issue, spray some water on it - if the noise disappears, the belt is loose. If the sound persists, it might be a bearing problem, such as wear in the water pump or fan bearings. I recommend getting it checked soon to avoid compromising driving safety. During maintenance, pay attention to belt replacement intervals - generally consider replacing them around 50,000 kilometers to prevent such issues.

[Zara]

Squeaking noises are most common during startup, often caused by aging belts or tensioner pulley failure. Worn or loose belts can slip and make noise; seized or dry tensioner pulleys can also cause abnormal sounds. I've tried this inspection method: spray water on the belt surface at startup—if the noise stops, it's likely looseness; if it continues, the issue may be with the steering bearing or AC compressor. Don't ignore this to avoid engine overheating or breakdown. Simple maintenance like regularly cleaning belt pulley grooves and replacing low-quality belts can effectively reduce noise. Pay attention to abnormal sounds while driving daily and address them early.

[MiguelAnn]

The squealing sound during startup may seem harmless, but it carries significant potential risks. I've witnessed cases where it led to belt breakage and engine overheating failures. The primary causes lie in loose or worn belt systems, such as the alternator belt, or damaged bearings like the water pump bearing, fan malfunctions, or insufficient lubrication. The issue becomes more pronounced when the AC compressor is engaged. For safety, inspect the belt condition before cold starts—check for cracks or excessive looseness. If the noise occurs frequently or persistently, immediately consult a technician for electrical circuit and component diagnostics using specialized tools. Ignoring it could damage more components; develop a monthly inspection habit, and replacing belts contributes to long-term stability.

[VonLeo]

Squeaking noises are more common during cold starts, and I often pay attention to this issue. Insufficient belt tension or contamination are the main causes—loose alternator belts grinding the edges or fan belts slipping due to oil can cause squeaking; bearings such as water pump or fan bearings lacking lubrication or aging can also produce such sounds. The issue is more likely to occur when the AC compressor is turned on or off. It is recommended to regularly lubricate the wheel shafts during maintenance and ensure proper belt tension; conducting a check every six months can reduce faults. Avoid dust entering components and keep the engine area clean; if abnormal noises appear, do not delay, address them early to prevent minor issues from becoming major problems. Replacing belts or bearings is not expensive, but delays could damage the engine.