What Causes Internal Engine Noise?

[DelLucas]

Reasons for internal engine noise: It could be due to loose screws on the engine underguard or loose plastic parts in the engine compartment, which can be fixed by tightening; or it might be caused by aging engine mounts, which support the engine and can only be replaced in such cases. Under normal conditions, when the engine is idling, only a uniform and slight exhaust sound should be audible. Engine noises can be categorized by location into main engine noise and accessory noise. If the noise disappears after loosening the fan belt, it indicates the noise is related to the water pump, generator, or their rotating components. If the noise stops after loosening the air compressor belt, then the noise is from the air compressor or its related components. If the noise persists after loosening all drive belts, the issue is likely with the main engine.

[SophiaFitz]

There's a strange noise inside the engine, which I encounter most frequently. It could be an issue with the valve train, such as loose adjustment screws or insufficient spring tension, causing metallic knocking sounds. Or it might be bearing wear, like increased friction from worn crankshaft or small end of connecting rod bearings, producing a low rumbling noise. Insufficient lubrication is also a common cause; too little or degraded engine oil leads to obvious dry friction noises from components. Another possibility is a loose timing chain, which creates a rustling sound when slipping. My advice is to stop and check the oil level and color immediately upon hearing abnormal noises. If the oil level is fine, it might be internal component looseness. Never ignore it—delaying can lead to more severe damage, like when I delayed repairs last time and ended up spending a fortune on bearing repairs. Regular maintenance can prevent issues; changing the oil every 5,000 kilometers is crucial, and using the right lubricant extends component lifespan.

[DeAutumn]

In the garage, I've seen many cases of abnormal noises. Typically, incorrect valve clearance produces a noticeable ticking sound. Bearing damage is also common, with different sounds depending on the location; for instance, the crankshaft area produces a dull thud. When oil quality is poor or insufficient, friction noises from the piston pin or other moving parts become loud. The abnormal sounds from chains and belts are relatively easy to distinguish—looseness results in a rustling noise. I always remind friends to diagnose issues early; repair costs are lower when the noise is minor, but they escalate when the problem worsens. For prevention, it's crucial to check the engine oil level monthly and avoid high-speed driving on dirt roads to minimize dust ingress. Internal abnormal noises may also stem from aging components, making timely replacement with genuine parts essential. Remember, minor noises can indicate significant risks, so it's best to use professional tools to pinpoint the issue.

[McHailey]

Engine abnormal noise poses a high safety risk, which is truly unsettling. For example, if bearing wear isn't repaired, it may cause engine seizure - sudden stalling while driving is extremely dangerous. Valve problems produce clicking sounds, and prolonged neglect affects acceleration capability. Insufficient lubrication causes friction noise, and continued driving may lead to bearing bush burnout. I once experienced abnormal noise on the highway and ignored it, nearly causing an accident. Therefore, it's crucial to stop immediately for inspection - safety first. Most abnormal noises result from loose or worn internal components, so early diagnosis can avoid major repairs. Developing the habit of listening for sounds before starting the engine can reduce potential threats.