What Causes Loud Engine Noise During Startup?
3 Answers
The loud noise during engine startup is primarily caused by excessive engine oil, which increases the stirring resistance of the crankshaft connecting rod, leading to amplified noise. Below are extended details regarding oil changes: Changing Engine Oil and Oil Filter: It is essential to change the engine oil promptly during vehicle maintenance. If the oil turns black, becomes thin, or contains sand particles, usage should be discontinued immediately. Prolonged use of unchanged or deteriorated oil not only fails to provide lubrication but also damages the engine. It is advisable to replace the oil filter simultaneously during an oil change to prevent contaminants from the old filter from compromising the quality of the new oil. Considerations for Selecting Engine Oil: When selecting engine oil, opt for lower viscosity grades. Low-viscosity oils offer better fluidity, effectively reducing engine wear. Engine oil functions as hydraulic fluid within the hydraulic lifters. Given the engine's high rotational speed, the frequency of oil flowing in and out of the hydraulic lifters is also very high. When the oil viscosity is too high, it results in insufficient oil intake per cycle, causing delayed hydraulic lifter response. This leads to inadequate extension of the pushrods, increased valve clearance, and consequently, valve noise.
I find that loud car starting sounds are quite common, especially in cold weather. The engine oil becomes thick and difficult to flow, reducing lubrication effectiveness, which leads to increased friction noise during startup, making a roaring sound. Additionally, aging of the starter is another factor. After several years of use, its gears may wear out or rust, reducing rotation efficiency and producing harsh noises. In some cases, the exhaust pipe joint may become loose or cracked, allowing exhaust gases to leak out and amplify the sound. Regular maintenance is essential, such as changing the oil periodically to avoid excessive strain during cold starts after long periods of parking in winter. If the noise is particularly persistent or occurs even in warm weather, it’s best to promptly visit a repair shop for inspection to prevent minor issues from escalating into major faults. This not only ensures quieter driving but also extends the vehicle’s lifespan, saving on future repair costs.
I've driven quite a few cars, and loud starting noises are often a sign of abnormality, especially in the starter system. Short circuits in the motor coils or lack of lubrication in the bearings can cause a loud buzzing sound, resembling a tractor starting. Sometimes, rusted and perforated exhaust pipes can lead to high-speed gas leaks, creating explosive noises, which are more noticeable in summer. Another possibility is excessive carbon buildup inside the engine, causing rough piston movement, which worsens the noise during cold starts in winter. It's advisable to investigate promptly. First, listen to identify the source of the noise. If it's from the front lower area, it's likely a starter issue; if it's from the rear, the exhaust pipe might be damaged. Address this problem early to prevent safety risks—breaking down halfway would be troublesome. Just find a reliable repair shop for a proper diagnosis and fix, and don't delay.
