
Loud valve noise in a car is related to engine oil, and the reasons are: 1. Insufficient engine oil: When the oil level drops to a certain extent, air enters the hydraulic lifters through the oil passages, creating gaps that cause valve noise; 2. Air entering the oil passages during oil change: When draining the oil, the oil in the passages is emptied, and air enters. When starting the engine, air may enter the hydraulic lifters, causing valve noise; 3. During engine operation, oil circulates in the hydraulic lifters. If sludge forms in the engine, it can clog the oil passages, causing the hydraulic lifters' automatic gap adjustment function to fail, resulting in valve noise; 4. If the engine is severely worn, using oil with low viscosity can also cause valve noise.

I've been working on cars for many years and have encountered quite a few valve noise issues. Engine oil is definitely one of the key factors. The valve train, including lifters and rocker arms, requires oil for lubrication to reduce friction. If the oil level is low, too old, or has the wrong viscosity, the hydraulic lifters won't function properly, causing increased clearance and that annoying tapping sound. However, oil isn't the only culprit—worn valves, improper valve clearance, or aging of other engine components can also cause noise. I recommend first checking the dipstick to see if the oil level and color are normal. If the oil is black or has a burnt smell, change it immediately with fresh oil. In most cases, switching to a better-quality oil like 5W-30 or 10W-40, suitable for your car model, can help. But if the noise persists, it's best to take it to a repair shop for a thorough inspection of the valve clearance and other components. Addressing it early prevents minor issues from turning into major problems.

Having driven for decades and changed engine oil numerous times, I've found that increased valve noise is directly linked to oil quality. Good oil acts like a guardian, lubricating valve lifters and spring components; inferior oil or untimely changes lead to dry friction and clattering sounds. My previous car developed valve noise due to aged oil losing viscosity, but it quieted down significantly after an oil change. However, don't just blame the oil—excessive valve clearance or a loose timing chain can also be culprits. In routine maintenance, I make it a habit to check the dipstick monthly for oil level and change it every 5,000 km or so, opting for major-brand synthetic oils to prolong engine life. Neglecting oil issues may accelerate valve wear and shorten engine lifespan, with costly repairs. If noise only occurs during cold starts and fades, it's less concerning, but persistent rattling warrants inspection.

As an ordinary car owner, I've experienced the annoyance of loud valve noise, which could indeed be related to engine oil. When the oil level is insufficient or of low quality, inadequate lubrication increases friction in the valve mechanism, resulting in a tapping sound. Try checking if the oil level is within the proper range - if it's too low, top it up or switch to a higher-grade oil, which often improves the noise quickly. Also, check if the valve clearance needs adjustment or shows signs of wear. Address these issues promptly to prevent engine damage.

I usually pay attention to car maintenance, and increased valve noise is indeed often caused by engine oil. Engine oil acts like a lubricant for gears; if its viscosity is too low or it deteriorates under high temperatures, it cannot effectively coat the valve components, leading to knocking sounds. Choosing the viscosity recommended by the manufacturer, such as 0W-20, can effectively reduce noise, but note that this is not the only reason; valve design or external factors must also be considered. Regularly checking the condition of the engine oil is key to prevention.


