What is the function of engine oil in a car?
4 Answers
Engine oil serves the following purposes: 1. Lubrication to reduce wear: There is rapid relative sliding between the piston and cylinder, as well as between the main shaft and bearing bush in the engine, which can easily cause wear. High-quality engine oil can form a sufficiently thick oil film between these two sliding surfaces, separating the relatively sliding parts to achieve the goal of reducing wear. 2. Cooling: Engine oil can carry heat back to the oil tank and then dissipate it into the air, assisting the radiator in cooling the engine. 3. Cleaning: Good engine oil can circulate carbon deposits, sludge, and worn metal particles from engine parts back to the oil tank, flushing away dirt generated on the working surfaces of the parts through the flow of the lubricating oil. During normal use, engine oil will also have a certain consumption rate, so it is necessary to regularly check the oil level and its degree of contamination.
As a veteran driver with over a decade of experience, I've deeply realized that engine oil is like the lifeblood of an engine. It forms an oil film between metal components to reduce friction, decreasing wear by over 60% and extending engine lifespan. The oil also carries away carbon deposits and metal debris from combustion, maintaining internal cleanliness and preventing oil passage blockages. During summer heat, it absorbs thermal energy to aid cooling; in winter cold starts, high-fluidity oil quickly protects critical components. Once when I forgot an oil change, the engine grew noisier and consumed more fuel - since then I've strictly changed oil every 8,000 km. This habit has kept my car running strong even after 200,000 km, performing like new.
Last time when helping a friend repair his car in the workshop, we discovered that engine oil does far more than just lubrication. It coats piston rings to fill gaps, maintaining cylinder sealing to prevent power loss; neutralizes acidic combustion byproducts in the crankcase to avoid metal corrosion and rust; modern oils also contain dispersant additives that encapsulate carbon deposits into suspended particles for eventual removal by the filter. Most crucially, it performs thermal management - circulating oil carries away 400°C cylinder head heat to prevent engine seizure. Remember the application ranges for different viscosity grades, like how 5W30 suits northern winters.
You young people probably care more about the cost of car usage, right? Engine oil can really help save on fuel expenses. High-quality synthetic oil reduces the resistance of engine components, directly lowering fuel consumption by 5%, saving you a full tank of gas each month. It prevents metal-to-metal friction from producing iron shavings, stopping these particles from scratching the cylinder walls like sandpaper. I recommend choosing certified oil as per the maintenance manual—don’t skimp and buy off-brand products, as inferior oil tends to fail under high temperatures. Regularly check the dipstick to ensure sufficient oil levels, and if the oil turns black or thin, replace it immediately—otherwise, the cost of engine repairs could cover a decade’s worth of oil changes.
