How often should a sedan change its engine oil?
3 Answers
Sedans should change mineral oil within 5,000 kilometers; semi-synthetic oil within 7,500 kilometers; and full-synthetic oil within 10,000 kilometers. Engine oil, motor oil, or engine lubricant is a substance enhanced with additives in base oil, mainly containing anti-wear additives, detergents, dispersants, and multi-grade viscosity index improvers. The primary functions of engine oil are to reduce friction and wear of moving parts, and to remove sludge (one function of dispersants) and varnish (detergents) from the engine. Engine oil also neutralizes acids produced from fuel and lubricant oxidation (detergents), improves the sealing of piston rings, and cools the engine by carrying away heat from moving parts.
Changing engine oil isn't a one-size-fits-all matter - it largely depends on your driving habits and the type of oil used. Mineral oil typically requires replacement every 5,000 kilometers or six months, while semi-synthetic oil can last about 7,500 kilometers. Full synthetic oil is the most convenient, capable of running up to 10,000 kilometers. During my last maintenance visit, the mechanic reminded me that frequent traffic congestion or mountain driving requires shorter oil change intervals. It's wise to develop a record-keeping habit - placing a reminder sticker on the windshield after each service helps prevent engine neglect. Nowadays, smartphone reminders make this process even more convenient.
Different cars have different requirements, so you need to check your car's manual. Some new car manuals say you can change it every 10,000 kilometers. My neighbor's old car needs an oil change every 5,000 kilometers, and he says if the engine sounds off, you should go right away. The weather also plays a role—like in our area, where summers are hot, the oil tends to degrade faster. The easiest way is to check the dashboard; if the maintenance light comes on, delaying for half a month is usually fine, but don't wait too long. You can also pull out the dipstick to check the oil color—if it's too black or sticky, it's time to consider a change.
