How often should the engine oil in a car be changed?
2 Answers
Engine oil in a car should be changed once a year. Engine oil, also known as motor oil or engine lubricant, is a substance enhanced with additives in a base oil, primarily containing anti-wear additives, detergents, dispersants, and multi-grade viscosity index improvers. Engine oil is used for lubricating internal combustion engines. Its main functions are to reduce friction and wear on moving parts, remove sludge (one of the functions of dispersants) and varnish (detergents) from the engine. It 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.
I've been driving for over 20 years, and oil changes shouldn't be generalized. Many people still stick to the old habit of changing every 5,000 kilometers, but with today's advanced engine designs, manuals usually recommend every 8,000 to 12,000 kilometers or once a year, depending on the oil type—mineral oil requires more frequent changes, while full synthetic oil lasts longer. I prefer adjusting based on driving conditions: if you're often stuck in city traffic with lots of short trips, the engine tends to accumulate more contaminants, so you might need to change it earlier, around 6,000 kilometers. For highway driving, where the oil stays cleaner, you can wait longer. I regularly check the dipstick myself—after parking for half an hour, I pull it out, wipe it clean, and ensure the oil level is between the min and max marks. If the oil turns black or looks cloudy, I change it immediately. This approach protects the engine without wasting money on unnecessary oil changes. It saves you from costly engine repairs down the road.
