What happens if engine oil is changed late?
2 Answers
Delayed oil change can lead to: 1. Deposited impurities corroding internal engine components; 2. Increased sludge formation, making it difficult for the oil pump to maintain pressure and potentially causing engine failure; 3. Oil degradation and ineffectiveness, reducing its lubrication and protection capabilities and accelerating component wear; 4. Oil thinning, losing its sealing properties and leading to gas leakage; 5. Reduced cooling performance. Engine oil, also known as motor lubricant, serves multiple functions including lubrication and friction reduction, auxiliary cooling, sealing against leaks, rust and corrosion prevention, and shock absorption. It consists of base oil and additives, with the base oil being the primary component that determines the fundamental properties of the lubricant.
I used to be a careless person, always forgetting things. Delaying oil changes is really bad. That time I postponed it for two months, and the engine started making clanking noises with a significant drop in power. When I took it for inspection, the oil had turned into black sludge, full of metal shavings and dirt, losing all its lubricating effect. The bearings and pistons were severely worn, and the repair cost nearly two thousand yuan. The mechanic said engine oil is like protective fluid—once expired, it thins and becomes acidic, corroding internal engine parts. Over time, the entire engine could seize. Now I don’t dare slack off—I check the odometer every month and change the oil promptly at 5,000 km, replacing the oil filter too, as a clogged one would be even worse. Daily driving also suffers—more noise and a fuel consumption increase of about 0.5 liters, making early oil changes more cost-effective in the long run. In short, delaying oil changes invites trouble—minor repairs at best, or a full engine replacement at worst. The risk is just too high.
