Can the engine oil still be used when its remaining life is 20%?
2 Answers
Engine oil with 20% remaining life can still be used. Oil life refers to the service life of the oil, meaning that when the oil life reaches 0%, the viscosity and performance of the oil deteriorate, making it ineffective, rather than indicating there is no oil left. An oil life of 20% means the current performance of the oil is 20% of that of new oil. After an oil change, the oil life is 100%. Over time or with increasing mileage, the oil life gradually decreases. Generally, when it reaches 10%, the vehicle's dashboard will display a reminder for maintenance, indicating the need for an oil change. Since the percentage of oil life is estimated based on the oil change interval, the intervals for mineral oil, semi-synthetic oil, and full synthetic oil differ. Thus, the same oil life percentage implies varying remaining usable time and mileage. For example, when using mineral oil with 20% oil life remaining, it may indicate about 1,000 kilometers until the next oil change. However, with full synthetic oil, the same 20% oil life could mean 2,000 kilometers until the next change. Therefore, questions like "How long can I drive with 10% oil life?" require estimation based on the type of oil used. If the vehicle prompts for maintenance, it should be addressed promptly. After maintenance, the oil life should be reset to 100%.
When I see the oil life remaining at 20%, I always wonder if I can hold off until the weekend to change it. In reality, this percentage is estimated based on driving habits and mileage, reminding you that the oil's performance is declining but hasn't completely failed yet. So, driving short distances to work or the grocery store is perfectly fine. I've driven my sports car multiple times in this condition, and the oil film protection still works effectively without immediately damaging the engine. However, delaying the oil change for too long can lead to sludge buildup and increased friction, which not only raises fuel consumption but also makes the engine prone to overheating issues. The best practice is to quickly check the dipstick, confirm the oil level is normal, and schedule a change within the next few hundred kilometers. After all, engine repairs are much more expensive than an oil change—better to act a bit early than panic when the warning light comes on.
