When Should Engine Oil Be Replaced Based on Its Remaining Life?

[HavenAnn]

Engine oil should be replaced when its remaining life falls below 20%. However, this should also be determined based on the settings of the vehicle's onboard computer. When the onboard computer is properly configured, it will issue a reminder once the engine oil's service life reaches the replacement threshold. It is recommended that car owners replace the oil promptly to prevent abnormal engine wear during driving, which could affect normal operation and shorten the engine's lifespan. Precautions for oil replacement: 1. Choose engine oil according to the engine's requirements. Do not use high-grade oil in a low-performance engine or low-grade oil in a high-performance engine. Select oil that matches the engine specifications. 2. Opt for multi-grade oil, which offers advantages such as fuel efficiency, extended service life, and high performance, providing better protection for the engine. 3. The oil level should be slightly below the mark on the dipstick; avoid overfilling. 4. Select oil with different viscosities based on the engine's operating conditions. 5. If switching from premium or mid-grade oil to regular oil, first drain all the existing oil and thoroughly clean the lubrication system to prevent mixing.

[TuckerRose]

I drive quite frequently and often need to change the engine oil. When the oil life indicator shows around 15%, it's time to consider changing it—don't wait until it hits 0%. Driving habits significantly impact the oil's condition. If you frequently take short trips or idle in traffic, the engine temperature may not rise sufficiently, preventing moisture in the oil from evaporating, which can lead to faster deterioration. I usually change the oil a bit earlier, especially during hot summer weather when oil oxidizes more quickly. Full synthetic oil can last 8,000–10,000 km, while mineral oil needs replacement every 5,000 km. Once, after a long highway trip, the dashboard showed 20% oil life remaining, but the drained oil was already black, proving that computer estimates aren’t as reliable as actual inspections. I recommend monitoring both mileage and oil life indicators. The maintenance manual suggests changing every six months or 5,000 km, but full synthetic can last up to eight months or 7,500 km.

[DiNova]

My personal car comes with an electronic oil life monitoring system, and I can see the percentage drop every time I start the engine. I usually schedule a service at the dealership when it falls below 20%, as engine oil doesn't just lubricate—it also helps cool the engine and clean carbon deposits. Depending on usage: for drivers who frequently make short trips in the city, it's recommended to change the oil every 5,000 kilometers or six months; those who drive more on highways can extend it to 7,500 kilometers. An important tip is to consider the number of cold starts—repeated cold starts are the most damaging to engine oil, as they can mix with gasoline and reduce viscosity. Once, I left my car unused for three months while on a business trip, and when I returned, the oil life was still at 30%, but I changed it anyway because oil can absorb moisture and emulsify over time. Modern car systems can now calculate the number of start-stop cycles and engine load, making them much more accurate than the old mileage-based methods.

[VanHazel]

I've noticed many car owners only focus on the percentage displayed on the dashboard, but a comprehensive judgment is actually needed. For example, after the last maintenance, the car has run 7,000 kilometers with only 10% oil life remaining. When pulling out the dipstick, there's a burnt smell, and the oil film shows cracks. The five main functions of engine oil are lubrication, cleaning, sealing, rust prevention, and cooling. Signs of oil failure include increased metal debris and decreased viscosity. Modified cars or turbocharged engines require earlier oil changes as high temperature and pressure environments accelerate oil degradation. Experienced drivers also check the exhaust – blue smoke indicates oil failure. It's recommended to change mineral oil within 5,000 kilometers, semi-synthetic within 6,000, and full-synthetic within 8,000, but never exceed one year regardless of mileage.