What are the methods to determine when engine oil needs to be changed?

[LaAva]

Engine oil needs to be changed based on the following methods: 1. Check the quality of the oil—if it appears black in color and has an unusual odor; 2. Inspect the viscosity of the oil; 3. Use an oil test paper—place a drop of oil on the paper and leave it overnight. If the edges between the oil ring, sediment ring, and diffusion ring harden, it indicates the oil needs changing. The functions of engine oil are: 1. Lubrication to reduce wear; 2. Transferring heat back to the oil tank and then dissipating it into the air to help the radiator cool the engine; 3. Forming a seal between the piston rings and pistons through an oil film to prevent combustion gases from entering the crankcase; 4. Rust and corrosion prevention; 5. Shock absorption and cushioning; 6. Cleaning dirt from the surfaces of components.

[LaWyatt]

To determine if the engine oil needs to be changed, the recommended intervals in the vehicle manual are crucial. It's advised to check every 5,000 to 10,000 kilometers. After driving, I often pull out the dipstick to see if the oil level is within the marked range, topping up or changing if it's low. The color of the oil is a big clue—fresh oil is amber, and if it turns black or appears cloudy, it's dirty and needs changing. Dipping a finger in the oil and rubbing it can help gauge its viscosity; if it's too thin or too thick, it's not ideal. Before long trips or frequent short drives, I change the oil in advance to reduce engine wear. Regular oil changes also save money and extend the car's lifespan—never delay until problems arise.

[LaLyla]

Decades of driving experience have taught me that oil condition can be judged by feel and sight. When you pull out the dipstick for a close look, if the oil stain turns dark brown or black, especially with metal shavings or impurities sticking to it, that's a sign of aging and the oil needs to be changed immediately. Normally, by touching the oil, if it feels as thin as water or too thick without elasticity, it indicates poor lubrication. After driving in dusty areas, the oil gets dirty quickly from absorbing dust, so I deal with it in advance. When engine noise increases, you also need to be alert to oil problems to avoid major repairs.

[LylaFitz]

I enjoy checking the engine oil myself using those specialized oil test strips—simple and accurate. Just dip a bit of oil on the paper, wait a few minutes, and observe the spread of the oil stain; if the color darkens with a large black spot in the center, it's a sign it needs changing. I also replace the oil if the level drops below the minimum mark or if the oil appears cloudy. Changing the oil is something I can handle on my own, saving on repair shop costs while picking up some maintenance knowledge. Engine health is paramount—old oil affects performance, so occasionally topping up with fresh oil to test the results helps.