Why Does Engine Oil Turn Black After Being Changed?

[Shane]

Engine oil turns black after being changed primarily due to delayed oil replacement. The functions of engine oil include: 1. Reducing friction and high temperatures; 2. Minimizing gas leakage and preventing contamination from external pollutants; 3. Protecting components from contact with water, air, and acidic harmful gases; 4. Buffering the pressure rise in the engine cylinder ports; 5. Flushing away dirt generated on the surfaces of components. The steps for changing engine oil are: 1. Lift the vehicle and remove the underbody shield; 2. Place an oil container beneath the oil pan and loosen the drain plug; 3. After draining the oil, replace the oil filter and apply a layer of oil around it; 4. Tighten the drain plug, reinstall the shield, lower the vehicle, and pour in the new engine oil.