How to Determine When to Change Engine Oil?

[DelJayla]

Methods to determine when to change engine oil are: 1. Check the oil quality—if it appears black in color and has a sour smell, it needs to be changed; 2. Use your finger to check if the oil still has viscosity; 3. Difficulty in shifting gears when starting the car cold. The steps to change engine oil are: 1. Remove the air filter, clean it using an air pump, and reinstall it; 2. Lift the car, unscrew the drain plug to drain the oil, and remove the oil filter; 3. Add approximately 3.5 liters of new engine oil. The functions of engine oil are: 1. Reduce friction and high temperatures; 2. Cool and lower temperatures; 3. Clean and remove contaminants; 4. Absorb shocks and cushion impacts; 5. Prevent rust and corrosion.