What is the replacement interval for synthetic motor oil in cars?

[DeLawson]

The replacement interval for synthetic motor oil in cars is between 10,000 to 12,000 kilometers. The functions of motor oil are: 1. To reduce wear between the piston and cylinder, as well as between the main shaft and bearing bush, providing lubrication; 2. To assist in cooling the engine internally; 3. To clean carbon deposits, sludge, and metal particle impurities from engine components; 4. To minimize gas leakage and prevent external contaminants from entering; 5. To cushion and absorb shocks from the piston, piston chips, connecting rod, and crankshaft bearings; 6. To reduce frictional resistance, save energy consumption, and minimize wear. Excessive motor oil in a car can lead to: 1. Increased engine operating resistance, affecting engine power; 2. Carbon buildup or contamination of the three-way catalytic converter, reducing its conversion efficiency.