Is it necessary to change engine oil every year?
2 Answers
Engine oil does not necessarily need to be changed if it has been over a year, and you can still drive temporarily. However, it is important to promptly visit a qualified maintenance facility to replace the engine oil and oil filter to prevent the degradation of its lubrication, cooling, sealing, and cleaning functions, which could cause engine damage. Below is a detailed introduction to the functions of engine oil: 1. Lubrication: Dry friction between metal surfaces can cause scratches, so the lubricating effect of engine oil is needed for protection. With the lubrication of engine oil, metal parts do not directly contact each other but float on the oil film. This is often referred to as the "oil film bearing" effect. 2. Cleaning: After prolonged engine operation, metal burrs may inevitably fall off due to friction. These burrs could potentially damage other metal surfaces. Therefore, engine oil's flushing action is essential to "carry away" these metal burrs. 3. Cooling: The engine operates at high temperatures internally, and while the cylinders rely on the cooling system, certain internal components cannot be cooled by it and instead depend on the circulation of engine oil to dissipate heat. 4. Rust prevention: Additionally, engine oil isolates metal surfaces from air, ensuring that internal engine metals do not oxidize or rust.
As an ordinary car owner who commutes daily, I've encountered similar confusion. In fact, the oil change interval depends on specific usage conditions, not simply calculated by one year. Based on my experience, for urban commuter cars using mineral oil, it's indeed recommended to change every six months or 5,000 kilometers. After I switched to full synthetic oil, the 4S shop said it could last up to one year or 10,000 kilometers. During my last maintenance, I specifically observed the drained oil - it remained transparent even after over 10 months. Of course, actual driving conditions must be considered too - my neighbor only drives 3 kilometers daily for grocery shopping, making the oil more prone to emulsification and deterioration. For such short-distance usage, it needs changing every six months.
