Why is it necessary to change engine oil during maintenance?
3 Answers
Maintenance requires changing the engine oil: Engine oil is extremely important for the engine, containing various additives that effectively protect the engine's critical components and ensure its normal operation. Its primary functions include lubrication, cleaning, rust prevention, sealing, and cooling, earning it the reputation as the 'blood' of a car. Engine oil consists of two parts: base oil and additives. The base oil is the main component, determining the oil's fundamental properties, while additives compensate for and improve any shortcomings in the base oil's performance, imparting certain new characteristics, making them an essential part of engine oil. Engine oil forms a protective film on the metal surfaces of the engine, reducing wear and tear on metal parts. It also breaks down sludge and deposits generated during engine operation, maintaining internal cleanliness. Additionally, it neutralizes acidic substances produced during engine use and forms a rust and corrosion prevention layer, preventing metal parts from oxidizing and corroding.
I remember during my last maintenance visit, the mechanic told me that engine oil works hard inside the engine every day. Over time, it becomes thick and sticky, full of metal shavings and carbon deposits. In a new car, after just 3,000 to 5,000 kilometers, the oil turns as black as ink. If you don't change it at this point, those contaminants will act like sandpaper, wearing down the engine. This is especially true during long summer drives when the engine temperature soars above 100 degrees Celsius—aged oil simply can't withstand such high temperatures. Moreover, modern engine oils contain special additives for rust prevention and wear resistance, but these valuable components lose effectiveness after about six months. My old car suffered because of this—I didn't change the oil on time for five years, and it ended up needing a major repair that cost over 8,000 yuan. Now I strictly follow the six-month oil change schedule. Although it hurts to spend a few hundred bucks each time, it's still much better than facing a costly engine overhaul.
Changing engine oil is primarily to protect the internal components of the engine. Parts like pistons and connecting rods rotate at high speeds, relying entirely on the lubrication provided by the oil. When I first started driving, I tried to save money by using the cheapest mineral oil for over a year, and the engine noise ended up sounding like a tractor. Later, a car-savvy friend reminded me that engine oil is like the blood in our bodies—its lubricating performance drops sharply over time, especially during cold starts in winter. Old oil loses its fluidity and takes several seconds to circulate through the engine, causing significant wear. Now I’ve learned my lesson: I change to full synthetic oil every 8,000 kilometers. After each change, the car runs noticeably smoother, and fuel efficiency improves by half a point. Regular oil changes also save money on engine cleaning.
