Why Must Cars Have Their Engine Oil Changed?

[DamianFitz]

Cars need engine oil changes for the following reasons: 1. To improve and enhance lubrication for moving friction components in the engine. 2. To extend the engine's service life. 3. To optimize the engine's lubrication conditions and reduce friction between moving parts. Steps for changing engine oil: 1. Lift the vehicle, remove the underbody shield, and place a container with approximately 10-liter capacity beneath the drain plug. 2. Loosen the drain plug, use an air gun to blow into the oil filler opening for two minutes. After complete drainage, tighten the drain plug and wipe it with a tissue to check for leaks. 3. Reinstall the underbody shield, lower the vehicle, and use a funnel to add new oil through the filler opening.

[LeAngela]

Oh man, changing engine oil is something you really gotta take seriously. When I recently changed the oil on my old Focus myself, I noticed the used oil was as black as soy sauce with metal shavings in it. This stuff gets pounded by pistons inside the engine daily, gradually losing its lubricating ability under high temperature and pressure. Fresh oil is like new blood, forming a protective film between components, while used oil mixed with gasoline combustion byproducts can't maintain proper viscosity. Ever seen a neighbor's car with cylinder scoring? That's what happens when failed oil causes direct friction between piston rings and cylinder walls. Regular oil changes can save you from major repairs - my decade-old car still has crystal clear engine sounds to this day.

[McMia]

I remember last year when I was driving on National Highway 318, the sudden oil warning light on the dashboard really scared me. Later, at a car repair shop in Lhasa, I learned that overused engine oil oxidizes and deteriorates, and its detergent components lose effectiveness. When the tiny oil grooves in the piston rings get clogged with sludge, the power noticeably drops, and fuel consumption increases. The mechanic used an endoscope to show me the inside of the engine—the carbon deposits washed out by the new oil looked like black sesame paste. Now, I make sure to change the oil every 8,000 kilometers. After all, with hundreds of engine parts rotating thousands of times per minute, they all rely on that thin oil film for protection.

[Mia]

Engine oil plays a far more complex role than commonly assumed. Beyond lubricating metal surfaces to reduce wear, it performs four critical functions: sealing combustion chambers, cleaning carbon deposits, cooling pistons, and preventing corrosion. As usage time increases, the molecular chains of base oil break down, thinning the oil film, while additives gradually deplete. When total acid number exceeds limits, the oil can even generate acidic compounds that corrode copper sleeve bearings. Laboratory data shows regular oil changes reduce early engine failure rates by 72% - a far more cost-effective approach than post-failure repairs.

[ReaganDella]

Last week, my best friend noticed a metallic friction sound when cold-starting her Mini, which turned out to be caused by not changing the oil for six months. Aged engine oil becomes particularly viscous in winter's low temperatures, preventing the oil pump from supplying oil promptly. During those days, she kept complaining about a sudden 2-liter increase in fuel consumption—this was actually due to poor oil flow increasing engine operating resistance. Now she's learned her lesson and changes the oil every 10,000 km as per the maintenance manual, and the car runs much smoother. A reminder to watch for three signs of oil degradation: a pungent smell on the dipstick, darkened color, and abnormal viscosity.

[SanJason]

Every trucker knows engine oil is the lifeblood of an engine. When I drive light trucks for long distances, I pay special attention to the oil change interval. Under heavy load conditions, oil performance deteriorates particularly fast. Once I saw a fellow trucker trying to save money by using cheap mineral oil, and the sludge ended up clogging the oil passages, causing the camshaft to burn out. High-quality oil can withstand high-temperature shearing under harsh conditions and maintain sufficient oil pressure. Nowadays, I always choose fully synthetic oil with SN/SP certification, which provides reliable protection even after an extra 5,000 kilometers compared to regular oil. Actually, judging oil life is quite simple: in congested city driving, it degrades after 5,000 kilometers, while highway cruising can extend it up to 12,000 kilometers.