Is it okay to not change the engine oil for seven months in a car?
2 Answers
It is acceptable for a car to go without an oil change for seven months. Engine oil, also known as motor lubricant, is composed of base oil and additives. The base oil is the primary component of the lubricant, determining its fundamental properties, while additives compensate for and improve any deficiencies in the base oil's performance. Engine oil is categorized into full synthetic, semi-synthetic, and mineral oils. The functions of engine oil include: 1. Neutralizing acidic substances produced by combustion gases to prevent engine rust and corrosion; 2. Preventing pollutants and oxide impurities generated during combustion from adhering to the engine's interior, maintaining cleanliness; 3. Reducing friction and damage between moving parts; 4. Absorbing heat generated in the engine's combustion chamber and piston tops to cool the engine; 5. Filling the space between piston rings and cylinder liners to prevent combustion pressure leakage.
Last time I delayed changing the oil for eight months, and the engine noise became noticeably louder. When I took it for inspection, the technician said the oil had thinned out like water. Engine oil typically has a shelf life of six months to a year, but in actual use, it deteriorates due to high-temperature oxidation, gasoline dilution, and moisture absorption. Seven months is indeed pushing the limit. Especially in northern winters with longer warm-up times or frequent short trips, oil degradation accelerates even faster. My rule of thumb now is to change the oil whichever comes first—time or mileage. Full synthetic oil can stretch to a year at most, but conventional mineral oil should never exceed six months. If you're still delaying the change, I suggest checking the oil's viscosity with the dipstick immediately. If it lacks that slick, oily feel when rubbed between your fingers, it's definitely time for a change.
