No oil change for one and a half years, mileage not reached, any impact?
2 Answers
Even the best engine oil will deteriorate after one year of use. Full synthetic oil should be changed even if the mileage limit hasn't been reached. The impacts are as follows: Possible insufficient oil volume: The engine continuously consumes oil during operation, though at a relatively slow rate. As long as there's no oil burning, oil shortage typically won't occur within the normal oil change interval. However, in certain situations like vehicle deceleration, bumpy road conditions, or body tilting, the oil pump may not be able to draw oil properly. Accelerated oil aging: Engine oil not only provides lubrication but also cooling. Although the heat absorbed by the oil is ultimately dissipated through the engine and coolant, insufficient oil volume reduces circulation cooling efficiency, potentially leading to higher oil temperatures and faster oil degradation. Increased engine sludge: Prolonged oil change intervals cause oil volume to decrease while the engine continues running, continuously generating particles. These particles keep dissolving in the oil until it becomes increasingly viscous. Potential oil filter failure: The oil filter is designed to clean the oil. After leaving the oil pump, all oil passes through the filter before reaching lubrication points. After lubrication, the oil returns to the oil pan and gets recirculated by the pump, passing through the filter again each time.
I've been driving for almost ten years and have seen this issue countless times. The shelf life of engine oil is much shorter than you might think. Even if you haven't driven the recommended mileage, exceeding a year and a half is pushing it. Engine oil absorbs moisture, oxidizes, and breaks down, reducing its lubricating properties by half. The most obvious sign is metallic friction noises during cold starts. My neighbor waited two years without changing it and ended up spending over 8,000 yuan on engine repairs. My advice: check the dipstick. If the oil is black like soy sauce and feels gritty between your fingers, change it immediately! Don't just rely on the odometer—the maintenance manual specifies a dual standard of 'six months or 10,000 kilometers.' Pay special attention to oil emulsification issues in vehicles used for short trips.
