Symptoms of Engine Oil Deterioration?
3 Answers
After engine oil deteriorates, the specific manifestations are that as the usage time of the oil increases, the engine noise will become louder, and the engine will feel rough. Below are the related details: 1. Rubbing Test: Take a small amount of oil from the oil pan and rub it between your fingers. If it feels sticky and shows a stringy phenomenon, it can still be used temporarily without immediate replacement, as the oil has not yet deteriorated. 2. Clarity Check: You can also pull out the oil dipstick and observe the clarity of the scale marks under bright light. If the scale marks are unclear, the oil should be changed immediately because it is too dirty. 3. Oil Drop Test: Another method is to drop a small amount of oil from the oil pan onto white paper. If the central black spot of the oil drop is large, dark brown in color, uniform without particles, and the surrounding yellow infiltration is small, this indicates that the oil has deteriorated and needs to be replaced. If the central black spot is small and light in color with a larger surrounding yellow infiltration mark, the oil can still be used temporarily.
Symptoms of oil degradation are quite common, and my car sometimes experiences them too. Symptoms include increased engine noise, especially during acceleration or idling, sounding like a rattle; fuel consumption also rises significantly, previously 7 liters per 100 kilometers, now over 8 liters; the power feels sluggish, with less response when pressing the accelerator; the oil itself may turn black and thick, and checking the dipstick shows it's no longer bright golden but dark and sticky. The main reason is usually oil oxidation under high temperatures, leading to accumulated impurities and lubrication failure. If not changed in time, engine wear increases, and repairs can be costly. I recommend everyone develop a habit of checking the oil condition every few months and changing to synthetic oil at the recommended mileage for better durability, to avoid problems on the road.
I remember last year my car's fuel consumption suddenly increased by 15%, and the engine noise became annoyingly loud. When checking the engine oil, I found it had turned black and sticky, thick like ink, completely different from its clear appearance when freshly changed. This caused my car to lose power during acceleration and often shake during startup, making the entire powertrain feel sluggish. Ultimately, it was due to aged engine oil - accumulated contaminants reduced its lubricating performance, and prolonged use would increase engine burden. Since then, I've paid special attention to regular maintenance, always checking the dipstick before long trips. After timely oil changes, the situation improved significantly - the car runs much smoother now and saves on fuel costs.
