How to Check Engine Oil Quality?
2 Answers
Methods to check engine oil quality mainly include: 1. Oil Drop Test. Place a drop of oil from the oil pan on a white paper. If the center black spot is large, dark brown, uniform without particles, and the surrounding yellow infiltration is small, it indicates the oil has deteriorated and should be replaced. If the center black spot is small and light in color with a larger yellow infiltration area, the oil can still be used. 2. Dipstick Identification. Pull out the oil dipstick and observe the scale lines against a bright light. If the scale lines are not visible through the oil on the dipstick, it means the oil is too dirty and needs immediate replacement. 3. Rub 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, the oil is still good and can be used. Otherwise, it should be replaced. 4. Pour Test. Take a small amount of oil from the oil pan and pour it into a container, then slowly pour it out. Observe the gloss and viscosity of the oil flow. If the oil flow remains thin, long, and uniform, it can still be used. Otherwise, it should be replaced.
To check engine oil quality, I'd like to share my routine method. As a seasoned car owner, I make it a habit to inspect the oil monthly: park on level ground, pull out the dipstick when the engine's cool, wipe it clean and examine the sample. If the color appears dark brown or black like coffee grounds, it indicates severe oxidation; drip a drop onto paper to observe the spread—clear and even is ideal, cloudy or with impurities means it's time for a change. The smell test works too: no unusual odor is normal, while a burnt smell suggests overheating or contamination. Check the viscosity: dip your finger in the oil and slowly pull apart—if it's too thin, it loses protective properties. This simple inspection saves considerable repair costs and extends engine life. Always cross-check with maintenance records: typically change oil every 5,000 kilometers, don't delay too long to avoid engine wear.
