How to Tell When Car Engine Oil Needs to Be Changed?

[McEllie]

Here are the relevant methods to determine when car engine oil needs to be changed: 1. Smell Test: Pull out the dipstick and smell it. If there is a strong sour odor, it indicates the oil has deteriorated and should be changed. 2. Finger Rub Method: Rub the extracted old oil between your thumb and index finger repeatedly. Good quality oil will feel lubricated, with few particles and no friction. If you feel impurities, poor viscosity, or even a gritty sensation, it should be changed. 3. Color Identification Method: Take a clean white filter paper and drop a few drops of old oil on it. After the oil seeps in, good quality oil will leave no powder, feel dry and smooth to the touch, and show a clear yellow infiltration zone. If it appears dark brown with impurities, it should be changed. 4. Light Inspection Method: Pull out the dipstick and hold it at a 45-degree angle under light to observe the oil droplets. If you can clearly see no particles in the droplets, the oil is in good condition. If there are many particles, it should be changed.