How to Determine When to Change Car Engine Oil

[VanKira]

There are several methods to determine whether the engine oil needs to be changed: 1. Smell Test: Pull out the oil dipstick and smell it. If there is a strong sour odor, it indicates the oil has deteriorated and should be changed. 2. Hand Rubbing Method: Rub the extracted old oil repeatedly between your thumb and forefinger. Good-quality oil will feel smooth, produce few grindings, and cause no friction. If you feel impurities, poor viscosity, or even a rough texture, it should be changed. 3. Color Identification Method: Take a clean white filter paper and drop a few dots of old oil on it. After the oil seeps through, 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 oil dipstick and hold it at a 45-degree angle under light to observe the oil droplets. If you can clearly see no grinding particles in the droplets, the oil is still good. If there are many grinding particles, it should be changed.