How to Test if Engine Oil Needs to Be Changed?
2 Answers
Testing whether engine oil needs to be changed can be done using the following methods: 1. Observe with an oil test paper: Take a small amount of oil from the dipstick and drip it onto the oil test paper, then let it sit overnight, waiting for the oil to fully spread on the paper. If the edges between the oil ring, sediment ring, and diffusion ring are harder, the more the oil performance has degraded. 2. Judge based on driving feel after an oil change: Engine oil performance has a 'shelf life.' If at some point you feel the power is 'sluggish' and acceleration is slower, this indicates the oil has reached its 'shelf life' and needs to be changed. 3. Smell test: Pull out the dipstick and bring it close to your nose to smell. If there is a strong sour odor, it means the oil has deteriorated and should be changed. 4. Hand rubbing method: Rub the extracted old oil between your thumb and forefinger repeatedly. Good quality oil will feel lubricated, produce little residue, and have no friction. If you feel impurities, poor viscosity, or even a gritty sensation, it should be changed. 5. Color identification method: Take a clean white filter paper and drip a few drops of old oil onto it. After the oil seeps in, good quality oil will have no powder, feel dry and smooth to the touch, and have a clear yellow infiltration zone. If it appears dark brown with impurities, it should be changed. 6. 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 residue in the droplets, the oil is in good condition. If there is a lot of residue, it should be changed.
Testing whether engine oil should be changed, I often use simple DIY methods. First, ensure the car is parked on level ground with the engine turned off and cooled for at least 15 minutes to allow oil to settle. Pull out the dipstick, wipe it clean, reinsert it, and pull it out again to check: the oil level should normally be between the high and low marks; oil color is the most intuitive indicator—fresh oil is bright yellow or light amber, but once it turns dark brown or completely black, it’s time for a change. Then, dip your finger in the oil, spread it, and feel its viscosity; if it feels thin like water with no stickiness and poor lubrication, it needs immediate replacement. I prefer using an oil test strip for more accuracy—drip a drop of oil on the paper, wait five minutes, and observe: a small spread means it’s still good, while excessive spreading or black residue indicates severe contamination and aging. I check every 5,000 kilometers or three months, especially after long trips. Delaying oil changes accelerates engine wear, so act promptly if it appears dirty or degraded. The key to testing lies in visual and tactile assessment—it’s not hard to do.
