How to Determine When Engine Oil Should Be Changed?
3 Answers
Determining the oil change cycle involves the following points: 1. Based on engine running time and operating conditions Running time: Once oil is added to the engine, if the engine remains inactive, it is equivalent to being exposed to the air after opening, leading to deterioration. 2. Reaching the specified replacement date Deteriorated oil loses its properties and can no longer meet normal lubrication requirements. 3. Type of oil Semi-synthetic oil should be changed every 7,500 kilometers, while fully synthetic oil should be changed every 10,000-15,000 kilometers. 4. Replacement based on vehicle mileage Follow the car manufacturer's requirements (user manual) and change the oil when or before the specified mileage is reached. Below are methods to check if the oil has deteriorated: 1. Smell test Open the front compartment cover, pull out the dipstick, and smell it close to your nose. If there is a strong sour odor, the oil has deteriorated and needs to be changed promptly. 2. Finger rub test Take a small amount of oil and rub it repeatedly between your thumb and index finger. If you feel impurities, poor viscosity, or even a gritty sensation, the oil is in a deteriorated state and should be replaced immediately.
With over 20 years of car repair experience, I've got three practical tricks to check if engine oil needs changing. First trick is observing the oil color on the dipstick: fresh oil is translucent amber, turning tea-colored after 3,000 km. If it's black like soy sauce with metal flakes, your engine is suffering. Second trick is the finger test - dip some cold oil between fingertips in the morning. Ideal oil feels slippery with slight viscosity; if gritty or watery thin, it's overdue for replacement. Third trick is listening to engine sounds, especially during cold starts. Healthy oil produces crisp purring, while aged oil causes dry rattling noises. Veteran drivers know - waiting until the oil light comes on is too late. Change it at the first sign of trouble to avoid major repairs.
Last time during maintenance, the mechanic taught me a few inspection tips. After parking the car on level ground and turning off the engine for ten minutes, pull out the dipstick, wipe it clean, reinsert it all the way, and then remove it again to observe the oil mark: the oil level should be between the minimum and maximum marks. If it's below the minimum mark, add oil first and then observe again. Next, check the oil quality by dripping some oil onto a tissue and spreading it out. Good oil will form neat three-layer oil rings, while deteriorated oil will appear entirely black and not spread. Pay attention to the water temperature gauge during daily driving. If it frequently runs high, it could be due to aging oil that doesn't dissipate heat well. I test the oil with an oil test paper every 5,000 kilometers, and this small habit once helped me avoid a major repair. Don't blindly believe the long-lasting claims of fully synthetic oil; the key is to consider the actual driving conditions.
