What are the reasons for engine oil deterioration?
2 Answers
Engine oil deterioration occurs due to the following reasons: 1. Air filter damage. The function of the air filter is to filter impurities from the air entering the engine, thereby purifying the air. Generally, a standard car has only one air filter, while luxury cars may have two. The air filter is located inside the air filter box in the engine compartment. To access the air filter, the air filter box must be opened, and it is secured either with clips or screws, both methods ensuring the box is sealed properly. 2. Oil dilution and emulsification due to water. Water can enter the cylinder block or crankcase due to a damaged cylinder head gasket or other reasons. When the water content exceeds 0.1%, the antioxidants and dispersants added to the oil become ineffective, accelerating the oxidation process of the oil. When the oil contains a significant amount of water, its lubricating properties deteriorate, viscosity decreases, and the oil film's anti-friction effect weakens. In mild cases, this leads to premature oil deterioration and rusting of components, while severe cases can cause engine seizure or bearing failure, leading to serious mechanical accidents.
There are quite a few reasons for engine oil deterioration. After years of driving, I've found the main issues stem from prolonged use and environmental factors. For instance, when I frequently drive long distances, the high engine temperature causes the oil to oxidize and thicken, reducing its lubricating effectiveness. Also, dust or moisture seeping into the oil from outside makes it dirty and accelerates aging. Forgetting the oil change interval is the worst—last time I delayed my oil change by two months, the oil turned black, and the engine started making strange noises. Now, I regularly check the dipstick and replace the oil immediately if I notice it's dark or the viscosity has changed, to avoid costly engine repairs. Additionally, frequent cold starts during short trips can dilute the oil with fuel, causing damage. I recommend developing a habit of changing the oil every 5,000 kilometers or every six months to keep your beloved car running longer.