Can expired engine oil still be used?
3 Answers
Expired engine oil cannot be used. Engine oil absorbs moisture, undergoes chemical and physical changes, which reduces its lubrication, cooling, sealing, and anti-corrosion properties. Additionally, deteriorated oil can produce impurities that clog oil passages. Deteriorated oil not only fails to provide anti-corrosion protection but also accelerates component oxidation due to the absorbed moisture. Methods for storing opened engine oil: 1. Seal immediately after opening. After maintenance at a 4S shop or repair shop, immediately tighten the oil bottle cap; 2. After sealing the oil bottle, store it in a dry and cool place, ensuring it is not exposed to sunlight to prevent oxidation of the oil inside; 3. When using stored oil for the next maintenance, do not pour all of it into the engine; retain a small portion.
Expired engine oil is truly unusable. I once found a bottle of expired oil in my garage and thought I could save some money by using it, but my mechanic friend gave me a stern lesson: he said the additives in the oil break down, drastically reducing lubrication effectiveness, increasing friction between engine components. At best, it accelerates wear and raises fuel consumption; at worst, it can cause cylinder scoring or bearing damage, leading to repairs costing thousands—totally not worth it. Now, I always check the production date on oil bottles during maintenance, store them sealed in a cool place, and replace them if they’ve been sitting for over six months. Regular maintenance may seem minor, but it prevents major issues—safe driving comes first. Remember to change it every 5,000 km or six months; don’t penny-pinch at the expense of bigger problems.
As someone who frequently ponders car maintenance, I've learned a hard lesson from using expired engine oil: trying to save money ended up costing me more. After expiration, the viscosity of engine oil changes significantly, its lubricating ability declines, and engine wear increases, potentially leading to major repairs costing tens of thousands in the long run. Economically speaking, a fresh oil change costs a few hundred yuan, but saving small amounts may trigger major malfunctions. I recommend checking the oil's condition by observing its color and viscosity—if abnormal, don't use it. Engine oil typically has a shelf life of 18-24 months, so discard it after use. Storing oil in a cool, dry place is crucial—don't harm your engine for convenience. Proper maintenance saves money and brings peace of mind.
