Can expired engine oil be used?

1 Answers
MacSkylar
07/29/25 10:23am
Expired engine oil cannot be used. The chemical composition of expired oil may have changed, which can affect the engine after being added. The functions of engine oil are: 1. To separate the surfaces of relatively sliding parts, thereby reducing wear; 2. To carry heat back to the oil tank and then dissipate it into the air, helping the radiator cool the engine; 3. To circulate carbon deposits, sludge, and worn metal particles from engine parts back to the oil tank, flushing away dirt generated on the working surfaces of parts through the flow of the lubricating oil. Signs that indicate the need for an oil change include: 1. Checking the oil viscosity—if there is no viscosity, the oil needs to be changed; 2. The oil color turns black; 3. Excessive black particles, metal shavings, or carbon deposits in the oil; 4. The oil has an unusual smell.
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