How Long Can Opened Engine Oil Be Stored?
2 Answers
How long opened engine oil can be stored varies depending on its type: 1. Mineral oil can be stored for 6 months; 2. Semi-synthetic oil can be stored for 9 months; 3. Fully synthetic oil can be stored for 12 months or even longer. Regardless of the type, this duration is sufficient to last until the next car maintenance. Engine oil, also known as engine lubricant, serves functions such as lubrication and wear reduction, auxiliary cooling, sealing and leak prevention, rust and corrosion protection, as well as shock absorption. Engine oil consists of two components: base oil and additives. The base oil is the main constituent of lubricating oil, determining its fundamental properties, while additives compensate for and improve the shortcomings of the base oil's performance, imparting certain new characteristics, making them an essential part of lubricating oil.
Speaking of the shelf life of opened engine oil, I've actually encountered this situation. Generally, fully synthetic oil can last about a year if well sealed, but there are a few details to pay attention to: the cap must be tightened properly, and it's best to wrap plastic wrap around the bottle opening to prevent air leakage. Don't store it in the trunk—high temperatures can accelerate oil oxidation. I always keep mine in a cool corner at home. Last month, I just used some oil that had been opened six months ago. It looked quite clear when poured out, but the mechanic said the performance degrades after being opened for more than half a year. It's advisable to mark the opening date on the bottle, and if you smell a sour odor or see cloudiness or separation, it's best not to use it.
