Motor oils typically have a shelf life of four to five years. There are several factors that can affect the life of oil, such as exposure to extreme heat temperature changes and moisture. It's better to store oil in its sealed container instead of opening it.
Some common signs of a bad oil are color change, haziness, solid material and settling out of the additives. If the oil has a milky appearance, it has been contaminated with water. A common problem of keeping oil in a shelf is that engine standard requirements change over time; a motor oil that met the requirements years ago might not be suitable any more.