Oil A quart of oil is composed of about 60 percent oil and 40 percent additives. We suggest changing engine oil four times a year. How the product is produced and what can make one oil different than another.
Motor oil is composed of two basic ingredients, base oil and additives.
Most the additives perform the important function of protecting the base oil from deterioration and decomposition caused by the harsh environment inside the engine. Also important is keeping those contaminants not filtered, in suspension until the oil is drained. Base oils are refined from crude oil. Contaminants such as sulfur, nitrogen and unsaturated hydrocarbons must be removed during the refining process. How well these are removed make a big difference in the quality of the finished product.