There are a great many additives, which can be divided into four main groups:
- Quality additives give the oil anti-wear, anti-oxidation and detergent properties. They also protect the mechanisms and the oil itself from ageing.
- Viscosity additives affect the viscosity-temperature properties of the oil. The additive used to make all-season motor oil keeps the oil from turning into jelly in the cold and from thinning to the consistency of water in hot weather.
- Pour-point depressant additives increase the oil’s resistance to solidifying. This component is used in winter and all-season oils. Unlike viscosity additives, they do not increase the oil’s resistance to thinning at high temperatures.
- Anti-foam additives: the name speaks for itself. Because the oil in an engine works under high pressure and lubricates mechanisms that turn at several thousand revolutions per minute, it must never form foam.
