How does Engine Oil Work

The lubricant that most vehicles can’t function without.

Engine oil – or motor oil as it’s also known-is designed to lubricate the inner components of internal combustion engines, as well as to protect them against corrosion and keep them cool while in use.

It’s made from two main elements: base stock and additives. The base stock commonly ma Ices up approximately 95 per cent of the solution and is either made from petroleum, synthetic chemicals or a mixture of the two. The base stock is responsible for lubricating an engine’s moving parts and removing built-up heat.

The additives, meanwhile, account for roughly five per cent of the oil and it is these chemicals that are responsible for finely controlling oil viscosity and lubricity, as well as protecting the numerous engine parts against wear and tear. For example, zinc dialkyldithiophosphate (ZDDP) is a frequently used additive for preventing engine wear, while magnesium sulphonates help the oil to break down impurities and engine sludge.

Engine Oil grade and viscosityEngine oils are rated by both their grade and viscosity. Any oil can either be single-grade, with a set viscosity level, or multi-grade in which the oil can act at two different viscosities depending on its current temperature.

(Read also 5 Engine Oil Myths, Motor Oil Myths and Facts, 5 Facts About Changing your Oil)

The latter is most prevalent today, to cater for vehicles used all year round in various different weather conditions. The flow-rate of both single-and multi-grade oils is measured on a viscosity grade scale, which includes 11 grades ranging from 0 to 60. Lower-ranked oils are thicker than higher-ranked ones, making them more suitable to cold environments, and vice versa.