Engine oil plays many roles in allowing an engine to run properly over time. Here are the most important ones:

  • Lubrication

The main role of engine oil is to lubricate the engine parts, which are constantly in friction. It thus reduces friction which tends to increase part wear.

  • Cooling

The energy lost through combustion and the friction between mechanical parts causes the engine temperature to rise. Part lubrication provided by the engine oil helps to release the heat through the lubrication circuit. It supplements the coolant, which can only cool certain parts of the engine.

  • Cleaning

While less known, the cleaning power of engine oil is fundamental. Microscopic deposits build up in the engine and remain in suspension. They can consist of dust or combustion residue. Without engine oil, the residue would clog the engine and decrease its performance. The flow of engine oil continuously carries these impurities to the oil filter, where they are trapped.

  • Protection against corrosion

Fuel combustion generates corrosive acid that can damage metal parts in the engine. With the additives added to modern engine oils, corrosion is slowed down. Nonetheless, over time, and in contact with oxygen, engine oil may oxidise and no longer play its corrosion inhibiting role. That’s why engine oil must be changed regularly.

  • Sealing

Engine oil also enhances engine sealing, and more specifically the sealing of pistons and cylinders. A protective layer is deposited between the various parts, sealing any clearances that may arise.

Good to know

For engine oil to truly serve all its purposes, the level must be checked regularly in order to change the oil at the right time. Overused oil no longer plays its role, which is detrimental to the general condition of the engine and its parts.


For vehicle owners, engine oil firstly avoids costly repairs. Without a lubricant, the engine would quickly be seriously damaged. In strict terms, this is what a quality engine oil offers.

  • Ensures a longer engine lifespan

By reducing friction between parts and by cleaning the entire engine, engine oil prevents the engine from clogging and becoming damaged. Mechanical parts last longer and corode less. The engine therefore performs greater and its lifespan is increased.

  • Ensures proper running of the engine

An oiled engine runs better. Good lubrication is in fact essential to avoid serious mechanical damage. In addition to engine performance, the cost of maintenance is also affected.

  • Decreases fuel consumption and CO2 emissions

If a engine oil is overused, or if it’s level is too low, the resulting friction alters the engine’s energy efficiency, which in turn increases fuel consumption. A high-performance oil also reduces polluting discharges in the atmosphere.


Not all engine oils are the same. It is important to choose an oil that is suited to your vehicle and local climate conditions to enjoy all its benefits. There are three types of oil:

  • Mineral engine oils
  • Semi-synthetic engine oils
  • Synthetic engine oils

In addition to the type of oil, there are various parameters such as viscosity, which is expressed in two grades that are marked on the oil container (for example “5w30”): the grade when cold, and the grade when hot. These grades indicate oil fluidity according to temperature (high or low). Depending on engine design, the oil should be more or less fluid or more or less viscous. To choose the right oil, see your vehicle owner’s handbook or get advice from a professional.