Below are the 5 most important functions of engine oil
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.
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.
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.
4. 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.
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.