What is the primary function of engine oil in a truck?

The primary function of engine oil in a truck is to lubricate engine components. This lubrication is crucial for reducing friction between the moving parts within the engine, such as the pistons, crankshaft, and camshaft. Proper lubrication minimizes wear and tear on these parts, extending their lifespan and ensuring smoother operation.

In addition to lubrication, engine oil also serves several other important functions, such as assisting in heat transfer, which helps maintain optimal engine temperature. It can also help seal spaces between engine parts, preventing loss of power through escaping gases. While engine oil contributes to other factors, such as cleaning and possibly improving efficiency, its fundamental role is to lubricate and protect engine components from damage caused by friction and heat.