Engine oil is a lubricant used in internal combustion engines to reduce friction between moving parts. It helps to keep the engine running smoothly by minimizing wear and tear, which can lead to damage over time. Engine oil also helps to cool the engine by carrying heat away from the moving components. In addition to lubrication, engine oil plays a crucial role in cleaning the engine. It picks up dirt, debris, and contaminants, preventing them from causing harm. Regularly changing the engine oil is essential for maintaining engine performance and longevity, ensuring that vehicles operate efficiently.