What is the purpose of an oil filter?

The primary purpose of an oil filter is to remove unwanted contaminants from the oil. This can include dirt, metal particles, soot, and other debris that accumulate over time and can cause damage to the engine. The oil filter ensures that the oil circulating in the engine is clean, which is vital for maintaining engine performance and longevity. By filtering out these impurities, the oil filter helps to prevent wear and tear on engine components, maintain proper lubrication, and promote efficient operation. Without a functioning oil filter, engine oil could become contaminated, leading to decreased efficiency and potential engine failure.

The other options do not accurately describe the oil filter's purpose. For instance, while recycling oil is a beneficial practice, an oil filter does not primarily serve that function; its main role is filtration. Likewise, altering the viscosity of the oil—whether thickening or thinning it—is not a function of the oil filter. The filter's design focuses solely on cleaning and purifying the oil rather than changing its physical properties.