What is the primary purpose of an oil filter in an engine?

The primary purpose of an oil filter in an engine is to remove impurities from the oil. Over time, engine oil can accumulate contaminants such as dirt, metal particles, and other residues that can hinder its performance. The oil filter plays a crucial role in ensuring that these impurities are captured and prevented from circulating through the engine. By filtering out harmful particles, the oil filter helps maintain the oil's cleanliness and effectiveness, which is essential for proper lubrication and overall engine health. Clean oil contributes to reducing friction, preventing wear and tear on engine parts, and ultimately extending the engine's lifespan.

The other functions like heating, increasing pressure, or cooling the oil do not align with the primary role of the oil filter in maintaining oil quality.