What causes engine oil to become contaminated?

Engine oil becomes contaminated primarily due to the presence of combustion byproducts, dirt, and moisture. During the combustion process, residues such as unburned fuel, soot, and acids are generated, which mix with the engine oil. Additionally, dirt can enter through various openings or due to wear and tear on engine components, further contaminating the oil. Moisture can accumulate from several sources, including condensation, which occurs especially in colder temperatures or when an engine is not fully warmed up.

This combination of impurities can significantly degrade the oil's lubricating properties and overall effectiveness, leading to increased engine wear and potential damage. Regular oil changes and maintenance help mitigate this issue by ensuring that the oil remains clean and effective in lubricating engine parts.