The oil filter helps remove contaminants from your car engine's oil that can accumulate over time as the oil keeps your engine clean. Clean motor oil is important because if the oil were left unfiltered for a period of time, it could become saturated with tiny, hard particles that can wear surfaces in your engine. It is very important to choose a high quality oil filter because the internal construction and quality of the filter has a huge effect on the life of your car's engine.