Engine oil is the moving force of an engine. The oil is located in the oil pan, which is further kept under your car which is attached to the bottom of your engine. All the internal and moving parts of your engine have to be properly lubricated by the engine oil. In case of improper lubrication, the parts will tend to wear out easily and will also lead to the failure of your engine. Using an oil filter will keep your oil clean and free from the debris. If you do not replace the filter from time to time, it is likely to get clogged and will never be able to pass the oil into your engine.