An oil filter is a filter designed to remove contaminants from the engine oil. Engine Oil is the lifeblood of your engine. Without the oil filter, harmful particles can get into your motor oil and damage the engine. Specks of dirt and metal shavings act like miniature sandblasters when they float suspended in engine oil. Their abrasive ways can especially wear down engine bearings, leading to low oil pressure. That, in turn, could lead to big-time engine damage.Over time, an oil filter gets so clogged with impurities that it no longer effectively cleans the oil. Almost all manufacturers recommend having your oil filter replaced every time you get an oil change, but check your ownerƒ??s manual for specific recommendations.