Engine oil plays a very important role in the engine. It helps to cool the engine by transferring heat. Sealing the gap between the piston ring and the cylinder wall; absorbing contaminants; and suspending soot particles as combustion residues. Contaminants can be organics such as fungi and bacteria in the air. Inorganic particles can be a lot of things, including dust that is drawn into the engine during operation.

The outside of the oil filter is a metal can with a gasket that can be fastened to the mating surface of the engine. A gasket is attached to the base of the can and a hole is formed around the area inside the gasket. The center hole is threaded to mate with the oil filter assembly on the engine block. The inside of the jar is a filter material, the most common being synthetic fibers. The engine's oil pump moves the oil directly to the filter and then enters the oil filter from the hole in the perimeter of the base plate.

Dirty oil passes through the filter media and then returns through the center hole where it re-enters the engine. Typically, filters have two media types: primary and secondary. The primary medium can block particles as small as 25-30 microns (human hair size is 65-70 microns) and the secondary medium can block particles as small as 5-10 microns. More filter cross reference you can get from www.filters-king.com.