Oil filter - as the name implies - is a filter designed to remove contaminants from engine oil, transmission oil, lubricating oil, or hydraulic oil.
Oil filters are used in many different types of machinery. Of our interest in particular is the use of the oil filter in internal-combustion engines in motor vehicles.
Other vehicle hydraulic systems, such as those in automatic transmissions and power steering, are often equipped with an Oil Filter of some type as well.
While in this article we will direct our discussion primarily to the Automotive Engine Oil Filter application, where the filtration of Motor Oil is utilized.
However, the same concepts apply no matter what the end use of the Oil Filter is or which fluid is being filtered .

Motor oil has a number of big jobs:

• lubricates internal parts

   

• helps cool the engine by transferring heat

   

• seals piston ring - cylinder bore interface

   

• absorbs contaminants

   

• suspends wear particles

   

• suspends soot that forms as a result of combustion.

   

Some contaminants go into suspension and some are chemically grabbed by the additives.
Additives constitute up to one-fourth of Motor Oil's makeup by volume.Acting by itself, oil would eventually become saturated with contaminants and allow the internal parts to wear. That is one reason why we have filters in all modern engines.

Engine Oil System

Oil is pumped from the oil sump by oil pump through the oil filter and then distributed by oil passages through out the engine to the bearing surfaces that need lubrication. Other less critical areas that do not need a pressurized oil are lubricated and cooled by oil splash - for example: valve stems and valve guides.

Oil Filter

The oil enters the oil filter under pressure through the holes on the perimeter of the base plate.The "dirty" oil then passes through the filter media where it is "cleaned".
It then flows through the central tube and back into the engine oil passages through the usually threaded hollow center mounting stud.