How to Guides

Engine Oil Filter

Zaki Moulvi posted this on Jun 16, 2014

For optimal engine performance, engine oil needs to be free of any debris or contaminants. The engine oil filter is designed to remove any particles inside of the engine oil before they cause damage to essential components.

Engine Oil Filter History

The first automotive engines did not employ any type of filter system for the engine oil.  As a result, frequent oil changes were necessary to keep the car from breaking down.  Those first cars that did use an oil filter simply installed a small screen at the oil pump intake.  The bypass filter was created in 1923 by American inventor Bobby Evans.  The Purolater was placed near the bottom of the engine and would filter small portions of engine oil at a time while the rest was circulating through the engine, lubricating it.  This seemingly simple invention would help preserve the life of billions of car engines in the future.

As car technology evolved, a valve was incorporated into the oil filtering system. This overpressure relief valve allows oil to bypass the filter if the flow rate is too slow.  This usually occurs when the filter becomes clogged or the oil has become too thick, either due to cold weather or a large amount of contaminants and sludge inside.  This relief valve is necessary to avoid a backup of oil at the filter from affecting its flow to the engine.

An anti-drainback valve was also incorporated into engines where the oil would drain from the filter once the vehicle was disengaged.  If there is no oil in the filter when the car is started, it will automatically travel there first, depriving the engine of the motor oil it needs.

Engine oil filters are made up of either cotton materials or pleated paper filter material.  These materials will trap any particles suspended in the engine oil and hold them as the oil flows freely through.  Over time, the filtering material will become clogged with these particles, necessitating its replacement to avoid engine damage.

Early filter versions were constructed so that only the element itself was replaceable, not its housing.  This made changing them messy and difficult.  By the 1960’s this method was replaced entirely with the spin-on oil filter design, which contained the filter and its housing on one unit.  Changing it became as simple as unscrewing it from its mount and replacing it with a new one.  The downside to the spin-on oil filter is that it generates a lot of waste, encouraging car makers in the 1990’s to revert back to the original element only replacement design.

Replacing the Oil Filter

Changing out the engine oil filter is a critical part of vehicle maintenance.  Your owner’s manual for your vehicle will give you guidelines on how often the filter should be changed.  Every time you change the oil in your car you should be changing the filter as well.  You can check on the filters performance by examining the engine oil that is circulating through it.  Using the oil dipstick, smear the engine oil on a white cloth.  Dark is not always bad, but if the oil seems gritty or sludge-like then the engine oil filter is no longer doing its job.

Engine oil filters are designed and built to be engine specific.  Check your owner’s manual and make sure that the new oil filter you purchase has the exact specs that your car needs.

You will most likely find the filter near the bottom of the engine.  Depending on the manufacturer it will be either blue, black, white or orange and its shape will be cylindrical.  To remove it you will need a special oil filter wrench that can be bought at any auto parts store.  Have a small empty container nearby to catch the oil that is remaining inside of the filter when you remove it.  Loosen it with the wrench and then by hand you should be able to twist if off the rest of the way.

It is important that you clean the gasket before installing your new filter and apply a small amount of engine oil to ensure a tight seal.  Turn it clockwise by hand until it is snug and then use the oil filter wrench to give it another 3/4 turn.  This will ensure that it is being held firmly in place.  Be careful not to over tighten the filter as this could cause it to crack or leak.

Your engine oil filter is a crucial element in keeping your engine from breaking down.  Engine oil is designed perfectly to lubricate all of the moving parts, and any particles that are allowed to build up in the oil can cause those parts to break.  By checking and replacing yours often, you are helping to extend the life of your cars engine.

Categories: Autowiki Car Systems