Oil Change: The Filter Needs Replacing

Most drivers have learned that every other time they have an oil change the mechanic asks if they would like to change the filter. Most of us, not knowing this component from a catalytic converter, pause ruefully and nod agreeing that yes it is time for that to be replaced. The truth is we don't really know what this part does. The lubricant seems too thick to go through a traditional filtration system so what exactly is the purpose of this part? Well, it is always possible to ask the mechanic and risk revealing our lack of knowledge and damaging the facade but instead we could just educate ourselves and save the embarrassment.

When a car is brought in for an oil change they do a number of different inspections to ensure that while they are replacing the lube there is not any other repair that needs to be done. Often they will offer to do things that are within most people's skill set like change the windshield wipers or replace the washer fluid. One thing they always offer is to replace the lubrication filter. This does need to be done and is best left to the professionals.

The lubricant that is used in engines plays multiple roles. It obviously reduces friction between moving parts and that is the major function. It also cools parts by performing heat exchange in the pan as it circulates. The final job it does is to remove dirt and grime and debris from the surface of the inner workings and take them out of the cycle. This is where the filter comes in. It strains out particulates and leaves the lube free of contaminants. The problem is that there are often a lot of contaminants in an engine and they tend to accumulate and reduce the ability of liquid to flow through the filter.

Fortunately, the manufacturers of these strainers are aware of this shortcoming and have built a safeguard into the design. When a certain level of pressure is reached a valve opens and allows the fluid to flow uninhibited. This is great in that it allows the engine to continue to function and be lubricated but not so good in that the bad pieces floating around are just getting spread back through the system.

One tip for oil change is not to go with the cheap filter. Nicer models have significantly more material in them providing better protection and longer life. With these nicer options it is possible to change it out every other oil change whereas the cheap ones need to go every oil change.