Why does my car need an oil filter?
As you probably know the oil system is a critical part of your car’s engine. When the engine is off oil gathers in the oil pan. Once the ignition is turned the oil pump starts to circulate the oil from the pan around the car’s engine. Before it is pumped into the engine itself the oil is passed through a filter. The filter is there to remove any traces of dirt or metal that may have contaminated the oil.
If these particles of dirt and metal enter the engine they can act like abrasives. This means that as the oil is held under pressure by the moving parts of the engine, tiny particles can cause damage to metal surfaces. It is like washing a car with a sponge that has grit or sand in it. Once you press it down against the car’s paintwork and move it around the surface can very easily become scratched or damaged. Inside the engine this can lead to damage and reduced oil pressure surprisingly quickly.
However, the filter is extra important because the oil is designed to catch these tiny particles and hold them in suspension preventing them from damaging the engine until the oil is recirculated again and filtered. It is worth changing your filter every time you change your oil.
Once the oil has been filtered it passes through the oil pressure sensor. This makes sure there is sufficient pressure in the oil for it to resist the forces in the engine and to make sure all of the engine surfaces that need lubricating and protecting get covered. Should the filter become clogged the oil pressure will fall and the oil pressure gauge on the dashboard will illuminate. If the filter is blocked completely a pressure release valve will open and allow the oil to flow around the engine again. This will prevent the engine from becoming damaged due to lack of lubrication but is only a very short-term fix as the engine will become damaged by the unfiltered oil and the particles it contains. However, it is more damaging if there is no oil present due to a blockage.
