Fuel filter: Why should you not forget to change it?

Oil and fuel filter
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A fuel filter is located in the fuel line system of almost every internal combustion engine. This filter removes dirt and small particles of rust from the fuel. Besides that, it also removes water, which causes corrosion of the injection system.

In this article, we will shed light on the function of the fuel filter, when to replace it, and why it is important not to forget to do so.


What is the function of the fuel filter?

Today's modern fuel systems have a very low tolerance for dirt and would not properly function without a fuel filter. Unfiltered fuel can contain large amounts of impurities that could enter the injection system and fuel pump.

If dirt enters the injection system or fuel pump, these components' rapid wear or malfunction could occur.

In addition, the fuel filter positively affects engine performance because the less dirt and water there is in the fuel, the more efficiently the fuel-air mixture can be ignited.

How does a fuel filter work?

Some fuel filters, found mainly in diesel engines, have a similar bowl shape that catches and collects water at the bottom. The water at the bottom of the filter can then be pumped out with the drain screw at the bottom.

Many fuel filters can be equipped with a water sensor, which signals excessive water in the fuel with a warning light on the dashboard. Water is an undesirable liquid in the fuel system, as it causes corrosion and insufficient lubrication.

A diesel heater may also be located near the fuel filter, which prevents the formation of paraffin wax in case of low temperatures, which could stop fuel flow to the engine.

If the fuel filter is not working properly and too much dirt gets into the fuel, the EPC warning light on the dashboard may also come on. This light also comes on in the event of many other problems, but one of the reasons may be impurities in the fuel.

The following are used to clean the fuel:

  • Filter inserts - They are placed, most often in a plastic package, and when they are replaced, only the insert itself changes, while the package remains unchanged. Filter inserts can be made of filter paper or textiles.

  • Replaceable fuel filter - The replaceable filter's cover and insert form a single unit. This unit is replaced with a new one during maintenance.

Replacing the fuel filter

The fuel filter must be changed regularly by replacing the entire filter or just its insert. However, some special filters are designed so that they can be cleaned and reused. If the fuel filter is not changed regularly, it can become clogged with dirt, which will cause a decrease in engine performance because not enough fuel is getting into the combustion chamber.

The price of fuel filters depends on the engine type and brand, while the price difference can be up to several tens of dollars. For example, with a 1.9 D 51kW diesel engine, only the filter insert itself is changed, which costs about $10, and with a 1.6 HDi 80kW engine, the entire filter is changed, the price of which is around $25.

However, we can say that the fuel filter is among the cheap parts our cars are equipped with, so there is no reason why you should not replace it if necessary.

How often to change the fuel filter?

The fuel filter replacement interval varies depending on the type of engine, the filter manufacturer, and the fuel quality you fill your car with. You should pay extra attention to this part, especially before the arrival of the winter season.