What is the role of the fuel filter and when should you change it?

Your engine will last longer and perform better if it is burning the purest fuel possible. A key component in achieving this is the fuel filter – and learning how to replace it is highly important. It’s relatively straightforward in most situations.

The role of the fuel filter

You should know how to change your vehicle’s fuel filter and do so regularly, in accordance with your car’s service manual and owner’s guide. It sometimes surprises drivers to learn that the fuel in their car needs to be filtered or ‘cleaned’ before it can be safely or efficiently used by their engine. There are a number of potential reasons for this.

Fuel filter

Firstly, although the fuel delivered to a typical retailing petrol/gas station will have been produced to the highest standards in order to avoid contaminants, once it is placed into the tanker, it’s a different story. The inside of the tanker may contain small particles of rust or dirt and after delivery into the holding tanks at the garage, this problem is multiplied. Then, once you fuel your car, there is the potential problem of yet more rust, corrosion and dirt particles in your own petrol tank. All of these things could be harmful for your engine and it is the fuel filter that prevents them getting through.       

How the filter works

In many cases, your fuel filter will be a cartridge made of special paper or other materials that sits in a steel container somewhere within your engine compartment. The exact shape and design may vary considerably from one model to another but those on diesel vehicles are often like a small bowl or vase-shaped. Your owner’s manual should tell you where your fuel filter is and perhaps how to remove the cartridge. That cartridge should be replaced regularly and at least in line with the manufacturer’s recommendations.

Fuel filter replacement

The exact approach to how to change your vehicle’s fuel filter may change from one make to another but in most cases you will need to ensure that you have disconnected or ‘closed off’ the fuel supply to the filter as the first step. Replacing the fuel filter is typically straightforward and well within the scope of normal DIY vehicle maintenance.

Diesel considerations

It’s worth keeping in mind that diesel fuel filters also often serve a subsidiary purpose of storing water that has sunk to the bottom, leaving the less dense diesel on top for use in your engine. When you change your diesel fuel filter, you should also look for a drain valve that will allow you to drain off this accumulated water. This again is an easy job and the presence of a little water is not cause for alarm. What is important is to make sure that it does not get into the combustion system. Draining off is a routine task that is well within the capabilities of most vehicle owners. 

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