What is a fuel filter? How does it work?

Guest Blogger March 12, 2023 Auto Blog

The fuel filter is an indispensable component for petrol and diesel internal combustion engines. It filters out dirt, debris, metal fragments and other small impurities while ensuring that there is a sufficient flow of fuel to the engine. Modern fuel injection systems are particularly vulnerable to clogging and contamination, which is why the filtration system is so critical for maintaining engine performance. Contaminated petrol and diesel can cause havoc to car engines, resulting in sudden speed changes, a loss of power, sputtering and misfiring.

Diesel engines are sensitive to even the smallest contaminants. Most diesel fuel filters also feature a drain tap at the bottom of the housing which allows any water or condensation to be removed from the diesel. The filtration component can normally be found either inside the fuel tank or inside the fuel line. As fuel is pumped out of the tank, it passes through the filter and foreign particles are trapped. Some newer vehicles use a strainer that’s integrated with the fuel pump instead of a filter.

Signs that your fuel filter need to be replaced

The average lifespan of these filters used to only be around 30,000 to 60,000 miles. Nowadays the recommended replacement interval can be anywhere between 30,000 and 150,000 miles. It’s important to know the symptoms of a clogged or faulty fuel filter and replace it in good time to avoid engine failure.

Signs that it’s time for a replacement:

What to look for when choosing a fuel filter

It is advisable to look for trusted brands who ensure strict compliance with the standards and specifications of manufacturers as the components need to perform as efficiently as the original parts. Popular aftermarket brands like Ridex and VALEO offer full compliance at more affordable prices. Product descriptions normally include a list of compatible vehicle models and OEM numbers for reference. This should make it easier to determine which part is right for you.

Most car engines use a screen mesh or pleated paper filter element. Filtration screens are usually made from a polyester or metal wire mesh, while pleated inserts are typically made from polymer resin-treated cellulose or polyester felt. Pleated filters, such as the RIDEX 9F0023 fuel filter, are the most common, the main advantage being that they are able to trap even the finest particles and are cheap to produce. Mesh components, on the other hand, are often reusable and offer higher fuel flow rates, reducing the risk of fuel starvation. The quality of the rubber seals will also affect the component’s performance. The RIDEX 9F0023 is sold complete with accessories and gaskets.

Like air and oil filters, there are multiple types of fuel filter and different ways of installing them. The most common ones include in-line, in-tank, cartridge, canister and spin-on components. Spin-on filters became popular due to their convenience. The sturdy metal housing protects the internal components and they are easy to install without specialist tools. However, there are concerns over their environmental impact. Unlike cartridge components, none of the parts are reusable and a lot of steel is used in their production. Cartridge inserts like the 9F0023 use less plastic and metal, and are easier to recycle.

Filters are specifically designed for either petrol or diesel engines. Diesel parts are normally distinguished by their bowl-shaped housing, water draining valve and large seals. The example product used above is only suitable for diesel applications for car brands such as Fiat, Ford, Peugeot and Volvo. It has a seal diameter of 101 mm and a height of 75 mm.