The concept of a diesel particulate filter has been a fundamental part of diesel vehicle design for a very long time, with some of the first designs dating as far back as the 1970s.
However, whilst Citroen did offer DPFs as early as 2000 in order to prepare for Euro 5 regulations before even Euro 3 had completely come into force, it was not until the late 2000s when diesel cars and filtration became a hot topic for car owners.
A big reason for this was the surge in popularity of diesel cars after the Great Recession began, which made petrol cars unaffordable to maintain for many people struggling against the current.
Diesel cars were cheaper to run due to being more fuel efficient, and as Euro 5 came into force around the same time, DPFs were all but compulsory to have fitted, and it is essential to make sure they are regularly cleaned and maintained to keep them working at their best.
However, an ounce of prevention is worth a pound of cure, and with that in mind, here are the most common reasons why DPFs get blocked or otherwise fail.
Too Many Short, Slow Journeys
Diesel particulate filters do have a self-cleaning system that allows them to get rid of unwanted particles, but not every journey will make this system work.
Generally, the car needs to be driving at high speeds for enough time for the engine to warm up to its ideal temperature. This helps it to easily and cleanly burn away the excess soot, ensuring that it is working effectively.
Roughly half an hour of motorway or dual carriageway driving on a regular basis will be enough to ensure it regenerates by itself, but if this is not possible, there is an automatic active regeneration system that works as long as a car is driving over 40 mph for at least ten minutes.
Empty Adblue Tank
Most modern diesel cars do not use only fuel to activate the DPF system but also use an exhaust fluid known as AdBlue which helps lower pollutants and clear the filter.
AdBlue is an essential fluid for a diesel car, but when it runs low, not only does it affect the car’s performance but also can make the DPF more likely to clog up and get damaged.
Low Fuel Tank
The active DPF cleaning system requires a healthy fuel level to work, and if your car happens to be running low on fuel, one of the first systems that is shut down to preserve it is the DPF cleaning system.
Exactly how much this affects the DPF and at what fuel level can vary by car, but try to avoid ending up in low-fuel situations if possible.
Wrong Oil
Not every engine oil is suitable for every engine, and some engine oils can contain additive ingredients that can undermine the DPF filter and even potentially block it.
Make sure you choose an engine oil that is DPF compatible; most compatible brands will either have “DPF” or “DPF compatible” on the packaging, and any mechanic or expert with diesel cars can make a recommendation.