Dirty diesel filter: The most common problem

Yes, you read that right. The vast majority of the time, when the emissions control system warning light comes on, it's due to excessive carbon buildup on the system's internal walls, not an actual malfunction.

Choking... But weren't we talking about dirt?

In the case of diesel filters, it's the same thing. Excessive carbon buildup clogs the internal walls and, in the long run, prevents them from functioning correctly.

As you can see below, the DPF, or FAP (as it's also called), is basically a huge strainer connected to the exhaust pipe outlet. Its function is to trap the pollution generated by the engine in the form of carbon particles.

These carbon particles are temporarily stored on its walls and then expelled as a gas during the regeneration process. All of this, in theory, helps reduce the level of polluting gas emissions into the atmosphere. And it makes the air in our cities a little more breathable.

Okay, if it's just a dirty sieve, why all the fuss?

At first glance, a clogged DPF might seem trivial. After all, it's not a part that directly affects the combustion system, or any other important system in the car... However, we must clarify that a DPF completely clogged to levels exceeding 70% forces the engine to work harder to expel the exhaust gases. This makes it work twice as hard, choke, and ultimately lose power.

In other words, a clogged DPF is like putting a plug in the exhaust pipe, thus limiting our engine. In such cases, when the automatic DPF cleaning process fails and the warning light for the anti-pollution system malfunctions comes on.

The warning light has illuminated, is it time to replace the DPF?

Not necessarily. While replacing the DPF with a new one was the norm years ago, it's now possible to completely clean it using specialized machinery. So, if you've taken your car to the garage and they've told you that you need a new DPF because the current one is too clogged, you should know that cleaning it is now a viable and economical option.

At Ecumotorstock, we are proud to be one of the first Spanish workshops to offer a complete DPF cleaning service. If you'd like to learn more about this service, you can click here for more information.

Wait... weren't DPFs supposed to be deactivated?

Yes, DPF removal has been, and still is, a common practice among those affected by partial or total blockage of the DPF. However, besides being illegal, we must warn you that this will be detectable in vehicle inspections (MOT/ITV). Diagnostic equipment is expected to be used in these tests starting this year.

My DPF isn't clogged yet, what can I do to prevent it from becoming blocked?

The biggest problem with the DPF system occurs during city driving, where frequent stops and starts are unavoidable. These stops interrupt the automatic cleaning process, as this process requires the engine to be running. In addition to not interrupting the automatic cleaning process, below we list other useful tips for preventing DPF blockage:

Don't fill the fuel tank completely.

Avoid fuel additives.

Always use the oil recommended by the manufacturer and check its performance every 1,000 kilometers.