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​How to Keep Your Diesel Particulate Filter Clog Free and Clean

Jan 7th 2022

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If your diesel engine or vehicle was made after 2009, you’ll need to clean what’s known as the diesel particulate filter (DPF). It filters the soot out of the exhaust gas to improve air quality, but the DPF will clog over time as you continue running the engine. This increases the chances of respiratory and cardiovascular illness as soot builds up in the filter. Learn how to stop the DPF from clogging up to keep the air as clean as possible.

What Does the Diesel Particulate Filter Do?

Diesel vehicles are known to create a lot of soot, a particulate matter that spreads easily through the air. When the soot comes out of the exhaust, it poses a direct threat to your health. It can enter the body via inhalation, ingestion or the eyes and skin. Exposure can lead to a variety of health conditions, including asthma, bronchitis, coronary heart disease, and even cancer.

The diesel particulate filter is designed to reduce the amount of soot in the air, but only if the filter stays clean. It’s made of cordierite, silicon carbide or a ceramic monolith that removes the soot from the exhaust before it gets released into the air. It should collect around at least 80 percent of all particulate material to be effective, but it depends on how much soot is already in the filter. If the DPF is working properly, it will collect up to 99 percent of all particulate matter to keep your fuel system clean.

The diesel particulate filter is a key component of the vehicle’s emissions reduction system. All diesel engines use some type of aftertreatment technique to limit the amount of nitrogen oxide coming out of the exhaust. NOx is considered extremely toxic for humans and the environment. Many engines use what’s known as exhaust gas recirculation (EGR) to prevent these pollutants from escaping into the atmosphere. Instead of letting the exhaust out the tailpipe, it gets recycled back into the combustion chamber. But the exhaust needs to be cooled to prevent the engine from overheating.

The EGR cooler is a complicated piece of equipment and is known to cause problems on certain types of diesel engines. The DPF and EGR cooler are directly related to one another. If your exhaust gas recirculation system isn’t working properly, the filter will clog more easily. Find replacement EGR coolers online to keep the exhaust gas the right temperature.

Many diesel trucks also use selective catalytic reduction (SCR) in place of or in addition to EGR. This method involves injecting diesel exhaust fluid into the combustion chamber, which triggers a chemical reaction that turns NOx into gases that form naturally in the atmosphere. Both of these methods are designed to reduce the amount of hot gases passing through the diesel particulate filter. Remember to maintain these after-treatment systems to keep your exhaust system clean.

Diesel Particulate Filter Exhaust System

Passive and Active Regeneration

The DPF is cleaned regularly via a process known as regeneration. The engine increases the temperature of the exhaust gas to burn off the excess soot that’s been collecting in the filter. This turns the soot into ash, which can’t be removed unless you manually remove the filter.

Regeneration can happen in one of two ways:

Passive regeneration occurs when you are driving as you normally would. The exhaust gas will need to burn hot enough to burn the soot, but most vehicles won’t get there on their own.

Active regeneration is when the vehicle purposefully adds fuel to the exhaust gas mixture to increase the temperature of the exhaust gas, thus burning away the excess soot. This usually occurs every 300 miles. The process usually takes between five and 10 minutes. However, you could interrupt the process if you aren’t taking the vehicle that far. Other types of engines require a special regeneration additive that allows the soot to be burned at lower temperatures.

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How to Manually Clean the DPF

Regular regeneration will help keep the DPF from clogging up, but the ash will still need to be removed. You should either clean or replace the DPF every 75,000 to 100,000 miles. It’s not recommended that you clean the DPF yourself. Most homes and drivers don’t have the necessary equipment to safely remove the ash, so it’s best to leave it to the professionals. Most companies and drivers send their DPFs to experts who specialize in the service.

There are two ways to manually clean a DPF.


This approach requires a large industrial oven, not the kind that you keep in your home. The filter is placed on a rack in the oven. The filter is then baked at extreme temperatures, which oxidizes the soot. The oven also uses compressed air to blow away the ash.


Others will use a special surfactant, which reduces the surface tension of the liquid, to make the ash easier to dissolve. They will then wash the ash out of the substrate of the filter. It is then dried in a special cabinet before being reinstalled.

How Does the Diesel Particulate Filter Get Dirty?

The DPF will naturally get dirty over time, but some habits can cause it to fail sooner than expected. Short, slow trips tend to be the biggest headache. That’s because the engine needs to reach a certain number of rotations per minute (RPM) to complete the regeneration process. This explains why diesel engines tend to be rare in the city. Be sure to take your vehicle out on the highway every once in a while to give it an automatic cleaning.

Poor quality oil can also contribute to the problem. Some oils have additives that can cause the DPF to clog more easily. Proper servicing and regular oil changes will help you preserve your filter for as long as possible.

You will notice a few problems behind the wheel when your DPF gets clogged. The check engine light should come on, so you can fix the issue before it gets any worse. When the filter is dirty, the exhaust won’t be able to flow through the engine as easily. This leads to a loss of power, poor fuel efficiency, delayed throttle response times, and excessive exhaust fumes.

If you notice similar issues and the filter is clean, your injection pressure regulator valve may also be part of the problem. It controls the pressure of the oil moving through the injectors in the Powerstroke engine. Find new IPR valves online to solve the issue.

The problem will also start to spread to other areas of the engine, including the EGR cooler and turbocharger, which sends a boost to the engine by forcing more compressed air into the combustion chamber.

If your filter is dirty, simply removing it isn’t an option. Your engine needs to comply with the latest diesel exhaust emissions standards, which means using a clean, reliable DPF. Some filters may be beyond repair if the material has eroded. Shop for diesel parts online to find a replacement.