If you drive a diesel vehicle, you may have heard of the diesel particulate filter (DPF), but you may not know what it does. In fact, you may never understand what this vital part is until you try to determine if your vehicle has a faulty diesel particulate filter (DPF). But how do you know if your DPF is clogged or bad?
When the DPF filter is blocked or clogged, the engine will weaken and a check engine light will often appear on your dashboard. It can also lead to increased fuel consumption and create a difficult starting situation. Additionally, you may also notice strange odors or problems with the turbocharger.
In this guide, we evaluate the symptoms of a clogged DPF filter. We’ll also show you why it’s important and discuss the cost of replacing it.
Bad or Clogged Diesel Particulate Filter (DPF) Symptoms
1. Check engine light
The first common sign of a bad DPF is a check engine light on your dashboard. The diesel particulate filter uses sensors to measure pressure and temperature before and after the DPF filter. If the pressure is not correct, the engine control module will turn on the check engine light on your dashboard.
If you see a check engine light on your dashboard, you should scan the trouble code memory with a code scanner to determine what is wrong.
2. Decreased engine performance
When the DPF is blocked, the exhaust system is significantly affected. The ability to effectively remove exhaust from the engine is hindered, causing system backup.
On backup, the engine starts to feel weak and slow. The more exhaust gases build up, the slower new fuel can be pumped in, leaving you without the ability to accelerate normally. In addition, the engine will have to use more power to evacuate excess gases.
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3. Poor energy efficiency
If the engine is not running efficiently, it will burn more fuel than normal. Part of the inefficiency comes from the blocked filter itself, causing more fuel to be pumped to perform the same task. This is also due to the need for more fuel to get the desired results from your engine.
With these problems, you will spend more money on the pump. As the price of diesel continues to rise, you will definitely notice the difference.
4. Boot problem
A blocked DPF creates a buildup of exhaust gases in the engine. This trapped gas can’t go anywhere, creating more pressure than normal. During this time, it becomes difficult to start the engine. In fact, the engine will not want to start unless this pressure is released.
This issue is more of a security design issue. If the engine were to start with all that pressure inside, permanent damage could occur, resulting in large repair bills. To save this money, it is best to clean the DPF before a blockage occurs.
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As exhaust gases build up in the engine, they can create a noticeable odor. Not only is it annoying, but it can also be dangerous.
Exhaust gases are not safe to breathe and may be flammable, putting you at risk of fire. Additionally, while these odors occur, it is difficult to know if something else is wrong.
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6. Damage to the turbocharger
With a blockage in the exhaust system, you must also consider the health of the turbocharger. When gas flow is impeded or slowed, temperatures can rise rapidly. When the problem is not resolved quickly, the turbine casing also becomes hot.
If nothing is done, the turbocharger will be damaged. If the casing is damaged, leaks may occur, and efficiency will decrease. This problem can also cause the oil to carbonize inside the turbocharger, which becomes dangerous for the engine itself.
Diesel Particulate Filter Location
The diesel particulate filter (DPF) is part of your diesel vehicle’s exhaust system. You can find the filter in front of the NOx trap, also known as the NOx storage catalytic converter. You will often find the DPF filter near the exhaust manifold.
It is also in front of the exhaust pipe, but will be behind the first temperature sensor. To remove the filter, you will need a screwdriver to remove the grilles and surrounding plates. After removing the plates, there may also be O-rings or other clamps to remove.
Diesel particulate filter function
The diesel particulate filter is part of the exhaust system. It is intended to trap particles such as ash and soot. The DPF is constructed with a ceramic substrate. Forms an effective honeycomb structure to trap debris.
The diesel particulate filter is designed to capture and store soot from the exhaust, so the diesel vehicle can have reduced emissions. This soot is periodically burned off to help regenerate the DPF. With this regeneration process, excess soot is burned off and deposited in the filter, reducing the harmful emissions and black smoke you are used to seeing in diesel models during acceleration.
DPFs have now been mandatory on all vehicles since 2007, according to EPA guidelines. These filters trap the material so the vehicle can meet strict emissions standards.
Diesel Particulate Filter Replacement Cost
A new diesel particulate filter can cost between $1,000 and $7,000. These new parts are never cheap, so it is important to keep the system running smoothly. Instead of replacing it, most people choose to clean it to make it last longer.
Considering that the DPF normally does not fail on a low-mileage vehicle, it makes more sense to clean it. After all, the cost of a new DPF could be more than the value of the vehicle itself. When properly maintained, the DPF should not need cleaning more than every 100,000 miles.
How to clean a diesel particulate filter
If you take the DPF to a professional to have it cleaned, you may hear it using the thermal method. This cleaning technique is also known as “baking and blowing.”
The DPF is put in an oven. With the increase in heat, the soot oxidizes, while the airflow pushes the ash out of the filter.
This other professional method has proven effective. A surfactant surrounds the ash particles, allowing water to more easily remove debris from the substrate.
Once the support has been cleaned, it must be dried completely. A special cabinet is required, so you will have to wait at least two hours before you can install it again.
3. Household cleaning products
If you don’t want to take your vehicle to a professional to clean it, you can try doing it yourself with a special additive. You can find some of the best brands for under $25 a bottle. These products are intended to break down soot and ash.
Follow all the instructions on the back of the bottle. You will need to place it in the fuel tank with the engine running. Once added, it is best to drive for thirty minutes. This helps the additive circulate through the system. No matter how fast you travel, it will work. Also, the DPF light may disappear if it was on before.
Although cleaning additives can break down some clogs, it is best to use them for maintenance. If you use a cleaner every three to six months, you shouldn’t have any clogging problems in the future.
If you still have problems after using an additive, you may need one of the professional cleaning methods. Visit your local diesel mechanic for more help.