Most diesel cars and trucks come with what is called a DPF—a Diesel Particulate Filter. What is it, and how long is it expected to last on your vehicle? If you don’t even know what it is, you probably don’t know how to maintain it. We break down the ins and outs of the DPF filter here: what it is, how to take care of it, and what to do if it’s not maintained or if it’s tampered with.
A Diesel Particulate Filter—What Is It?
A DPF is a specialized filter that captures and stores exhaust soot. They’re also known as “soot traps” and function to reduce the emissions generated by diesel vehicles. Like any device of this kind, DPFs have a limited capacity and the trapped soot needs to be emptied or burned off to restore the DPF’s functionality.
The DPF’s regeneration is supposed to burn off the excess soot and clean away what becomes deposited in the filter. This reduces harmful exhaust emissions and prevents the plumes of black smoke from blowing out the exhaust pipe of diesel vehicles when they accelerate.
Removing Or Modifying Diesel Particulate Filters
It’s illegal to remove the DPF filter, and it can invalidate both your car warranty and insurance policy. Also, selling your vehicle afterwards can become a troublesome experience.
If your DPF is blocked, clogged, or damaged, or there is a fault in the system, you should see the typical maintenance light appear on the dash of your vehicle. It’s a good idea to take your vehicle in to be serviced instead of attempting to clean or replace the DPF yourself.
There are a number of things that can create a blockage in your DPF, such as cruising at low speeds or making frequent starts and stops. It’s not a good idea to drive your diesel vehicle during short city-bound trips or to drive it through residential areas where you will make frequent stops. This can increase the chance of soot blockages in your filter. Poor servicing and maintenance can also worsen this factor. Any poorly serviced DPF will fail much faster than one that is well maintained—the average DPF should last upward of several hundred thousand miles. Esnure you are using a good dpf service when getting any work done.
How To Maintain Your DPF
There are a number of ways to maintain your Diesel Particulate Filter, such as using the right type of oil, following the manufacturer's maintenance schedule, and watching how you drive. Improper oil type, or using oil additives, may contain substances that damage and block filters because they are filled with impurities not designed for your engine type, or are not recommended by the truck manufacturer.
When your DPF is full of soot it should be able to properly regenerate itself, either through passive or active action. Passive regeneration happens at a consistent speed, such as traveling on a highway or freeway. This allows the exhaust temp to burn at a higher level for a longer period of time so that it can burn off any excess soot in the filter. It’s advised to drive your diesel vehicle for 30 to 50 minutes at a sustained speed on a highway or freeway to help clean the filter efficiently.
Since not all drivers can maintain this speed regularly, there is another type called active regeneration. This is when extra fuel is injected automatically—this helps the filter reach a stable temperature to burn off any stored soot. But again, there can be a problem if the travel distance is too short to maintain the temperature, and the regeneration process might not occur at all. There can also be additional issues if the filter is partially blocked, which may activate your vehicle’s warning light.
Signs That Your DPF Regeneration Is Working, And What To Do If It’s Not
There are a number of things to note if an active regen is taking place.
You should notice:
- A change in engine noise
- Increase in fuel consumption
- Increased idle speed
- Cooling fans cycling
- A hot exhaust smell
If your warning light stays on, and both active and passive regeneration fails, you should take your vehicle in for service. Serious damage can be caused to your DPF and to the vehicle itself if you ignore it, and the initially inexpensive issue can become very expensive. Some shops may enact a forced regeneration of your DPF to help it out, and this is typically the most successful way to remove excess soot and force the DPF to work again, and for them to test the aftertreatment system.
Anyone who owns a modern diesel vehicle should take care in maintaining their DPF, especially in the case of their driving habits, fuel, and oil. A blocked DPF can increase emissions and make your vehicle less suitable for driving.
You should get your truck regularly maintained, especially if it’s a high-mileage vehicle. If your DPF needs to be replaced, do it sooner rather than later—or it can be expensive, and potentially cause extended downtime, or extra towing expenses if it fails while traveling. Make sure you get a quality dpf filter replacement to maximize longevity.