DPF: can the particle filter be cleaned / regenerated?

Thomas Wachsmuth 4 November 2020 Car repair & tuning guide, Tips, products, information & Co.

Reading time 9 Min.

Recently updated on January 27, 2022 at 10:49 am

A new diesel particulate filter is an expensive proposition. A change of the diesel particulate filter (Particle filters, soot filters, soot particle filters, diesel particle filters, DPF or remanufactured DPF - there are so many names) is usually necessary when this full is. This is usually done by lighting up a yellow lamp in the form of a filter or at the latest with the Engine control lamp (MKL) displayed in the cockpit. Strictly speaking, it shouldn't even come to this because the manufacturers state that the filters of the vehicles regenerate themselves and therefore do not need to be serviced. Actually is that also true: Have you driven a few hundred kilometers (the distances can vary depending on the manufacturer and the specific model), a filter regeneration is initiated by the engine management that goes unnoticed by the driver. With such a regeneration it happens that the soot deposits are burned by the high temperatures of the exhaust gases and the DPF is thus freed from the deposits. More about the specifics Process can be found in our article "How often does the particle filter burn free? Can I do this manually too?".

Particle filter cleaning: overview

Who is only interested in very specific areas around the topic Cleaning the particle filter interested, you can use the following jump labels to navigate directly to the desired topic with just one click. And just as quickly you can return to this overview from the selected menu item with just one click. However, we recommend our readers to always read the entire article. Some menu items are only really comprehensible and understandable once the full info article has been read.

Short journeys damage the DPF

However, if you only use your vehicle for short journeys, the heat required for combustion cannot be built up, or at least only very briefly, which ultimately means that the regeneration cannot be carried out correctly and the filter is always full. In this case it is then necessary that you move the vehicle over a longer distance so that the filter can be driven free - provided the filter is only filled with soot. With a so-called regeneration drive on country roads and highways, the "burn free" is guaranteed. But if the filter is full and actually needs to be replaced, then that is very annoying. Unfortunately, this is a very expensive thing that can cost up to 3000 euros, depending on the vehicle. If you're looking to save money here, maybe the Cleaning the filter is a welcome alternative for you. (Back to overview)

DPF full after approx. 120 - 200 tkm

The problematic thing is that during the process a little ash is always produced during the combustion, which, in contrast to simple soot, damages the filter many times more. This is because ashes cannot simply be burned and the filter cannot be opened in this case either. This very ash then unfortunately settles in the closed filter system in the channels and gradually clogs them. A rule of thumb says that there are around 1000 grams of ash for every 6 liters of diesel fuel. The resulting ash clogs the honeycombs and the driver is advised to continue driving in order to drive the filter free. However, the filter will eventually reach its limit in terms of its capacity. This is the case after approximately 120.000 to 200.000 kilometers - with room for maneuver upwards and downwards. (Back to overview)

Consequences with a full DPF?

A clogged filter can result in increased exhaust back pressure, which can result in higher fuel consumption and a drop in performance. In the worst case it can lead to one Turbocharger defect or even serious engine damage. As a rule, the engine's electronics prevent it by switching to an emergency program. If this is the case, you are practically forced to visit a workshop. There may still be the option to manually burn the filter free using the diagnostic tool. As a rule, however, this only provides a delay of a few kilometers or it is not possible at all. The manufacturer recommends that the filter should be replaced because it is too dirty. But as mentioned earlier, this is an expensive proposition. (Back to overview)

Cleaning instead of replacement - save money

The good news is that you do not necessarily have to have your diesel particulate filter replaced, as the filter can usually also be cleaned easily - and according to various providers up to 98 percent. The costs are definitely a reason to think about such a cleaning: cleaning and shipping usually cost no more than 300 - 500 Euro, plus any costs incurred for installing and removing or teaching the filter. Such cleaning normally takes 1 to 3 days. (Back to overview)

What methods are used for cleaning?

The procedures that vendors use to clean the filter vary.

Some companies weigh the filter exactly, then subject it to a pre-treatment and then clean it. Once this process has been completed, all that's left is a fine, light-colored dust, which, unlike ash, can be removed without any problems. To check the success of the cleaning, the filter is weighed again at the end of the treatment to determine the difference. But there is another possibility.

The filter can also use a special mechanical-thermal processwith which it can be cleaned without opening the filter housing. Here, however, the opinions differ somewhat. Some believe that the only way to properly clean the filter is to open the case. Allegedly this is the only way to get rid of the ashes in the channels. Other providers contradict this!

And also compressed air can be applied. The compressed air is used to clean the filters. For this purpose, a drinkable aerosol is added to the system for a short time. It reacts with the surface of the filter and removes the remaining dirt particles. This type of DPF cleaning is particularly quick and can only take a few minutes. At this point, we cannot give a tip as to which method is the best. The best way to do this is to use the experience study in various car forums. (Back to overview)

Manufacturers recommend refraining from cleaning

According to surveys, vehicle manufacturers tend to have a negative attitude towards cleaning the filter and advise against it. Furthermore, there is a risk that damage caused by cleaning can void the guarantee. However, if the filter is full, a vehicle warranty has usually already expired. And we are convinced that the background is actually more in the area of the market economy. If you can sell a new DPF filter, the manufacturers earn money from it, as opposed to cleaning it. (Back to overview)

Cleaning is a very effective method

Basically, filter cleaning is a plausible method of saving costs, provided it is carried out properly. And if a new component does not have to be produced, this not only saves money, but also the environment. (Back to overview)

How to carry out the regeneration drive?

A diesel car with a soot particle filter is usually properly "burned free" when driving for a few kilometers on country roads or the motorway. The soot filter must be brought to an elevated temperature from time to time. The so-called regeneration drive can help. And you don't have to lawn for that either. You should just make sure to move the car a few kilometers more in the medium speed range. The required temperatures of 500 to 600 degrees in the exhaust system can then be easily reached. (Back to overview)

Cleaning / regenerating a full particle filter yourself?

That is also possible. A suitable special vehicle tool, standard tool and a cleaning agent for soot particle filters are required. However, only experienced screwdrivers should clean the soot particle filter themselves. The sequence:

Let the exhaust system cool down in order to avoid tension cracks when pouring in the agent
Remove soot particle filter. Also remove all sensors.
Insert the cleaning agent hose into the opening of the particle filter

Fill in detergent. Shake the can well. Spray the agent into the filter every 5-10 seconds for 5 seconds (may vary depending on the provider). Rotate the probe while spraying so that the detergent arrives everywhere. Repeat the process until the can is empty.
Screw in the sensors again
Reset learning values. So that the probes know that the soot filter is now empty

Reset the learning values with the diagnosis device (regeneration may start manually)
Regeneration and test drive. To begin with, leave the car outside with the engine running for 15 minutes. Then drive for about half an hour at increased speed / engine speed on the motorway. (Back to overview)

Advantages and disadvantages of detergents

(Back to overview)

Disadvantages

No long-term forecast

Soot goes, ash stays

Chemicals can filters
damage

Benefits

DIY process possible

done quickly

Cheaper than everyone else #
Process

OEM replacement parts as an alternative?

With this method, the vehicle is only unavailable for the short period of time it is removed and installed. The old filter is removed and a refurbished and refurbished original soot filter is reinstalled. Of course, you have to make sure that the remanufactured diesel particulate filter can be installed in the vehicle without the operating license expiring. The provider must ensure that the flow behavior of the cleaned filter corresponds to that of a new diesel particulate filter. One possibility is a proof that work is carried out according to DIN EN ISO 9001, DIN EN ISO 1400 certificate. Thus, a cleaning process is used that reproduces the flow behavior of used filters with a quality comparable to that of new filters. (Back to overview)

Tutorials for cleaning the DPF

(Back to overview)

Summary information Diesel particulate filter full / clogged - options & costs:

Diesel particle filter is also referred to as DPF or diesel soot particle filter
the filter is regularly regenerated by the control unit
Ash in the filter ensures that at some point it is full and clogged (Depending on the vehicle and filter, this can be the case after 120.000 to 150.000 kilometers)

Symptoms / signs of a full / clogged diesel particulate filter
- Active engine control lamp / notice in the instrument cluster (warning lamp)
- Fault memory entry (info -> diesel particulate filter full)
- reduced engine power
- higher fuel consumption
- The engine cuts out while driving
- "Jerking" occurs when driving on a level track
- heavy smoke from the exhaust pipe
on Short haul the regeneration can often not take place correctly and the particle filter clogs faster
possible solution:
- additives put in the tank (they lower the temperature required for regeneration)

full of diesel particulate filters
- often with vehicles on short journeys
- Error readout using a diagnostic tester
- initiate manual regeneration (by means of a diagnostic tester via the engine speed when the vehicle is stationary or by means of a regeneration drive over approx. 30 minutes and more than 40 km / h)
if manual regeneration is not successful, the filter must expanded, cleaned manually or replaced with a new filter
The effort for the removal and installation varies depending on the vehicle model (approx. 2 to 4 hours plus teaching in the electronics)

Cleaning process
- Remove
- send to a specialist company
- The filter is burned free there (only possible if the filter is not damaged in any other way)
- Installation in the vehicle
Cost of changing the diesel particulate filter
- Total costs vary depending on the vehicle model
- is a new filter installed or the old filter cleaned?
- new part costs between 600 and 3.000 euros
- Cleaning of the diesel particulate filter is usually included under 500 Euro (plus labor for removal and installation)
- Workload depending on the vehicle between 2 and 4 hours (at an hourly rate of 100 euros, labor costs of 200 to 400 euros can be expected)
Attention: you should always replace the differential pressure sensor (it monitors the condition of the soot particle filter, material costs approx. 30 to 150 euros)

How the diesel particulate filter works
- Difference between Particle filter and Full flow particle filter
- Particle filters are mostly used for the Retrofitting a diesel particulate filter used (However, there is no link with the engine control unit here)
- Full flow particle filters are installed ex works (Retrofitting is not possible)
- Differential pressure sensor permanently monitors the condition of the filter
(Back to overview)

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