DPF filter clogged - how to deal with it?

When the diesel particulate filter does not want to burn out while driving, the car loses power, and the filter failure indicator is constantly on on the dashboard, different thoughts come to the head of the drivers. One idea is to remove the filter and get rid of the problem once and for all. However, in order to avoid legal trouble, it is better to choose one of the legal solutions. And it doesn't have to be very expensive. 

The process of spontaneous removal of soot from the DPF filter while driving is one of the integral elements of the engine control ECU. When the system detects that the filter is full of soot, it attempts to burn it under the right conditions. One of the factors necessary for the implementation of this process is correct engine temperature. The other is the specific speed level, and the other is the load on the drive. Under suitable conditions, as a rule, a larger amount of fuel is supplied than usual, which does not burn in the cylinder, but ignites in the filter. That is why we are talking literally about soot burning.

If one of the required parameters changes so much that it deviates from the required minimum, the process is interrupted. Burning soot can take up to several minutes, therefore, in urban conditions, and even on a regular domestic highway, sometimes it is impossible to carry it out. Ideally, you should be driving at a constant speed on a freeway. Fortunately, in recent vehicles, the soot burning process requires less and less restrictive conditions and can be carried out even in a parking lot or while driving at a variable speed. The key factor here is only the temperature of the engine, which should not be too low. If the cooling system is working, everything will be fine.

What happens when soot cannot be burned?

There comes a time when the DPF filter, for various reasons, becomes so clogged with soot that the process of burning it during normal operation does not work. Then on the dashboard a warning about the so-called. filter failure. The engine may lose power and even go into emergency mode. To make matters worse, repeated attempts to burn off the soot can result in large amounts of diesel in the engine's lubricating oil, which is dangerous for the engine. Thinned oil does not provide the same protection as regular oil. That is why, especially in vehicles with a diesel engine and a particulate filter, it is so important to check the oil level regularly.

What can be done about a clogged DPF filter?

There are several methods to deal with a clogged DPF filter. Here they are, in order of magnitude of the problem:

• Stationary shooting - if during the movement the process of carbon burnout does not go smoothly, and everything is in order in the engine and exhaust system, then for some reason the driving conditions are not suitable. Soot burning can be started in service mode. Depending on the type of vehicle, this can be done while parked in the workshop by connecting to a service computer, or while driving by running the appropriate program in the vehicle. Then the car must be driven in a certain way and only for this purpose. The cost of such a service is usually PLN 300-400.
• Cleaning the filter with chemicals – there are preparations for chemical cleaning of the DPF filter on the market. With a jack and basic tools on hand, this can be done in a matter of hours. It is enough to apply the drug to the filter in the place of the pressure sensor in front of the filter, and then start the engine. There are also drugs that are added to the fuel. They support the soot burning process, but it all depends on the driving style and the conditions that must be met at this time. Usually such chemistry costs several tens of zlotys.
• Professional filter cleaning – seminars on so-called filter regeneration DPF offers cleaning services. The term "regeneration" is a bit misleading as the filters are never regenerated. The fact is that the precious metals placed in the filter burn out over time and are not replaced. On the other hand, on special machines even the dirtiest filter can be cleaned, resulting in restoration of its operability, or at least an appropriate exhaust gas flow. Since the car does not analyze the composition of the exhaust gases, but only measures the pressure in the filter, the filter thus cleaned for the control computer is as good as new. The cost is about 300-500 PLN, but you need to take into account the need for dismantling and assembly. If you do not do it yourself, then in the workshop it can cost about 200-300 zł.
• replacing the particulate filter – although various articles threaten the DPF with a price of several thousand zlotys, it is worth knowing that there is also a replacement market. And it's very well developed. Depending on the shape and size, you can buy a DPF filter for a passenger car for PLN 700-1500. This is not a high price for a part, which can cost 2-4 times more in ASO. And this is not a high price for restoring the diesel engine's performance legally, without cheating, both at the service station at the PTO, and when reselling the car. Removing the diesel particulate filter is against the law, and selling a car with a cut filter without informing the buyer is a simple scam.