DPF in BMW – problems and repair of diesel particulate filter in cars with diesel engines

What is a DPF?

The abbreviation Diesel Particulate Filter has been adopted into the Polish language from the English language and stands for Diesel Particulate Filter, which is installed in cars with diesel engines in order to maintain the quality of exhaust emissions that comply with the stringent EURO standards. In a properly functioning engine, this filter ensures that emissions of dangerous soot and carbon particles are stopped. However, its service life is predetermined and does not cover the entire life of the car. For most BMW models equipped with DPF filters, the manufacturer’s assumed service life is about 200,000 kilometers. Gasoline cars use a catalytic converter, which we wrote about in a separate article.

N47 – Diesel engine (Diesel) in BMW

Use of diesel cars

If we buy a new car, we have peace of mind for a period of several years. Even when using the vehicle in urban cycles, we should not encounter problems related to its operation. The only exception is the phenomenon of the oil level in the engine, which we should pay close attention to.

As a result of the automatic afterburning of the DPF, the fuel injection phase is prolonged and the dose of fuel is gradually increased. If the process falls into driving for 20 to 30 minutes, everything is fine, our filter will not clog up too quickly. If we drive mainly in the city in sections of 10 to 15 kilometers, spending time in numerous traffic jams, the subsequent afterburning processes are not complete. The result is not only faster clogging of the filter, but also significant dilution of the engine oil by excess unburned fuel, which trickles down the cylinder walls into the oil sump. Hence the messages about exceeding the maximum engine oil level from automatic measuring systems.

To keep the engine from leaking, the oil must be dropped. For environmental reasons and the necessary precision, such an operation can only be performed at a car service center. In addition, you should perform more frequent inspections – every 15-20 thousand kilometers, rather than every 30 thousand kilometers (the suggested interval). We will then avoid surprises associated with sudden damage to an unlubricated engine or a seized turbocharger.

DPF Particulate Filter In BMW

Used BMW car with diesel engine and DPF filter

The average age of vehicles imported to Poland is 12 years. Taking into account the mileage of vehicles in the European Union in the region of 20,000 kilometers per year, it is easy to count that imported cars have more than 240,000 kilometers on the odometer. In the vast majority of these vehicles there is a problem with the functioning of the DPF. It is, of course, possible to check at the car service center, using diagnostic computers, the degree of clogging of the filter and its operating (firing) history.

The “Oil Service” message on BMW 3 Series and 5 Series (E36/E39) indicates the need for an auto service

What can we do if our BMW is already communicating that it has a problem with the DPF or is in emergency mode (displays check engine light, DPF light, no power)?

1. Cleaning the existing filter. If the degree of its clogging and exhaust pressures do not repeatedly exceed the allowable pressures, you can attempt chemical cleaning and firing while driving with a diagnostic computer. Correctly completed, the procedure allows the filter to continue to operate for a period similar to that of a new filter, that is, about 150. to 200 thousand kilometers of mileage. Such a repair can be performed in our service center.
2. Replacement of the DPF filter with a new one. New filters from BMW warehouses are offered, as well as numerous replacements also produced in Poland. The prices of original filters scare off potential customers and range from 7. thousand zlotys upwards, depending on the engine version and its age. Replacements from Polish factories are highly competitive in price, as they are available for as low as around 2. thousand zlotys. They provide an adequate technical level of performance and proper operation of the engine and accessories. In our offer we have available original filters and replacements at attractive prices.
3. DPF removal. Unfortunately, the operation, in addition to the low price, does not provide any benefits, and can cause many technical and formal problems. Our BMW without a filter will not allow normal operation. Depending on the engine version and age, it may react differently to sudden changes in combustion parameters transmitted by pressure sensors and probes to the engine controller. At best, a glowing check engine light will appear, and at worst the engine may go into emergency mode (limiting power and vehicle speed). The software change offered with DPF removal by many service centers does not solve the problem, but only disables some of the warnings displayed to the driver. Most significant, however, are the formal problems we may encounter in operating such a vehicle. Stricter technical inspections, which have been announced for a long time, will also cover exhaust gas quality and emissions, as well as compliance with the EURO standard. If the standard is exceeded, the owner will be banned from using the vehicle.

BMW X5 with diesel engine

Consequences of removing the DPF

The ongoing peak of the holiday travel season is a good time to draw attention to this phenomenon. Numerous inspections by uniformed services in Poland, as well as in Austria, Germany or the Benelux countries, have the ability to technically inspect exhaust gases directly on the road. In such a case, the finding of a significant excess of the EURO standard declared in the registration certificate ends not only with a high fine, but also with the immediate seizure of the vehicle and towing it to a police parking lot. From there it can only be taken away on a trailer after paying heavy fines and administrative costs. It is unthinkable to drive in such a country a “dug-out”, which we can often meet on our roads. Traffic police are sensitive not only to Polish license plates, but also to such phenomena. Then the whole holiday plan may lie in ruins.

Given the consequences described above, we strongly advise against removing the DPF from the vehicle. It is much better to solve the defect in a legal, safe and good for the environment way.