BMW Diesel Particulate Filters
Diesel Particulate Filters (DPFs) have been around for a while in BMW engines. Since 2009 every diesel engine requires one. They help reduce harmful emissions being released into the atmosphere.
Because the diesel engine combustion process produces harmful particles, the DPF stores and prevents them from entering the environment. Without a DPF, your BMW engine will no longer meet emissions regulations.
Failure to stay on top of DPF maintenance can result in expensive repair bills and render your vehicle unroadworthy.
This ultimate guide provides BMW owners with the information they need to reduce the problems caused by DPFs, explaining how they work and insights into the importance of regular DPF maintenance including cleaning.
If you have a diesel BMW or want to educate yourself more about how Diesel Particulate Filters work, then keep reading to find out more!
How do DPFs work in my BMW?
Diesel Particulate Filters’ main function is to capture and store particulate matter (aka soot) which is emitted from diesel engines during their combustion. Usually, diesel engines pollute the atmosphere and DPFs aim to reduce the amount of contaminants released into the air.
DPFs are usually made of ceramic materials with lots of small holes to trap soot. Over time, the DPF can get clogged with soot and often they need cleaning to allow proper exhaust flow. This process is commonly known as ‘regeneration’.
The main ways a DPF can get unclogged are:
Passive Regeneration: Sometimes, the engine’s heat is high enough to naturally clean away the soot from the exhaust gases. This typically happens on highways or busy roads when the engine is working hard, making the gases hot and cleaning the filter on its own.
Active Regeneration: If the engine isn’t hot enough for passive cleaning, it needs active cleaning. Here, the engine control unit (ECU) adds extra fuel to increase the exhaust gas temperature, burning away the soot in the filter. This process can last around 30 minutes and might trigger a warning light on your dashboard.
The regeneration process is vital to ensure your BMW diesel engine prevents harmful pollutants from being released into the atmosphere.
Why are DPFs Needed in BMW Diesel Engines?
DPFs are used to meet Euro 5 regulations. These regulations have been around for many years and DPFs reduce exhaust gas emissions by lowering the CO2 output of a BMW diesel engine.
A vehicle that does not meet emissions standards is illegal and without a DPF your exhaust gasses will be above the legal limit. Since 2014, vehicle MOT tests in the UK have required DPF checks, and they are unavoidable. Without a properly functioning or fitted DPF, you could be subject to a fine or driving penalty.
What Causes BMW Diesel Particle Filter Problems?
Diesel Particulate Filters (DPFs) can harm the engine in your BMW and make it perform poorly.
Here are common reasons for DPF issues:
- Getting Too Hot: When DPFs get too hot, they might melt or break, which makes them less effective or makes them stop working altogether.
- Getting Blocked: Soot particles can build up during regeneration and not burn off properly, leading to blocked DPFs. This blockage can lower engine performance and restrict exhaust flow.
- Not Performing Maintenance: Skipping regular cleaning can clog the DPF, making it less effective.
- Dirty Fuel: If fuel has sulphur or water in it, it can harm the ceramic filters in DPFs, making them work poorly or stop working.
- Broken Sensors: Sensors that don’t work right can make the engine operate outside the DPF’s best range. This can lead to clogs or damage to the filter.
To stop DPF problems, stick to the maintenance schedule recommended by BMW, use the right fuel, and avoid idling too much. Checking the engine’s performance often and fixing any problems immediately can also prevent DPF trouble.
What Are the Signs of a Faulty DPF?
If your DPF isn’t working properly, you might notice:
- Odd Sounds: A blocked DPF can make strange noises like rattling and banging when exhaust pressure increases.
- Less Power: If your DPF is clogged or failing, your engine might not perform as well, leading to slower acceleration and less power.
- Strong Smells: A broken DPF can build up with unburned soot and dirt, causing a powerful smell in the exhaust.
- Warning Light: If your DPF isn’t working, a warning light usually pops up on the dashboard. It often looks like a down arrow or says “DPF”.
- More Fuel Use: When the DPF is faulty, the engine may consume more fuel, which means it’s not as efficient as it could be.
You should consult professionals when experiencing any issues with your DPF. Our team at SB Autocare are BMW experts and can quickly diagnose and fix DPF issues. After all, ignoring these signs might only make the problem worse and lead to more expensive repair bills.
Tips for Keeping Your Diesel Particulate Filter (DPF) Healthy
Here are some suggestions from our DPF experts to keep your BMW running smoothly:
- Keep Your Vehicle Maintained: Regular maintenance like oil changes and air filter replacements can help prevent engine issues that might harm your DPF.
- Minimise Idling: Try to avoid leaving your engine running when not in motion or driving short distances, as this can lead to DPF blockages.
- Choose the Right Oil: Opt for low-ash or ashless oils to reduce soot build-up in your DPF. These oils produce fewer particles when burned, helping to keep your filter clean.
- Use Quality Fuel: Using high-quality fuel is crucial for DPF health. Poor-quality or contaminated fuel can damage the filter and impact engine performance negatively.
DPFs for BMWs in Summary
Modern BMW diesel engines are equipped with Diesel Particulate Filters which need to be working at all times. Without them, emissions standards are not met, and you could fail your MOT test or face a hefty fine. Poorly performing DPFs can lead to engine issues and reduce the performance of your BMW.
To ensure that your BMW diesel engine is working optimally it’s important that you regularly maintain it, use good quality fuel and oil, and drive at motorway speeds to activate passive regeneration to clear the DPF.
As soon as you notice any trouble with your DPF, it’s advised to address it as soon as possible. Otherwise, you could damage your engine which may cost a lot in repairs.
For expert diagnosis, maintenance, and repairs for your BMW, reach out to our team of experts at SB Autocare today. Call or visit us to book your appointment.
