Government agencies and car manufacturers have worked to reduce the emissions and harmful gases in our air over the last few decades. Automakers downsized car engines and pushed EVs, while the government placed restrictions on ICE vehicles and their exhaust systems to ensure that most of the harmful gases are trapped. Diesel vehicles, which bear the brunt of the blame for putting out the nasty stuff in the air, have several filters that reduce or contain emissions, including the diesel particulate filter (DPF).
The DPF traps and removes harmful soot particles instead of releasing them into the atmosphere. It removes those pollutants through a process called regeneration, in which the trapped soot is burned off. The DPF can regenerate using active or passive methods. The former relies on the ECU to raise the exhaust gas temperatures to burn the soot, while the latter can be accomplished with some spirited driving on the highway. However, the DPF can still get clogged, which will likely cause your diesel engine to become sluggish, and, in time, could result in DPF failure. Replacing a DPF can be expensive: anywhere between $1000 and $5000 or more.
So, how do we prevent a diesel vehicle's DPF from clogging? While some of the most effective options include adhering to safe driving practices and following a strict maintenance schedule, there are several things you should do. Here are a few tips.
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The DPF works effectively — and efficiently — at high temperatures and during long drives, as these conditions cause soot to be burned off from the filter. Slow speeds don't allow the engine to generate high temperatures, which are required for the DPF to work properly. Once enough soot accumulates in the DPF, it can cause the DPF warning light to appear on the instrument cluster. The longer this light remains present, the likelier it is that your DPF gets clogged, necessitating a visit your local garage to actively regenerate it.
You should avoid frequently driving a car equipped with a DPF on short trips or in slow-moving traffic, where exhaust temperatures may not allow for the DPF regeneration process to take place. It's recommended to drive at speeds of around 40 mph or higher to help the DPF regenerate properly — faster, in this case, is actually better for your car. Some also suggest incorporating highway driving into your regular schedule to help keep the DPF healthy.
On the other hand, frequent heavy acceleration and deceleration can increase soot production. That puts additional strain on the DPF, and if the filter cannot regenerate, the excess soot can build up and eventually cause clogging. The same applies to towing heavy loads, as the engine — and, in turn, the DPF — must work harder to manage the increased soot production. It's important to stay within the manufacturer's recommended towing capacity and take breaks during long trips to reduce strain on the engine and DPF. Smooth and fast is what you should be aiming for when driving a vehicle equipped with a DPF.
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EGR valve or injector issues in diesel vehicles can lead to increased oil and soot leaving the engine and entering the DPF, potentially causing it to become blocked. You should give your DPF-equipped vehicle the right oil, as regular diesel oils contain components that can clog the DPF, leading to a loss of power. Oil used in DPF vehicles must contain the correct SAPS (sulfated ash, phosphorus, and sulfur) rating, and for vehicles equipped with a DPF, low- or mid-SAPS oils are generally recommended.
Some owners of DPF vehicles swear by cleaning additives, which lower the soot's burn-off temperature from around 1,112 degrees Fahrenheit to 662 to 842 degrees Fahrenheit, thereby aiding the regeneration process. You should also keep an eye on the quality of diesel you use, as low-sulfur diesel produces less soot, which helps keep your DPF from clogging.
DPFs are built to last 100,000 miles or more, but they can fail much earlier if not properly maintained. Modern diesel engines are designed to minimize pollution, but the failure of a single emissions component can cause the entire system to function poorly — and it could even leave you stranded. Do not ignore warning lights that pop up on the instrument panel. If your vehicle's fuel consumption increases drastically or you observe an increase in smoke from your exhaust pipe, get the vehicle checked for any major issues. Your car will also automatically regenerate when it senses that the DPF is clogged, so ensure that you let the system run and complete the regeneration process when the lights blink on the instrument panel.
