Many modern diesel vehicles (especially the European varieties) from new to the 5 years old mark, now days are often fitted with an exhaust filter known as a DPF. The DPF traps exhaust soot, then burns it off in a controlled way. The trapping of soot is good for the environment, however continuous ‘stop-start’ city driving, as many diesel owners now know, can cause a blockage. Without longer trips and some highway driving, a modern diesel doesn’t reach a high enough operating temperature for the prescribed DPF burning off cycle to take place. This burn off or regeneration process happens automatically, without any real disruption to how the car drives, so the only real sign something is up, is when a warning light appears on the dash.
If you fall into the the category of regular, short (10-15min) trips in traffic, with no highway driving, the chances of overloading your DPF with soot are high. Common signs are warning lights and poor, sluggish performance. If a DPF light appears, first things first, go for a 30min plus highway drive to try stimulate a DPF regeneration. If the warning light doesn’t turn off take the car to the dealer or a workshop for a proper diagnosis.
Prevention For the stop start drivers out there, the best solution is to take regular highway drives and to get in the habit of using Liqui-Moly DPF Anti-Clog p/n 2729 every third tank of fuel.
Cleaning the DPF If the DPF becomes blocked it can be cleaned, this is a new process that often avoids the high cost of replacement. It has to be performed by your local workshop and should take about 2-3 hours dependent on the car and the severity of the problem. For more information on the DPF system in your vehicle, check the owners manual, ask your local mechanical workshop or call Liqui-Moly Technical on 1800 350 622.