INSTANT EXPERT
On-and-off car DPF cleaning
When Diesel Particulate Filters fail to self-clean, what are the other options, apart from potentially costly replacement? Rob Marshall looks at on-and-off car cleaning options to find out.
Depsite being relatively uncomplicated devices, diesel particulate filters (DPFs) tend to be misunderstood. The resultant consequences can be extremely costly and inconvenient for the car owner. Blockages tend to be the most common complaint, highlighted by a dashboard warning lamp. If unresolved, the engine will enter a reduced power limp-home mode. In extreme cases, the engine can stall and fail to restart. So, what can you do about it?
You could blame the DPF – but that could be the wrong thing to do. The DPF is a relatively simple component and a blockage is very likely to be the symptom of another problem, which you must investigate, first. Worn/dirty fuel injectors, low compression, a holed intercooler, or even a split turbocharger boost pipe will all cause the DPF to fill rapidly. While cleaning DPFs is our focus, the filter will become overwhelmed with soot again very quickly, unless you solve the underlying fault.
Once you have resolved the problem, the DPF might not clean itself, or perform an automatic ‘regeneration’ to clear accumulated soot, when you take the car for a drive. This can happen for several reasons. To protect the engine and DPF from damage, active regenerations may have been aborted.
