There's a fairly common and costly fault in modern diesel campervans, and the curious thing is that it's encouraged by exactly the kind of use many campers get: short trips at low speed. We're talking about the diesel particulate filter, or DPF. Understanding how it works helps you look after it and avoid a hefty bill. Here's a clear explanation.
What the DPF is
The diesel particulate filter (DPF) is an exhaust component that traps the soot particles produced by a diesel engine, so they aren't released into the atmosphere. Over time it fills up with soot and needs to "clean itself" periodically, in a process called regeneration.
The problem: regeneration needs a good run
This is the key point. To regenerate (burn off the accumulated soot), the DPF needs to reach high temperatures, which happens when the vehicle runs for a good while at sustained speed (for example, on a motorway or dual carriageway). The problem for many campers:
- Short, urban trips (lots of stopping, low speed) don't heat things up enough for the DPF to regenerate properly.
- The vehicle sitting parked for long periods (campers do relatively few miles a year) builds up pending regenerations.
- Result: the DPF gradually clogs up, the warning light comes on, the vehicle loses power and, if nothing is done, it can end up needing an expensive repair or replacement.
How to look after it
- Give it a "proper run" now and then: if you do lots of short trips, mix in some sustained-speed driving (a motorway run, for example) to let the DPF regenerate.
- Don't cut a regeneration short: if you notice the vehicle is regenerating (you can sometimes tell), try to keep driving until it finishes, rather than switching off as soon as you stop.
- Act on the DPF warning light as soon as it appears; the sooner you deal with it, the better.
- Use the right fuel and oil and keep up with maintenance.
In summary
The DPF traps diesel soot and needs to regenerate by running at sustained speed; the short trips typical of many campers clog it up and can cause an expensive fault. The step you can take today: if you mostly do short trips, give your camper the occasional motorway/dual-carriageway run so the DPF can regenerate, and act on the warning light as soon as it appears; prevention is far cheaper than repair. Combine it with the maintenance checklist.