What is a DPF?

A DPF, or to give it its full name, a Diesel Particulate Filter is an essential piece of equipment in the vehicles exhaust system designed to minimise pollution caused by Diesel engines. Indeed, any car which doesn’t have a working DPF would automatically fail its MOT due to excess carbon emissions.

What causes a DPF to block?

Most commonly DPF’s block due to the vehicle being used on short journeys which don’t allow sufficient time for the DPF to heat up and carry out its self cleaning process known as a “Regeneration Cycle” which is where the DPF will reach temperatures of 600/800 deg c to burn off excess soot accumulation.

If the DPF is prevented from carrying out its regeneration cycle it will partially block with soot and ash and will most likely illuminate either a warning symbol or an engine management light on the dashboard.

How can it be fixed?

First and foremost, we will need to carry out a diagnostic scan using your vehicles OBD (Onboard Diagnostics Socket) this will enable us to check the actual fault status of the engine and look at live data on the engines in built sensors, along with a thorough visual inspection of related components. It is imperative that if there is a fault found then this should be rectified BEFORE any DPF cleaning takes place.

What if the DPF is found to be blocked?

It will depend on how badly it is blocked, every vehicle is different, and every job will have a unique fix, but listed below are the different solutions that we utilise.

• Diagnostics forced regeneration.

This will be in a situation where the engineer deems that the DPF has blocked with only a mild over pressure situation, typically but not exclusively around 3 to 5 psi at fast idle and will clean using the vehicles self-regeneration process of heating itself up to full temperature.

• On vehicle Terraclean chemical cleaning.

We are a licenced Terraclean agent and we have the latest in on-vehicle DPF cleaning technology. The Terraclean system is a patented process of injecting a chemical cleaning foam in to the DPF which will soften the soot build up and allow the DPF to self regenerate.

• Off vehicle cleaning

In some instances, it is necessary to remove the complete DPF from the vehicle for it to be soaked with a specialist chemical to soften the soot and ash, and then placed in our cleaning machine where air and a water-based solution are pumped through at pressures in excess of 60 psi. This process is continued until at least 95% of the soot and ash are cleaned from the DPF cannister.  This is followed by a drying process where hot air is blown through the cannister until the moisture has evaporated. The DPF is then refitted to the vehicle and all functions and adaptations are reset via diagnostics procedures.