Why Does My Diesel Particulate Filter (DPF) Block?

There are several reasons why DPF’s get blocked.

The main reason is that the vehicle’s own temperature- based regeneration mechanism hasn’t been initiated. The car’s DPF needs a temperature of around 600°C in order to burn off the soot in the DPF and turn it into smaller-particle ash which is more easily expelled from the exhaust. Taking the vehicle on an extended run of over 15 minutes at approximately 3000 rpm is usually sufficient to trigger the vehicle’s own regeneration. If, however, the vehicle is only subject to short, perhaps urban, journeys, it may never get up to the required temperature.

Using the wrong engine oil for your specification of vehicle can also cause an additional build- up of soot. A low-ash oil is usually appropriate.

The use of bio-fuels often accelerates the build- up of soot as it does not burn as cleanly as regular diesel fuel.

Higher mileage diesel vehicles often struggle to complete the regeneration cycle, simply because of the age of the DPF, and the naturally deterioration that occurs with ageing parts on vehicles. So, in the above cases the DPF may well require cleaning intervention.

The ‘reverse-flush’ process that we use at Darwen Diesels is cost effective and cleans a DPF to 98% of its original ‘new’ state. This is evidenced with a print-off report, highlighting before and after results.