diesel particulate filter

All you need to know about Diesel Particulate Filters (DPF)


If you drive a diesel, you need to make sure you’re taking care of your DPF. This is the part of your vehicle that takes out most (and, in some cases, nearly all) of the soot from your emissions before they enter the atmosphere. If you don’t look after the DPF, it can cost you money in lower fuel economy or even in repair charges that aren’t part of a standard maintenance contract.

Here’s how to look after your particulate filter

All you have to do is get your car on an A road or motorway on a regular basis, such as every 300 miles. You then need to run it for 10-20 minutes at speeds in excess of 40mph. This will heat up your exhaust and burn off any soot in the filter.

If you don’t do this, your car may be able to deal with the soot itself, through a process called ‘active regeneration’ where it injects extra fuel to raise the exhaust temperature. You can tell when this is happening because your car’s fuel economy will drop and the engine noise will change.

The process takes around ten minutes to complete, as long as you keep your revs above 2,000. This may mean changing down a gear or two depending on where you are driving, which could then reduce your fuel economy even more.

If you don’t complete the process, or if your car doesn’t have active regeneration and you don’t burn off the soot regularly, you may need to get the DPF cleaned by a garage (costing around £100) or even have to replace it (which can cost over £1,000).

Just remember that getting rid of it is not an option. You will be committing an offence if you don’t meet emissions standards after removing the DPF. This might also invalidate your insurance and it’s an automatic MOT fail.

Five ways to look after your DPF

  1. Consider using premium
    fuel, as it is claimed this
    burns more cleanly
  2. Use the correct oils for your
  3. Make sure you check the
    oil level regularly
  4. Change your oil in line with
    the service requirements,
    as old oil may mean the
    DPF doesn’t reach the right
  5. Check which warning light
    relates to the DPF – and if
    it comes on, don’t ignore it.


If you are only doing short journeys during the COVID-19 lock-down, please consider taking a longer run on an A road once every 300 miles.


  1. Diesel

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