We’ve all watched as a car has driven past us with smoke billowing from the exhaust pipe. We feel the fear on behalf of the other driver, combined with a notable feeling of relief:   

“I’m glad that’s not my car.”

The thing is, sometimes it is your car.

No matter how hard we try, problems can occur when we least expect it, and they can happen to parts of our cars that we didn’t even know existed until they started to fail.

Do you own a diesel car? Have you ever heard of a diesel particulate filter - otherwise known as a DPF - before? If you answered no, then you’re certainly not alone.

In this article, you’ll find out how a DPF works, what could be blocking it, and what you can do to fix this. Read on and learn for yourself how you can avoid DPF problems.


How Do DPFs work?

If you drive a diesel car that was built after 2009, then it will have a diesel particulate filter (DPF). This clever car part works to trap the soot produced by your car when diesel is burned off. This helps to reduce the harmful emissions that your car produces, by preventing them from entering the atmosphere.

Unfortunately, as this soot level builds up over time, your DPF will become blocked if you aren't careful. Other than taking your car in for a professional DPF cleaning, your car needs to go through a process known as regeneration in order to burn off this soot. Regeneration can be active or passive, but both types are an attempt to raise the temperature of your exhaust to target the soot. A layer of ash will remain even after regeneration, and this in itself can cause problems for your DPF, as it hardens over time. 

You will be able to tell that your DPF is blocked if you notice any of these warning signs:

  • A loss of performance or power
  • Your car's DPF regeneration cycle is failing or not finishing
  • A rising oil level
  • Your car is using more fuel than normal
  • Heavy smoke
  • You can smell diesel

If you remain aware of these problems, you could prevent the need for an expensive DPF replacement. Instead, your car may be in dire need of a DPF clean, particularly if you haven't booked one in a while. Your car’s DPF warning light will shine and let you know once your DPF is almost 70% full of soot, at which point your car’s performance will be limited.

To ensure that this level doesn't increase - your DPF will need replacing once you hit 90% - it is definitely worth booking a DPF clean every 6 to 9 months.


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Will a Blocked DPF Damage My Engine?

A blocked DPF can cause severe damage to your engine. This is because your engine is having to work a lot harder to vent the exhaust fumes that your blocked DPF is failing to. This can lead to weakened acceleration, increased fuel consumption, and the risk of leaks.

DPF cleaning can improve your car’s performance, by taking this pressure off of the engine. If you neglect this filter for long enough, you could see other issues, like melted filters, low vehicle power, and your DPF itself may even crack. Whilst you can buy DPF cleaner designed to flush out the insides of your car when regeneration cannot be completed, this won't help to unblock a significantly blocked DPF.

A professional DPF clean is the best option if you really want to notice a difference in the quality of your car's diesel particulate filter. 


Am I Allowed to Remove a Blocked DPF Myself?

It is illegal to change your DPF yourself, or to drive without one in the UK. Not only should you never remove a DPF yourself, but you should know that driving a car without a diesel particulate filter that was fitted with a DPF when it was first built can result in MOT failure.

The smart thing to do would be to have your filter cleaned by a skilled mechanic and save yourself the hassle of a failed MOT and a potentially expensive DPF replacement. These can cost up to £3,000!


How Long Does It Take to Unblock A DPF?

When you take your car to a professional garage for a DPF clean, the whole process can take up to 2 hours to complete. An expert mechanic can put your DPF through a process called forced regeneration.

During this process, a mechanic will be able to burn away the soot particles in your diesel particulate filter.


How Much Does a DPF Cleaning Service Cost?

When you book in for a DPF cleaning service through BookMyGarage, this can cost you as little as £99. This includes a full inspection, diagnosis and flush, all performed by highly-qualified mechanics. By booking a DPF clean, you can get your car in the best shape possible in time for its next MOT.

Keep fuel costs to a minimum and expensive DPF replacement costs at bay - book in for a DPF cleaning service today!


Book online today!

Don't know your vehicle registration?