DPF regeneration without paying a mechanic


Two steps to getting your car back to full health

DPF filter cleaning for just a few pounds

Order Forte Diesel DPF Cleaner

Depending on your car type, driving with a faulty DPF filter can be illegal.

Motorists tend to avoid repair due to the expense of cleaning, remapping or replacing the filter, particularly if the car still runs pretty well but there is an engine warning or glow plug light flashing.


Prices can exceed more than £750 + VAT

Diesel particulate filters (DPF) are placed on the exhausts of diesel vehicles to prevent toxic emissions from flowing into the environment. Despite this, some motorists have the diesel filter removed to avoid mechanic failures and additional maintenance costs.


exhaust system and dpf filter functions


Here, I provide a two-step guide to regenerating a DPF filer for pennies, without the need for a mechanic

Some facts:

  1. More than 3,000 UK motorists have been caught driving a car without a DPF
  2. Campaigners are voicing complaints to the Advertising Standards Agency (ASA) regarding the spike in DPF filter removal. Such ads are deemed to be breaking the ASA code of conduct that condones practices that encourage anti-social behaviour. It’s alleged that such ads are exploiting a loophole in the law which clearly states that driving a diesel vehicle on the road without a DPF is an offence, but the actual removal of the filter is not.


Over the last 10 years, air pollution has become a public health emergency and it is further alleged that particulate pollution is now responsible for around 50,000 avoidable deaths every year in the UK.

Put the numbers to one side and notice that hundreds of car repair garages continue to offer the removal of DPF filters. MP’s are labelling this practice as ‘detrimental to people’s health’ and ‘unacceptable’.



Why remove DPF’s?

It’s mostly a cost saving exercise as filters easily become clogged up, especially with city driving where vehicles are driven at slow speeds in residential areas.

A lack of motorway driving is one cause of clogged filters that can only lead to mechanical problems and/or engine warning lights flashing continuously.

Since 2014, any diesel vehicle missing a diesel particulate filter will automatically fail its MOT. The Guardian newspaper revealed that thousands of drivers have been caught without a DPF fitted to their vehicles.

However, some MOT stations are posting on their websites that they can beat the visual MOT DPF check.



Friends of the Earth (FoE)

Founded in 1971, FoE is a federation of 74 groups from all over the world who are dedicated to saving the environment. One of their primary causes involves complaining to the ASA about the prevalence of adverts for DPF removal services.

In a press release from 2 May 2016, FOE air pollution campaigner, Oliver Hayes, stated, “Air pollution is a public health crisis of breath-taking proportions. The dodgy practice of removing pollution filters from cars is not only risking people’s health but also putting drivers at risk of prosecution for the simple fact that it’s illegal to drive a car with its DPF removed.”

He went on to say, “We’re asking the ASA to clamp down on those advertising these dubious practices … But we’re also calling on the Government to make it illegal to remove these pollution filters in the first place”.

Chaired by Mary Creagh MP, the House of Commons Environment Audit Committee is currently investigating diesel emissions and air quality. She states, “The Department of Transportation did the right thing in introducing visual checks into MOTs. But it should now look at tightening up MOTs and outlawing the removal of pollution filters altogether”.



2 Step guide to DPF filter cleaning

No mechanic required

In 2016 I bought a Vauxhall Zafira diesel automatic, with a DPF filter fitted as standard. As I was driving the car from Southampton to Bristol the engine glow plug light began flashing. Different cars will illuminate different warning lights as you can see in the image below.

The car was running just fine, although it was drinking a lot of diesel. The only other symptom was a flashing glow plug light.


dpf engine warning lights


My mechanic diagnosed that the DPF filter was faulty and needed replacing. The trade cost to supply and fit the filter was £918 + VAT. This cost was going to eat all profit when I sold the vehicle.

As mentioned, DPF Filters easily block and degenerate when a car is primarily driven around town and doesn’t get a good motorway run from time to time (preferably every couple of weeks).

My Zafira was in excellent condition and may have been previously owned by a very careful driver that rarely revved the engine.

This led me to attempt my own DPF unblock, without touching a spanner


You may have heard that you can regenerate a DPF Filter by giving the car a run down the motorway. This rarely works because the car filter is so badly blocked that a replacement may seem to be the only remedy.



How to unblock almost any DPF Filter

Here’s how I permanently unblocked the DPF on my Vauxhall Zafira (and other diesel cars too)


clogged DPF filter


If you follow my instructions, you are likely to clean and unblock your car filter with no need for replacement or excessive repair costs.



Step 1

Go to Amazon and specifically buy “Forte Diesel Fuel System Treatment & DPF Cleaner & Turbo Cleaner Package”.


Fuel System Treatment & DPF Cleaner


This product is the only one that works (I’ve used the others without success). It’s a bit more expensive than STP, Archoil and Wynns but for good reason. Seriously, I’d only buy the Forte DPF additive. Amazon have a next day delivery option here

Follow the simple instructions to apply the DFP cleaner. Once you’re done move on to the second step below.



Step 2

Drive your car exactly as I describe below:

After using your DPF treatment head to the motorway and drive your vehicle at extremely high revs for at least 30 minutes.

By high revs I mean at least 5,000 RPM.

It can be a little unnerving to hear your engine working so hard, but, it works.


Manual gearbox

If you have a manual car I suggest second gear and a speed of around 50 mph or you can try third gear at around 80 mph.

Automatic gearbox

If you have an automatic select the auto second gear position and drive the engine around 5,000 rpm.



It’s very important that you consistently hold the revs and speed for at least 30 minutes (preferably more.) If you do this correctly your filter will almost certainly unblock itself.



Once you have run the car very hot for a sustained period pull over and immediately switch off the car.

Wait for five minutes before restarting your car to find that the DPF warning light, glow plug light or engine management light switched off!

By running your car in this manner, you regenerate the DPF Filter and unclog all the soot and dirt that’s built up over time.

Please ensure you have got the correct, sufficient engine oil in the car before using this method.


Note – Once your car is back to its old self it’s important to give it a good blast at least weekly or the light will come back on in the future.


The Used Car Guy holds no liability for your outcomes when trying the procedure listed above. This article is meant only to aid car owners that wish to avoid spending large amounts of money on their used car.

Used Car Guy



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Step 1
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Follow step 2 outlined in this guide

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