DPF Cleaning Guide: How to unclog your diesel car
(and your wallet?)

Authored by Marcus Rockey, covering the automotive sector for more than 30-years – with a focus on private motorists buying or selling a used car. Published 10th September 2023.

How to privately sell my car.

Most times, cleaning your car DPF filter is pricey.

A cheap fix (depends on make and model and local mechanic) starts around £350 + VAT.

Some cars cost more, and you might get priced out at £1000 +.

As a first step, you can look at a DPF cleaning agent like Forte or STP, and try to clean the filter yourself, but it’s hit-and-miss.

Our sister site, Clickmechanic (with thousands of positive Trustpilot reviews) will fix your car at the cheapest prices possible. We can also collect your car, make repairs (including parts and labour) and deliver back to your home or work address.

See here for a no obligations online quote.

How to tell if the diesel particulate filter is blocked

If your car has any of the symptoms listed below, your car may have a clogged Diesel Particulate Filter (DPF):


  • DPF Warning light displaying on the dash
  • Glow plug light flashing on the dash
  • Engine isn’t running smoothly or is underperforming (Limp Mode)
Glow plug and DPF warning light odometer displays.

You have two options to fix your car:


  1. Clean the filter yourself using a DPF cleaning solution (The cheapest method and may work for your vehicle depending on the extent of the sediment/blockage).
  2. Use a DPF filter cleaning service – more reliable but more costly. Use a reputable garage for repairs. We recommend Clickmechanic with over 12,000 reviews and a 4.6 rating on Trustpilot. Get a simple online quote without needing to book

A professional service such as Clickmechanic typically sets you back between £350 and £1,000 plus VAT and assures your vehicle will be repaired and in tip top mechanical condition.

About DPFs

Despite the UK’s zero emissions initiative, diesel vehicles remain popular for UK motorists, especially since diesel fuel prices are now on par with standard unleaded fuel prices.

All modern diesel vehicles (post-2009) are built with Diesel Particulate Filters (DPFs).

DPFs are responsible for reducing the emissions and harmful particles produced by diesel engines, ensuring they meet environmental standards for cleaner air.

As a diesel engine owner, it’s essential to understand the importance of a DPF and how to maintain it properly.

DPF cleaning is a vital aspect of maintaining your diesel engine. Over time, soot accumulation and other particles in the filter can lead to reduced performance, engine damage, and even failure to pass an MOT test.

Mechanical issues on modern diesel engine vehicles

The DPF often blocks up when a vehicle is mostly driven around town on frequent short journeys. Diesel engines like a good motorway run that allows for the mechanical regeneration process.

Without natural DPF regeneration, sediment and clogging usually occur, leading to a blocked filter.

Key Takeaways

  • Regular DPF cleaning is essential for maintaining diesel engine performance.
  • Various methods and products are available to clean your filter effectively.
  • Proper maintenance and prevention help extend your DPF’s lifespan and minimise emissions.
Schematic of a standard DPF filter.

Step 1

Understanding DPFs

How Does a DPF Function

The DPF uses a honeycomb structure to trap soot particles from the engine’s exhaust gas. Over time, these particles accumulate and need to be burned off through a process called regeneration.

Active regen

Active regeneration occurs when your vehicle’s engine management system injects additional fuel into the combustion cycle to raise the exhaust gas temperature, ensuring optimal DPF cleaning.

Passive regeneration, on the other hand, occurs during longer drives at higher speeds, where the naturally increased exhaust temperature is enough to clear the DPF. Maintaining the DPF to keep your vehicle running efficiently and prevent costly damage is essential.


Indications of a Dirty DPF

To avoid issues with your DPF, watch out for the following signs:

  • Warning lights: Your vehicle’s instrument panel may display a warning light, usually in the shape of a filter or exhaust system. This is an indication that your DPF needs attention.
  • Reduced engine performance: A dirty DPF can restrict exhaust gas flow, causing a lack of power (including Limp Mode) and reduced performance in your vehicle.
  • Poor fuel economy: When your DPF is clogged, regeneration cycles become more frequent, increasing fuel consumption.
  • Unusual sounds: If your DPF is not functioning correctly, you may hear a change in your engine’s noise, such as a rattling or a low rumble.

It’s essential to address DPF issues promptly to avoid damage to the filter and other components. Regular DPF cleaning is the best way to maintain and check vehicle performance and help prevent future problems.

Cleaning DPF filter with engine cleaners or hiring a professional mechanic.

Step 2

The Cleaning Process

DIY Blocked DPF Cleaning using DPF cleaning products

If you’re keen on tackling your diesel particulate filter (DPF) cleaning by yourself, you can follow some simple steps to improve its efficiency.

First, ensure your vehicle is parked in a well-ventilated area and give the engine enough time to cool down completely.

Cleaning the filter through the regeneration process

It’s said that a consistently high-revved engine can remove excess soot and trigger self-regeneration.

Some mechanics claim that holding the car at four or five thousand revs for a prolonged period can clear blockages and cure the DPF blockage.

If you’re going to try this method, also use a reputable DPF cleaning product like FORTE DPF Cleaner and Regeneration or STP GST66200EN Diesel Particulate Filter Cleaner. Both products are less than £20 to buy on Amazon.

Removing the DPF yourself (for those with mechanical experience)

To begin cleaning, remove the DPF from your vehicle, following the manufacturer’s guidelines.

Use a specific DPF cleaning solution, available at most automotive stores, and spray it generously onto the filter. Let it soak in for about 20 minutes, giving the solution time to break down the accumulated soot.

Afterwards, rinse the DPF thoroughly with water, using a pressure washer if possible. Allow it to completely dry before reinstalling it in your vehicle.

Finally, take your vehicle for an extended drive, ideally at highway speeds, to burn off the remaining soot and to ensure the cleaning solution is thoroughly expelled from the system.


Professional DPF Cleaning Service

Opting for a professional DPF cleaning service can save you time and give you peace of mind that your filter is performing at its best.

Find a reputable service provider like ClickMechanic with experience handling diesel particulate filters.

Professional methods can include state-of-the-art ultrasonic cleaning or a more comprehensive fluid-based process.

The DPF removal is usually submerged in a tank filled with a cleaning solution during an ultrasonic cleaning. Ultrasonic waves create microscopic bubbles that effectively remove accumulated soot and ash.

Fluid-based methods involve high-pressure water with specialised cleaning agents to break down and flush away soot and debris.

Both methods ensure a thorough cleaning of your DPF, but it’s worth discussing which is most suitable for your vehicle with the professional service provider.

They will also perform diagnostic tests to assess the overall health of the filter before and after cleaning.

Remember that regular maintenance, such as oil changes and servicing, can help prevent DPF problems in the first place.

Ensure you follow your vehicle manufacturer’s recommended maintenance schedule and adhere to any warning signs your vehicle may provide regarding DPF performance.

Cleaning and maintaining DPF filters.

Step 3

DPF Maintenance Clean and Prevention Tips

Regular Services

To ensure your Diesel Particulate Filter (DPF) remains in good condition, it is essential to have your vehicle serviced regularly. This includes oil changes, fuel filter replacements, and air filter maintenance.

Keeping your engine in peak condition can reduce the chances of DPF blockages.

Here are some general guidelines for regular services:

  • Oil change: Every 10,000 miles (16,000 km) or 12 months, whichever comes first
  • Fuel filter replacement: Every 20,000 miles (32,000 km) or 24 months, whichever comes first
  • Air filter maintenance: Check and replace as needed during routine servicing

Using high-quality fuel and compatible engine oil will also help in DPF maintenance.


Preventing a dirty DPF

There are several ways you can help prevent DPF blockages and issues, such as:

  • Avoid short journeys: Short journeys do not allow the engine to reach optimal temperatures, hindering regeneration. Try to combine trips and aim for longer drives occasionally to help the DPF regenerate.
  • Keep an eye on warning lights: If your vehicle displays a DPF warning light on the dashboard, it indicates the filter is blocked. It is crucial to address this issue promptly by driving steadily for approximately 15–20 minutes to initiate active regeneration.
  • Manual regeneration: Some vehicles are equipped with a manual regeneration feature. Consult your owner’s manual for instructions on how to initiate this process if needed.

Remember, following these maintenance and prevention tips can help keep your DPF in great working condition and avoid costly repairs.

DPF specialist cleaning.

Step 4

Consequences of Neglect

Impact on Vehicle Performance

Neglecting your vehicle’s Diesel Particulate Filter (DPF) cleaning can significantly impact its performance.

Over time, your engine may experience a loss of power, reduced fuel efficiency, and increased exhaust emissions.

You might notice a decline in acceleration responsiveness or even face your vehicle entering a limp mode, limiting its speed.

Paying attention to DPF warning lights on your vehicle’s dashboard is essential. Ignoring these signs can lead to severe consequences, such as complete engine failure or costly repairs.

Regularly scheduling DPF cleaning can help maintain your vehicle’s overall performance and keep it running smoothly.


Environmental Impact

The primary purpose of a DPF is to capture and remove harmful particulate matter from diesel exhaust emissions.

If you neglect the cleaning and maintenance of your DPF, these particles will accumulate and eventually be released back into the environment.

This situation results in an increase in air pollution, contributing to poor air quality and associated health problems.

In addition, a clogged DPF may cause your vehicle to consume more fuel, leading to increased CO2 emissions.

These greenhouse gases directly contribute to climate change and can have severe environmental consequences.

Proper maintenance of your DPF, including regular cleaning, ensures that your vehicle operates as efficiently and cleanly as possible.

This practice helps reduce your vehicle’s environmental impact and supports overall efforts to improve air quality.

Step 5

Key takeaways

Take DPF cleaning seriously and maintain your vehicle’s performance, reduce harmful emissions, and avoid costly repairs.

Understanding how the DPF works allows you to identify the warning signs and follow necessary cleaning steps easily.

Regularly check your DPF indicator light on the dashboard. If illuminated, it indicates it’s time for a DPF clean.

Keep in mind that driving at higher speeds for extended periods can be effective in promoting passive regeneration.

In some cases, you may need to opt for professional cleaning services. Ensure you choose a reputable service provider with experience handling DPF cleaning for your vehicle make and model. We recommend Clickmechanic.

By investing a small amount of time and effort in DPF cleaning, you can:

  • Safeguard your vehicle from expensive breakdowns and future issues
  • Boost your vehicle’s performance and fuel efficiency
  • Minimise your carbon footprint by reducing harmful diesel emissions

In the long run, regular and thorough DPF cleaning will pay dividends in the form of better engine performance, increased fuel efficiency, and an overall healthier and environmentally friendly driving experience.

Stay informed, follow the recommended practices, and always seek expert guidance when needed.

A proactive approach to DPF cleaning will ensure your vehicle remains in optimal condition for years to come.