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The best diesel engine cleaners

  • Get rid of build-up carbon deposits
  • Additives to clean injectors, turbos and more
  • Improve performance with Cataclean, STP and Wynn's

Written by Ryan Gilmore Published: 22 December 2022 Updated: 6 December 2023

Diesel engine cleaners are still a mainstay of the car care routine of diesel owners despite diesel cars being in decline across the UK, but they still remain a solid choice if you’re regularly doing long journeys. Not much can come close to diesel in terms of motorway fuel efficiency, and there are still plenty of diesel vehicles available, both new and used.

One issue that plagues diesel, however, is the build-up of carbon deposits over time. It’s a perfectly natural occurrence and shouldn’t do lasting damage, but affects your engine’s efficiency. Diesel cars lose power, emit more harmful emissions and use more fuel if these deposits go unchecked. A number of engine components are affected; injectors, turbos and emissions equipment can all suffer at the hands of carbon deposits.

Thankfully, there’s a simple solution. A diesel engine cleaner will remove these deposits and allow you to enjoy the full potency of your diesel car. The best part is that the majority of them are fuel additives, meaning you just bung it in your fuel tank (with regular diesel) and simply drive around as normal to clean your engine out. Join Parkers as we guide you through the best diesel engine cleaners currently for sale.

The best diesel engine cleaner

Editor's choice

Rrp: £17.49

Price: £15.62
If your main concern is reducing engine emissions, then Cataclean is your best bet. Designed to clean and protect your car's catalytic converter and DPF (diesel particulate filter), it will help reduce nasty pollutants from entering the air.


  • Reduce emissions
  • Increase fuel economy


  • Difficult to notice improvements in performance
On sale

Rrp: £18.99

Price: £13.69 was £18.99
Amazon Amazon Prime
Alternative Retailers
If you want to give your diesel engine a total blitz, the STP 5-in-1 additive is an excellent option. Pour it into your fuel tank and it'll start removing buildups from your engine. The 5-in-1 also works as a preventative measure against further deposits building up.


  • Great for removing deposits
  • Improves engine power


  • MPG boost is debatable
Best diesel engien cleaner for turbochargers

Rrp: £6.99

Price: £6.50
Turbo-diesel engines are very popular these days because they offer greater power while still being very efficient. Sadly, even turbochargers aren't immune from blockages, so this turbo cleaner will be invaluable. It'll restore a good chunk of power, just make sure your car comes with a turbocharger first.


  • Helps restore performance
  • Saves turbochargers from expensive repairs


  • Only works with turbo diesel engines

Crucial engine cleaning

Best diesel engine cleaner for injectors

Rrp: £18.99

Price: £17.40
Injectors are one of the first things to clog in diesel engines and will affect performance and fuel economy noticeably. This offering from Forte Lubricants will clear your injectors for better power. It is also formulated to help diesel engines when cold, perfect for January in the UK.


  • Formulated to help with cold conditions


  • Won't help anywhere else
Best diesel engine cleaner for EGR systems

Rrp: £7.46

Price: £5.99 was £7.59
Amazon Amazon Prime
The Exhaust Gas Recirculation (EGR) system reduces harmful Nitrogen Oxide emissions (NOx) helping the planet. Unfortunately, particulates can stop this from working which will increase harmful emissions. This aerosol from Wynn's is designed to clear the EGR valve, air intake system and inlet valves, helping your engine be as efficient and harmless as possible.


  • Reduces harmful emissions
  • Avoid hefty EGR repair bills


  • Will not help performance
On sale

Rrp: £12.49

Price: £9.59 was £12.49
Amazon Amazon Prime
A diesel particulate filter (DPF) is an emission device that removes harmful soot emissions from entering the atmosphere. While these help the planet, they also get clogged up really easily and will strangle performance and hurt fuel economy. This particulate cleaner will remove these soot emissions, making your engine run smoother and cleaner.


  • Reduces soot emissions
  • Avoid DPF maintenance costs


  • Doesn't target other areas of the engine
Best diesel engine cleaner for high milers

Rrp: £6.49

Price: £5.99
Amazon Amazon Prime
If you're running a high-mileage diesel car, then you'll have age-related issues to deal with on top of the usual deposit problems. This additive from STP is formulated to both remove stubborn deposits and boost engine power while also protecting your engine from excessive wear.


  • Perfect for cars with over 75,000 miles on the odometer
  • General engine care


  • No use on lower mileage cars

When should I use a diesel engine cleaner?

Diesel engine cleaners, also known as diesel fuel additives or injector cleaners, can be used to improve the performance and efficiency of diesel engines and to help them last longer. Periodically adding a diesel engine cleaner to your fuel tank should be part of your routine maintenance and can help prevent carbon build up in the injectors and keep the engine running smoothly.

Other times to use a diesel engine cleaner include:

Fuel System Issues: If you’re experiencing symptoms like rough idling, poor fuel efficiency, excessive smoke, or reduced power, it may indicate issues with the fuel system, such as clogged injectors or a dirty fuel filter. In such cases, a diesel engine cleaner can help clean the injectors.

Cold Weather: In cold climates, diesel fuel can gel and cause problems in the fuel system. Some diesel additives include anti-gel properties to prevent fuel from gelling at low temperatures.

Biofuel Blends: If you’re using biodiesel or other biofuel blends, a diesel engine cleaner can help mitigate issues related to water and microbial growth in the fuel system.

Emissions Testing: A diesel engine cleaner can help reduce harmful emissions and improve the chances of passing MOT emission tests.

Fuel Economy: If you’re looking to improve fuel efficiency, some additives claim to enhance combustion and increase miles per gallon (MPG).

Older Engines: Older diesel engines may benefit from engine cleaners to remove carbon deposits and improve overall performance.

When using a diesel engine cleaner, it’s important to follow the manufacturer’s recommendations for the specific product you choose. Different products have different formulations and purposes, so be sure to read the instructions and dosage recommendations on the product label. Additionally, be aware that not all engine cleaners are created equal, so it’s important to choose a reputable product from a trusted manufacturer.

Keep in mind that regular maintenance, including changing fuel filters and using high-quality fuel, is also crucial for keeping your diesel engine running smoothly.

Ryan Gilmore is the Deputy Autos and Tools Editor for Parkers, specialising in car cleaning and hand tools. A veteran car cleaner; if it details, waxes or washes he’ll be on hand to make sure it’s worth your money.

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