The Best Fuel System Cleaner For Diesel & Petrol Engines

By on 2 September 2020 / Leave a comment Updated on: 17th February 2021

You might not see it; it probably isn’t something you’ve ever considered before, but how clean is the fuel that you put into your car? When you think about it, you’d never drink dirty water but your car is forced to swallow fuel, every day, that contains contaminant particles and debris. In all honestly there isn’t much you can do to prevent this. Better quality fuel may decrease the chances of contaminants but like it or not your fuel will eventually bring debris into your fuel tank and through the rest of your fuel system as it is pulled into the engine.

All the components in your fuel system including the tank, pump, lines and injectors will, over time, become coated in the debris contained within the fuel, along with the carbon deposits that form on engine parts such as valves and the combustion chamber. This happens in both petrol- and diesel-powered vehicles and will, after just a few thousand miles, begin to affect the efficiency and performance of your vehicle.

How a Fuel System Cleaner Will Benefit your Vehicle

Using a fuel system cleaner can have a multitude of benefits on how your car drives. Having the proper fuel flow returned to your vehicle can restore lost engine performance and acceleration, improve fuel economy, prevent rough running and cure uneven idling.

Clogs and blockages within your cars fuel system can not only hamper performance but can also affect reliability. An engine running with restricted fuel flow can cause damage to the vital internal components, result in hefty bills and lots of hours spent in the garage. Using one the following products could prevent issues like this arising in your vehicle.

Despite the common misconception, fuel system cleaners differ from specific injector cleaner products also available. For more information and some of the best fuel injector cleaners, check out our article.

The Best Fuel System Cleaner For Diesel Engines

STP Diesel Complete Fuel System Cleaner

stp complete diesel fuel system cleaner

Check the latest price on Amazon

The first of our diesel fuel system cleaner products comes from the industry leading brand STP. Their diesel fuel system cleaner promises to clean the entire system, from tank to engine with just one application, recommending to re-administer every 4000 miles in order to keep the system in perfect shape and prevent build-ups and future issues from occurring.

As the additive passes through the fuel system it will clear the deposits left within the tank, fuel lines, injectors and some of the engine internals. This, they promise, will result in a better running engine that not only re-establishes lost performance but also allows fuel consumption to be reduced and correct emissions levels to be restored (particularly important for your MOT).

Debris being removed from the fuel system can help to prevent corrosion due to moisture being trapped on the surface of metal parts within the engine. This simply applied product could prevent internal engines woes and huge repair bills, for minimal outlay.


  • Clear debris build up from engine internals
  • Restore lost performance and fuel economy
  • Reduce harmful emissions
  • Prevents moisture build-up and corrosion


  • More expensive than Redex diesel system cleaner
  • No promises of compatibility with biodiesel vehicles

Redex Diesel System Cleaner

redex diesel system cleaner

Check the latest price on Amazon

Redex is no doubt a brand you’ve seen before, their products sell well, particularly here in the UK. You can find their products everywhere from online to your local supermarket. Their diesel system cleaner is another of the company’s popular products (alongside the petrol variant outlined below) and promises some fantastic benefits for your diesel vehicle.

Using this product and giving your fuel system a full clean out will save fuel and restore lost performance caused by clogged and inefficient fuel delivery to the engine. The formula promises to remove debris and harmful deposits that build up around the fuel system including the injectors.

Having your fuel system running at optimum efficiency can also reduce the emissions from the exhaust (important for your MOT). A properly flowing fuel system will not only give increased performance. The benefits of proper fuel flow will give an increase in reliability, with less chance of fuel starvation causing poor running or failure to start.


  • Least expensive diesel system cleaner listed
  • Restore lost performance
  • Reduce emissions
  • Improve long-term reliability
  • Handy “shot” marker on the side to show amount needed per tank


  • Required to use regularly to keep fuel system clean
  • Cannot use with biodiesel vehicles

BG 244 Diesel Fuel System Cleaner

bg 244 diesel fuel system cleaner

Check the latest price on Amazon

BG are not as well known as their rivals but have great experience in the DPF cleaning sector and have in the last few years, started offering a whole range of vehicle additive products. The company specialises in creating industry tested formulas that outperform their rivals and offer a more professional level of product for the general public.

Their 244 diesel-specific fuel system cleaner aims to remove carbon deposits through the entire fuel system, including the engine internal parts such as valves and injectors. The cleaner is also safe for any diesel vehicles, including those fitted with diesel particulate filers and catalytic convertors.

The removal of carbon deposits will give restored performance to your diesel engine, while reducing fuel consumption and lessening the amount of harmful emissions. Regular use of the product can also lead to a reduction of the deposits on your DPF, making this a great product to both clean the fuel system and DPF simultaneously without the need for multiple products.


  • Only requires use every 10,000 miles
  • Remove carbon build up on engine internals
  • Clean the DPF simultaneously
  • Improve fuel consumption
  • Restore lost performance


  • Most expensive diesel-specific system cleaner listed
  • Less well-known brand

The Best Fuel System Cleaner For Petrol Engines

STP Petrol Complete Fuel System Cleaner

stp complete petrol fuel system cleaner

Check the latest price on Amazon

The first of our petrol fuel system cleaners comes from STP. Their petrol-specific product promises very similar benefits to the diesel fuel system cleaner, as you will find with most brands. The difference is in the formula, in that the product will aim to remove debris and build-up caused more often in petrol engines, rather than those found commonly in diesel powered vehicles.

STP’s petrol fuel system cleaner promises a comprehensive fuel system clean from a full bottle application, with regular application every 4,000 miles recommended to upkeep the performance of your vehicle and to reap the maximum possible benefits. The cleaner will remove deposits from internal engine parts such as valves, injectors and the combustion chambers.

Removing harmful deposits will restore lost performance to your vehicle, solving issues with hesitation and power loss that are common place among vehicles with fuel systems that are underperforming. The results should also show reduced fuel consumption and help to prevent internal engine components becoming corroded due to moisture being trapped on metal parts.


  • Reduce likelihood of corrosion
  • Improve fuel efficiency
  • Remove build-ups and deposits including those on internal engine parts
  • Reduce emissions and fuel consumption


  • Full bottle required for fuel system clean
  • More expensive than Redex petrol system cleaner

Redex Petrol System Cleaner

redex petrol system cleaner

Check the latest price on Amazon

Another petrol-specific fuel system cleaner is this offering from Redex. As per their diesel fuel system cleaning product, Redex promises great benefits for your vehicle, from a highly trusted brand here in the UK.

The petrol system cleaner will remove build-ups and deposits that exist within your cars fuel system and injectors specifically. The product is added simply into your tank using their “dose” system that separates the Redex product from rival brands in that it shows the exact amount required per tank of fuel.

Cleaning the fuel system and injectors will result in performance being restored, while reducing fuel consumption and harmful exhaust emissions. Reducing emissions could help come MOT time, while the cleaning of internal engine parts could save you from future garage trips, thanks to improved reliability and a smoother running engine.


  • Cheapest petrol fuel system cleaner listed
  • Trusted brand
  • Improve reliability
  • Restore lost performance
  • Handy “shot” marker on the side to show amount needed per tank


  • Need to regularly re-apply to keep optimum performance

BG 44K Fuel System Cleaner

bg 44k petrol fuel system cleaner

Check the latest price on Amazon

Like their diesel-specific offering, BG has focused on ensuring their 44K cleaner matches up to their professional standards, offering a higher level of clean than rival products, though coming in at a higher price point. Unlike competitors’ offerings, BG’s fuel system cleaner contains high levels of Polyether Amine, which is proven to remove hard, baked-on carbon deposits within your engine.

BG 44K cleans not only the fuel system but also internal engine components such as valves and injectors, as well as having a positive cleaning effect on exhaust parts such as the catalytic convertor and 02 sensors. Reliability of your engine will be improved, the removal of deposits will be minimising the likelihood of problems with injector clogging, misfiring and erratic idle.

Results of just one application will be improved fuel economy and restoration of lost power. BG 44K is suitable for use in both petrol and diesel vehicles as well as those that are equipped with DPF’s, turbochargers and catalytic convertors. It can even be used for agricultural, marine and commercial-use engines.


  • Cleans catalytic convertor and O2 sensors
  • Suitable for petrol and diesel vehicles
  • Reduce likelihood of fuel system-derived reliability issues
  • Improve fuel economy
  • Restore lost performance
  • Professional level additive, industry tested


  • More expensive than most rivals

In Conclusion

Manufacturers design vehicles and their fuel system to work at a certain rate, allowing for maximum efficiency, optimum performance and minimum emissions (often to meet increasingly strict EU standards). Fuel components with debris hampering their performance will cause your vehicle to run less than optimally and could affect reliability down the road.

These simple fuel system cleaning additives can restore the performance and reliability that you would expect from your vehicle, without the need for dismantling or garage services. They are available for a minimal outlay and are simply added into your fuel tank, for a full system clean before being safely burned in combustion and expelled via the exhaust. Clearing and preventing future debris build-ups could keep your car on the road and improve your driving experience dramatically, within the space of just a couple minutes. Don’t let your car suffer, pick up one of the products above and prevent the issues before they occur.

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Jack Gill

Car journalist and fully qualified mechanical engineer, Czok’s newest contributor and long-time automotive writer. Lifetime passion for all things automotive, from new supercars to rusty old hatchbacks. If I’m not behind the wheel, I’m likely under the bonnet or browsing the classifieds. Having spent over 5 years in the automotive industry and under the bonnet of my own car at home, I want to share the knowledge and learning that I have gained, with others without the time to study or the expertise, who just want their car to get them from A to B every day. We aren’t all interested in trawling through endless internet pages and forums. I aim to gather all the information up and roll it into a quick summarised format, to give only the information you really need.

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