Fuel Additives – Are they a myth or do they actually work?

exhaust pipe with plant fuel addative

Why are the large fuel suppliers heavily promoting premium fuels with active ingredients that help to keep your engine clean? Has anything changed with the fuel we use and have engines changed so significantly over the last few years?

Fuels have changed and now have an increased amount of bio-fuel added to the mixture. The current UK level is 7% for both petrol and diesel fuels. Bio fuel is sustainable and also produces lower emissions. Bio fuel does however have down sides a; by producing slightly increased carbon adhesion and b; bio fuel gravitates water which is also not desirable for your engine.

Engines have changed significantly to reduce emissions. Diesel particulate filters, selective catalyst reducers, AdBlu and exhaust gas recirculation systems are now present on all vehicles. Manufacturers will soon be adding particulate filters to petrol cars. All of these systems reduce NOX and particle matter making our cars both greener and cheaper to tax! All of these new filter systems create back pressure and should engines start to clog, the excessive back pressure will restrict soot from exiting the vehicle and will be forced back towards the combustion system and this can also contaminate the engine oil. The new Euro 6 engines now recirculate over 80% of the combusted air. This compared to 20% for Euro 4 compliant engines means that the combusted air is now held within the engine 4 times longer!

This is why there has been a dramatic increase in the use of fuel additives in an attempt to keep the injectors in particular clean thus ensuring a clean combustion and helping to keep the fuel system from carbon build up.

There is a wide choice of fuel additives available and choosing one can be challenging at best. There are also a wide range of prices and claimed benefits for all of these products. According to the product labels they can solve a lot of problems with your car and even increase performance. But how much of that is true, and how much is just good marketing?

Virtually all additives available for purchase do not have any manufacturer approvals and are not recommended as a manufacturer technical solution. I am only aware of one producer that has fuel treatments which have passed independent tests as to their effectiveness.

The only manufacturer approved product I am aware of is the TUNAP fuel product. The Tunap product is also recommended as a technical solution by several of the UK’s largest fleets. These products have a TÜV certification having been independently tested and have proven results.

You will probably need to buy a fuel additive at some point going forward, my suggestion would be check out the price and choose wisely, it may be price versus proven results, or maybe not?


Karl is the editor and owner of this glorious website. He currently writes for numerous environmental websites, producing content for the greater good. His experience in graphic design, Wordpress and all things automotive have helped sculpt Hypermiler.co.uk into its current form from very humble beginnings. He has numerous IT qualifications, a red belt in Taekwondo and likes craft Ales. Get in touch via our Contact Page

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3 comments on “Fuel Additives – Are they a myth or do they actually work?
  1. Rob Gregory says:

    Hi Karl. My 2008 2.2 Auto Jag XType failed me last Sunday due to DPF issues. The AA came out and fitted a blocking plate. It got me 20 miles on to my destination and then a steady drive back on Cruise oup the M40 Oxford to Shrewsbury. I knew nothing about DPFs whatsoever, but will drive my Jag more like a Jag should be driven (I suppose), from now on, and increase my use of top-grade diesel too. The information on your site has been really useful and I’m grateful. (Your hindsight is spot on too)!

    • Karl says:

      Hi Rob

      Very glad you found the site useful amd also that your DPF issues have been resolved. Interested to hear more on the blocking plate. Was it an EGR blocking plate the AA fitted?

      Cheers Karl

  2. Paul V. Chandler says:

    Dear Karl, I found some information about MTBE which is active component of Tunap products. Im not sure if you have knowledge about this detail. The MTBE was compromised and stopped use as fuel additive. So Im not sure about your recommendation about TUNAP.

    I hope that this help.

    Best Regards

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