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Do Fuel and Oil Additives Really Work?

by Andy Published on Thursday, May 30th, 2013

Firstly, we need to understand what is meant by “work” as there are conflicting ideas and interpretations. Some would consider “work” to improve performance or increase mpg, whereas others would consider “work” to clean the fuel system, restore fuel injector efficiency or reduce friction. Others would consider a product to have “worked” if it resolved an underlying problem, such as resolving engine hesitation, restoring lost performance, or reducing excessive emissions.

So which is correct? Firstly you need to understand how additives work and what they really do:

Fuel additives directly deliver one or more of the following:

1. Clean the fuel system and restore injector efficiency
2. Remove combustion deposits
3. Help clean emissions control system components
4. Lubricate the fuel system and combustion area
5. Protect against chemical or biological contamination
6. Preserve fuel and offer cold weather protection
7. Improve the quality of combustion (catalyst)
8. And so on.

The above direct actions then may or may not result in:
1. Increase in power and torque
2. Increase in fuel economy
3. Smoother running engine
4. Smoother idle
5. Reduced exhaust emissions
6. Less mechanical vibration or noise
7. And so on.

Can you see the difference? The point I am making here is that an increase in performance or mpg is typically the resultant benefit of cleaning a fuel system, engine or reducing friction. They should not always be considered as the direct aims of fuel or oil additives. The usual goal of additives is to rid the fuel system and combustion area of deposits and, thus, from these actions, restore any lost performance or MPG. Further combustion modification (catalysts) can then improve MPG further.

We often see the expectations with additives mismanaged. If a vehicle were achieving an expected and realistic 50 mpg, one would then be disappointed to discover when they purchased and used a fuel cleaner that the MPG didn’t improve if they had purchased the cleaner to improve MPG. There has to be a degradation of fuel economy in the first place. To improve MPG up and above what the engine is designed to deliver on standard pump fuel, you need to use additives designed to improve combustion and thus maximize the energy output of the base fuel, not a cleaner.

Therefore, to resolve any confusion, most fuel additive cleaners do not directly increase economy or performance. Modern detergents remove debilitating deposits and thus restore fuel system and combustion efficiency. This may or may not increase fuel economy or engine performance. It depends on what you started with. Highly quality additives with effective fuel catalyst technology can then marginally increase MPG over standard figures, depending on the quality of base fuel being used.

Symptoms can also be mechanically related. A user may inadvertently use a cleaner or additive to resolve what is, in fact a mechanical or electrical issue. This is not necessarily bad as additives can be used as a low-cost process of elimination. However, when using additives to resolve problems, it is important to understand the symptoms and, thus the probability of these symptoms being resolved through “chemical” means. Additives are not mechanics in a can.

Furthermore, a successful cleaning cycle does not automatically result in a smoother, more performant, or more economical engine. Different engine designs respond to deposits in different ways.

Many cleaners (not all) work by restoring performance and MPG. Time and time again, we see customers purchasing one-shot cleaners to improve MPG on an engine running well and achieving the expected MPG with the hope that it would magically improve fuel economy. Now, if you purchased the cleaner to maintain a clean system, then this is valid. Still, we see the expectations of many customers mismanaged when it comes to what they were expecting versus what they should reasonably expect versus what products really do and how this translates into discernible improvements to their vehicle.

The best advice we can give is for you to understand your requirements and goals concerning fuel, fuel additives, and lubricants. Don’t purchase additives on a whim or hope they may fortuitously effect some change, as this is a surefire way to disappointment. Work out what you are trying to achieve: rectify a running issue, protect the fuel system or engine, maintain a clean running system to prevent future problems, reduce wear, increase power, improve fuel economy, improve fuel quality, or many of these combined, etc. Then complete your own research or consult with a professional to match the correct products for your needs with an understanding of what the products actually do and how this translates into measurable results for you.

To summarise, there are legitimate circumstances when additives offer genuine benefits (when chosen correctly and matched to actual requirements) and other times when they become a waste of money. They become a waste of money when users misunderstand what they are actually buying versus what they are trying to achieve.

In the follow-up article, we are going to break this down further by revealing why results can be so inconsistent when using additives so that you can make an informed decision as to whether your vehicle will benefit or not from their use. We will also reveal some pitfalls, the concept of Negative versus Positive Gain, and testing protocols so that you, a consumer, mechanic or fleet operator, etc., can accurately measure your MPG improvements.

If you require any expert advice or help, please don’t hesitate to contact us, and a member of my team or I will be pleased to help.

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19 thoughts on “Do Fuel and Oil Additives Really Work?”

Richard Chebsey says:

February 13, 2020 at 4:13 pm

I am an oil heating engineer. Are there any known issues when additive is added to kerosene for use with Aga or wick burning appliances. I have a customer and I believe double the recommended doseage has been added to the fuel.

Reply
1. Andy says:
  
  February 14, 2020 at 11:18 am
  
  Unable to help without at least knowing what additive has been used?
  
  Reply
GEORGINA BROWN says:

June 6, 2019 at 11:35 am

Hi, please can you help me. I currently have a diesel X-type Jaguar and use a regular branded fuel together with AR 6900D Max each time i fill up. The car runs absolutely fine. ( The jaguar specialist who services my car told me that ‘supermarket’ fuel is inferior and is much better to use a branded fuel.) However, i am soon going to change my car to a Jaguar XE. I have been told that long term use of additives in these is not recommended and only premium grade fuel is best to use. I know that these engines come under Euro 6 emissions and AdBlu has to be added, but can i still use a regular branded fuel together with AR6900D as i do now?? rather than just a premium grade fuel, as i still have a substantial amount of AR6900 left. Any helpful advice on this would be most appreciated.

Reply
1. Andy says:
  
  June 7, 2019 at 8:34 am
  
  Your Jaguar specialist is misinformed. Premium diesel fuel contains additives such as 2-EHN (cetane improver), lubricant, detergent pack etc. AR6900-D contains the same functions to turn a standard diesel into a premium diesel but at a cheaper cost. There is absolutely no risk to your vehicle as the fuel still remains EN-590 compliant with the additive. Adblu is added to the exhaust stream to lower NOx and AR6900-D will not affect it in any way.
  
  Reply
  1. georgina brown says:
    
    June 7, 2019 at 11:26 pm
    
    Thank you very much. Your comments were very helpful.
    
    Reply
  2. Stewart Newton says:
    
    May 5, 2021 at 11:56 pm
    
    this is true of certain cars&mainly performance petrol bit believe me,vpower is no gimmick!
    my impreza sti was filled with a one off tank of tesco mommentum 99 as the shell had the fuel tanker filling the pumps&was closed off with cones so had to use tesco!the car ran ok so i used mommemtum again&again for 3 week until my car stopped boosting in 3rd gear&went into a kind of limp mode
    and wouldnt go past 80 mph in 5th gear,ran lean&my mechanic told me to use vpower again&suprise within 2 fills my impreza was spooling up nice again&popping on over run which tesco didnt as it was lean!
    supermarket fuel is inferior for sure!spend a few pence more on shell!even bp or esso etc arwent as pure as shell&ive owned modified turbos for years and fuel is important!
    i got less miles off tesco&a lean mixture!
    leave supermarkets for food&beer
    
    Reply
Thomas McHale says:

October 4, 2017 at 8:45 pm

I am thinking about buying a 2011 seat Iberia 1600 diesel the problem is that i only use it for work and back 6mile round trip the Car has done 48000 miles will I need to use a additive and how often?

Reply
1. Andy says:
  
  October 5, 2017 at 9:40 am
  
  Continual use of a detergent or combustion modifier based product such as Hybrogen Road or AR6900-D MAX.
  
  Reply
John Roseby says:

October 1, 2016 at 4:07 pm

Hi,
As a classic car owner I have been researching which fuels (petrol) contain ethanol, I now realise after a painstaking search that there isn’t any, even Vpower and BP Ultimate have 5%!! what a mess !
Have been looking at additives such as enzyme treatment ie Star Tron, then I saw your site and tech info. any advice would be helpful.
Thanks

Reply
1. Andy says:
  
  October 3, 2016 at 11:08 am
  
  Hi, the Star tron or AR6200 will resolve any issues with ethanol.
  
  Reply
Malcolm Garth says:

August 11, 2016 at 9:45 pm

Hi I hope someone can help me I have a Vauxhall zafira 1.7cdti Sri and I have a problem with rough idling it only happens every so often and it does my head in I have tried other fuel additives and I have taken it to Vauxhalls and they can’t find anything wrong with it I get my car serviced 2 times a year I have had the car for nearly 4 years now I want to try one of the other additives can you give me some advice which one would work thank you mr Garth

Reply
1. Andy says:
  
  August 18, 2016 at 9:19 am
  
  It is possible that there maybe another underlying problem that a fuel additive simply cannot fix.
  
  Reply
DAVID Curran says:

May 30, 2016 at 11:55 pm

I have been running a classic car (English ford escort 1600cc twin side draft carbs) on 97/98 octane which it runs really well on however I have recently relocated to another country where 95 octane is the highest. I completely understand the notion that you need to know what your expected result should be. In my case it’s all about performance that is to avoid detonation/pinking (knock).. But with reasonable engine protection.. What should I be considering… Thanks

Reply
1. Andy says:
  
  May 31, 2016 at 9:36 am
  
  If it is official BS 228 petrol then there is a good chance it is closer to 96 RON. An octane booster is an option but you will need to use one of the higher strength products and at full dosage to achieve a 2-3 RON increase. Also, if using continually then the oil will need changing more regularly and the spark plugs cleaned or replaced every 2-3k miles.
  
  The other option is to have the engine retuned to set the ignition timing back a little to compensate for the lower RON/MON.
  
  Reply
D kirby says:

January 24, 2016 at 8:32 pm

I have a 1.5 Renault scenic diesel 120000 miles runs ok .would any of your products improve mpg

Reply
1. Andy says:
  
  January 25, 2016 at 10:00 am
  
  Hi, I would try AR9100 in with the oil and test both AR6200 and AR6800 to see which gives the you the best results. UPDATE: I would recommend the new AR6900-D Max.
  
  Reply
Mark says:

August 31, 2015 at 12:36 pm

i dont know if they work yet or not, just ordered this product, plan to use it in the oil (currently i am using 5W20 synthetic w/ 1pt Lucas), differential (front and rear), transfercase, and power steering, ~ i feel alittle insecure about putting it in the transmission. i work as a traveling home healthcare worker in a rural community, I drive 80-120+ miles/day in Mid-Ohio area, so i have a 4×4 (because of Snow), ’99 Jimmy with 270xxx miles, i write my mileage down at every fillup and it varies mpg 18.5 – 22 (average over time would be like 20-21) hoping this helps ALOT, as the companies i work for have stopped paying mileage …

Reply
Sue Black says:

September 1, 2014 at 11:55 am

Hi I wonder if you can recommend which product may help with my Renault Grand Scenic 2litre Diesel. The Engine Hazard Warning re Anti Pollution system light came on and I took it to a garage who charged me £50 for removing the warning and mentioning something to do with Turbo system and clogging? Advised me to go on a long run as local driving may have caused a build up. I had at that time recently driven to London and back! It has since come on again returning from a 100 mile trip to Wales and back. I have been googling and saw your site and wondered if your product may be the answer to my problem?? Your advice would be appreciated Kind regards Sue 07973187292

Reply
1. Andy Archer says:
  
  September 2, 2014 at 8:15 am
  
  Hi Sue,
  
  It is difficult to establish the cause base on the information provided. Did they advise of the error code the warning light produced?
  
  Either way I would first try AR6400-D in a full tank of fuel as a process of elimination.
  
  Regards
  
  Reply

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