March 29, 2015

Is All Petrol & Diesel The Same?

Is all petrol and diesel the same, wherever you buy it from?

It’s a common question that often gives rise to heated debate between people who swear that their car runs better on fuel from XYZ Company and those who say that it’s all the same and they just buy the cheapest.

The problem is that most people don’t know how the fuel business works, and the truth is a little harder to find.

The Easy Bit – Premium Fuels (Shell V-Power, BP Ultimate, etc.)

Let’s start with the easy bit. Premium fuels, such as Shell V-Power Nitro+ and BP Ultimate are not the same as regular petrol or diesel fuels, although you can mix them freely with standard fuels without problems. Petrol like this is known as ‘super unleaded’ — confusingly, what is labelled as ‘premium unleaded’ on forecourt pumps (e.g. Shell Fuelsave) is actually standard petrol.

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These ‘super unleaded’ premium fuels cost several pence per litre more, have a different, more sophisticated package of additives for cleaning and lubrication, and have a higher octane rating (petrol) or cetane rating (diesel).

Octane and cetane ratings describe the way a fuel burns inside an engine. Broadly speaking, a higher rating means a fuel will burn more efficiently and effectively inside your engine. This may improve performance and/or economy slightly – although not all drivers will see a noticeable difference.

Some supermarkets also offer their own super unleaded — notably Tesco, which offers Tesco Momentum 99 octane. This is usually cheaper than Shell V-Power or BP Ultimate but opinions vary as to whether it provides the same cleaning benefits and mpg improvements that are claimed for the top two fuels.

Tesco Momentum 99 super unleaded reportedly contains more ethanol than super unleaded fuels like BP Ultimate, which some people claim provides an octane boost but may not provide the same efficiency gains as the more expensive branded fuels. Like everything to do with fuel, people have different opinions, and the facts are hard to find.

Standard Unleaded and Diesel Fuels

The big debate is over whether the petrol and diesel sold by supermarkets is the same quality as that sold by branded fuel companies like Shell, BP, Esso and Total.

Let’s start with some known facts:

All fuels sold in the UK conform to the relevant British Standards. This means that they should all work in roughly the same way and you can mix them freely in your car’s fuel tank.

The standard petrol and diesel that’s sold on garage forecourts is mixture of two things:

  • ‘Base’ fuel
  • An additive package

The base fuel is the same for all companies – in fact, it usually comes from the same tanks at the local fuel refinery/distribution centre. What varies is the additives package that goes into the fuel. These additives packages are secret recipes of extra ingredients that help keep the engine clean and improve lubrication inside the engine cylinders.

Each fuel company has its own additives packages and these are different. So it is possible (but not common) for some drivers to feel that their car responds better to the additives used by one fuel manufacturer over those of another.

What About Supermarket Fuels?

There are all sorts of stories that go round about supermarket fuels, but the fact is that supermarket fuel tanker lorries are often seen filling up from the same tanks as branded fuel lorries (e.g. Shell, BP) – so the chances are that most of the time, the fuel they sell is the same, although again, it may have different additives packages.

However, one common story about supermarket fuel is that some supermarkets don’t have a regular fuel supplier. Instead, they buy odd lots of fuel from wherever it’s cheapest. This could (if it happened) lead to supermarket fuel having a more variable set of additives than branded fuels.

Not many people really know the truth about this business, and they are not the kind of people who will reveal all on the internet, so we will have to keep guessing as to whether there is any meaningful difference between supermarket fuels and branded fuels.


  1. Richard says:

    If you take a look at a list of refineries you’ll see that there really aren’t that many. So what happens is that standard grade fuels are pumped into each company’s tankers and the quality is the same. The difference comes in the additives that each company adds to its tankers. These might affect performance, so if you feel your car drives better on one type of fuel, keep using it. However, the fuel from different refineries may differ enough to blur any distinction. There are other variables too, but that would take several paragraphs to go into. As for supermarket fuel, it should all be of a minimum quality standard. So how come it is cheaper? There are three possible answers – a more flexible distribution network, fewer (or poorer) additives in the fuel, and thirdly, the fact that the big supermarkets are prepared to discount – they sell lots of things, not just petrol and chocolate bars, so they can afford to make a slight loss in order to attract customers into the stores.

    • @Richard

      Thanks for such a detailed comment, the point about the supermarkets selling fuel at a loss is a good one and something that seems likely to be true.


  2. Lee Harding says:

    I drove for many years in the London area and never had any rhinitis or breathing problems. Looking back it seems that my problems started once ‘cleaner engine’ additives were introduced. (I know I’m going back a bit). Does anyone know of any research into the short & long term effects of these ‘cleaners’ on health? Also, do other countries use a different mix of base fuels and additives?

  3. John White says:

    I have a Nissan Pathfinder its just 12 months and have had several instances of it going into “safe Mode” Nissan dealer has checked it out and could not find a problem???? They also asked what fuel I used and when I said Tesco they said that is the problem “It is a lower grade fuel to Shell or BP” So this is what I have used and Nissan tech Centre have issued an instreuction to their garage outlets advising them to say Dont use suppermaket fuels?

  4. Mohammed sajed says:

    I’m a taxi driver , our biggest expenditure is fuel ,
    Which we use plenty off , from past experience
    Shell & BP petrol & diesel is 100% better purely
    Because of the additives used , supermarket fuel
    Is cheap & nasty , our vehicles became sluggish
    & performed poorly with supermarket fuel , we now use shell V power , it’s a lot better & cars do more miles per gallon , well worth the extra cost !

  5. Hi I’m happy to put the mileage difference to the test. I drive the same mileage every week on the same roads in a 2.7 Porsche Boxter. So today I will fill up from empty with Tesco premium unleaded and record the mileage on here. When it runs out I will repeat the process but with BP Ultimate…..results in a couple of weeks. : )

    • Hi Peter,

      It should be an interesting comparison, look forward to seeing the results!

      Cheers, Roland (

      • Okay just so you know I haven’t forgotten; I got 270 miles from Tesco premium unleaded. Just filled with BP Ultimate, results in a week. (This is mileage measurement only not performance).

      • I got the same miles from the BP roughly 270.

  6. Dear Friends,

    Talk about additives useful. Thanks.

    My particular problem, specific to metallic additives. Have a VW Polo. VW state clearly that metallic additives are HARMFULto their engines.

    From reading around it seems clear that Shell & Bp (probably true also of Esso top brands)certainly do not have metallic additives. Ie the top brands, more expensive, are metallic additives free.

    Will move to their more expensive ranges for what you say, Mohammed about better mileage and cheaper in the long run is pretty persuasive.

  7. simon collins says:

    I am launching this new product very shortly, which given the above discussion, i thought you may be interested in.

    Its called the peoples fuel card and will enable drivers to pay with the card at the pumps and receive between 4-15p off the advertised price. There is no catch and you get to pay bi monthly or monthly, much like a mobile phone bill. If you are strapped for cash, you can still fill up and at a cheaper rate.

    i need 10,000 people for the company i am dealing with to do the deal.

  8. Mr Kevin Mohammed says:

    Hi there, ive had my Fiesta st for just under a year. And since day one, ive used BP ultimate. About six weeks ago, an Asda station opened on my doorstep. An as it was cheaper, I started to use that. But since I started using it my car has been very sluggish, and rough to drive. So from now on, im going back to the BP ultimate unleaded.

  9. I’m a Taxi driver and like most taxi drivers I stay well away from supermarket fuels! For two simple reasons – economy and for the health of my engine!

    Some engines take cheaper fuels better than others but Diesel engines particularly should stay away from supermarket fuels – they dont do EGR valves, injectors and DPFs any favours resulting in expensive repair bills. Vauxhall CDTIs and the PSA engines found in ford,Volvo,peugeot,and Citreons dont like supermarket fuels either resulting in problems mentioned above

    Only my opinion but shell is the best

  10. lyn cavanagh says:

    My injection seals have gone on my M Class Mercedes 2004 plate. SOne one non mechanical has said it’s because I’ve used tescos diesel?? could this be true or is it something that’s just said? now got a car I cannot use as cannot afford repairs?

  11. No that will be age a mileage i had a 2004 vito and had to have the seals done, ive gota new vw van and been using tesco fuel from day one about a month now and im noticeing the fuel going to quick even with no weight, think im going to convert to bp or shell when the tesco diesel is empty

  12. I avoid Supermarket fuel as advised by Honest John Daily Telegrapgh IME it is inferior to both Shell & Esso.IMO Shell V power is a waste of money no improvement for mpg on my KIA CEED 1.6 CRDI auto for me best diesel is Esso Standard. puts a tiger in your tank ha.

  13. Mario Lazlo says:

    I have used Tesco diesel ONLY in my Toyota Verso when bought it brand new in 2010, done 207000 miles and not a single problem…So all you talking rubbish here,that supermarket fuel is bad.
    And earlier I have used Morrison diesel for 3 years on Peugeot 308 and 157000 miles done without a single problem on engine.

  14. I bought my first diesel car 2006 Alfa Romeo 150 2.4JTDm. Standard 200BHP. With full Meridien Milano service history. Mileage at the time was 101,234 miles.I was running my car on shell diesel and the car was rough at start up so I tried the v max diesel and the car loved it.I had the car Terra cleaned by Monster Truck Milton Keynes and the management light came on.
    The customer service was great but my car broke down days later and won’t start. Computer said dpf filter blocked. The car was taken to MK Motors in Birmingham who performed a remap and the car was transformed. Better miles per gallon around town and 43mpg on long motorways. With my average miles around 37mpg with my driving style.I have now fitted a oil catch tank. I love my car and it’s been reliable so far.

  15. Tesco delivery vans and lorrys use tesco fuel infact I work for tesco dot com and drive there vans they have done 80000 miles (80 vans) in just under 2 years and most common breakdowns is gearbox problems and over filling of oil

  16. Stay away from supermarket fuel! (especially Sainsburys)

    When I got my BMW 520d 2 year back (3 years old then), I started with Sainsbury’s city diesel. After 2 weeks my car started show up error messages. Took it to a mechanic, he charged £70 to tell me that your EGR Solenoid is choking and it would take another £350 to replace that.

    I came back and read online to check. Someone on pistonheads suggested to fillup with Shell V Power and go on a long drive. I did that and the error message disappeared. 2 years and 50,000 miles later I still use Shell V power, never had any issue at all, even through I mostly drive to work in London and very few long drives.

  17. Ted Colloins says:

    We have a Ducatto van camper which we use for weekends away some 20 times a year marshaling on motor rallies and we always start with a full tank, and fill it up when we get home, and check the mileage. We have done this for several years, with this and two previous campers. I get 33 mpg on esso diesel, and I do occasionally try supermarket fuel, and find I get 27 on Morrisons fuel, and 29 on Tesco. We also have a diesel Clio, and checked full to full, I get 51 round town on esso, and 47 on the supermarket stuff. Need I say more.

  18. I personally only use shell fuels. I think alot of the time when you read reviews or forums they only ever talk about what mpg or performance gains they got on that one tank of said fuel. I think they miss the point alot of the time in that using a quality fuel helps look after and keep clean the fueling system and engine of your car. Its like a long term protection.

  19. my vw passat mk 5 1.9 se tdi is 11 years old bought new it has never had super market fuel ever in the 11 years i have never had problems with the fuel system apart from the turbo charger needed cleaning about a year ago successful result the car has 84000 miles on the clock it returns 54 mpg in normal use .it has towed an advantie 534 caravan all over europe and apart from a starter motor and new battery last year the cars has been perfect

  20. Julie Timmins says:

    What do all you diesel Audi A2 drivers fill up with?

    • A “Diesel Audi A2″ is very special! Obviously you have to treat this wild beast similar to a Jag or a Bentley.

      I recommend nothing but ,Shell V Power Super Nitro plus plus Diesel, for your A2.


  21. Ted Colloins says:

    I think we are losing the plot here ! The life of any engine is dependent on many things, any engine that is serviced correctly, and has the filters changed regularly, will give good service regardless of where the fuel comes from. The point of this forum is to expose the poor running performance of supermarket fuels, not to suggest which cars run best on what fuel. Its a fact that, as a country, we could save some 5% or more of our total fuel import, with all the tree huggers jumping for joy, if the government got its finger out and made an ignition level specification to which all fuels should comply. But that would mean there was less sold, so less tax income, so ‘fraid its the status quo that will rule. Rock on fellas !!

  22. Well,this is my 3months experiment summary.driving daily 60 miles round trip Ford mondeo Tdci 130Bhp changing fuel after fuel meter drops to bellow reserve level every time taking 20 ltrs in Stafford town,conclusion? Shell Nitro 55.5mpg,Gulf cheap diesel 54.7mpg,Esso Premium 54.7mpg,cheapest Asda 55.2mpg sure and absolutely unbelievable,best fuel for money.Well,it is not always possible but thorough testing I was trying hard to keeping revs while changing gears bellow 2000 and drive not faster than 60mph between Halesowen and Stafford mainly motorway ride,somebody will argue but if you want to say that I’m a lair than be careful. This is serious testing not just talking about what other people says or what you have heard of some guy.

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