July 7, 2015

Is All Petrol & Diesel The Same?

PistonheadsIt’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.

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 !

    • I drive all over Europe,using the cheapest fuel that I can find. My Movano dropped a valve with just under 400000 miles on the clock, my SEAT Inca is still going after 325000. Regular servicing is more important than expensive fuel.

      • That tends to confirm another my belief that long journeys and regular servicing are the best way to keep a car healthy, especially with today’s long-life service regimes which can see diesels untouched for two years or even more at a stretch, when their owners don’t do many miles.

        For taxis, maybe the benefit of better fuel is in low-speed running, where wear and tear is greater and better additives help keep the engine cleaner?

  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 (SimpleMotoring.co.uk)

      • 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.

  23. Jim Robson says:

    I have owned an Audi A3 2.0 litre TDi S-Line for the last 4 and a half years, and only ever filled with TESCO diesel. The car has been serviced regularly, and the exhaust gases tested for the MOT Test every year since 2013. It has just passed 70Kmiles and until recently ran around town and long distance giving 50plus MPG.
    However, on a recent trip the engine suddenly lost power and warning signs for “Emgine Management fault” showed on the driver information system. I then drove the car some 30 miles to my regular service centre, who advised that the EGR system which re-circulates hot exhust gases through the Turbo into the engine (in order to maximise fuel economy, and minimise pollution. The cost of the repairs was in the order of £800, including VAT, and took 5 man/hours in the workshop to complete. A box of new Audi Parts was installed, and the old parts were show to be full of black carbon soot deposits.
    I have been advised to use only Sheel, BP, ESSO, or Total diesel fuel in future, and the engine will burn cleaner, and without leaving sooty deposits in the Exhaust Gas Recycling valve unit.

    My previous car was an Audi A4 1.9 litre TDi and part from timing belt changes and regular servicing, it gave me 13 years and 270 Kmiles of trouble free motoring, using Supermarket diesel.

    Does anybody else have a similar experience?

    • Mike Smith says:

      The problem you have experienced is not the brand of fuel, it is the diesel particulate filter not being cleared of soot.
      This will happen again unless you look for the DPF regeneration instructions for your car. Diesel cars with the dpf are no good for city/town driving without frequent fast road journeys. There are many articles online explaining.
      I have just changed my volvo d5 for a petrol BMW after paying £850 to clean the filter and EGR.

  24. andrew hurden says:

    I’ve worked at Milford Haven Oil Refinery for twenty years. Different fuel additive pack are used in supermarket tankers, I can assure you of that. Supermarket fuel is ok for some vehicles but not all. Its down to Engine management architecture and the engines ability to adapt to slight changes in Octane etc. One can add something like Millers fuel additive which is brilliant stuff.

  25. andrew hurden says:

    The oil industry is struggling to keep up with the latest advances in engine technology. Manufacturers are producing ever increasingly frugal, lean burn engines with advanced turbo technology, in line with European emission legislation.
    If one has successfully run a vehicle on Supermarket fuel without any problem that’s fine. My personal advice to anyone running the new breed of highly tuned turbo petrol or diesel engines is play it safe and avoid supermarket fuel. The odd tankful won’t hurt.

  26. dave pearson says:

    just had first experience of contaminated fuel in 35 years of driving, put £60 deisel in my ford mondeo 2010 at asda on portrack lane STOCKTON-ON-TEES, after a few miles spluttering lack of power and no speed this was Sunday 29-03-2015 around teatime, so tried car again Monday same problem, so Tue I put car on diagnostic machine nothing wrong with car at all, so after returning to asda and explaining problem, they took my details and said someone would get in touch wit me, next day someone phoned me and said an investigation would take place, so I arranged with my brothers help to drain £60 worth of fuel from my car, when we got it all out, it was thick and very cloudy and discoloured, it looked and felt in my fingers just like cloudy cooking oil, it never cleared and is still thick cloudy oily mush, I then removed fuel filter it was caked and choked in sludgey oil like used chip fat, I put a new fuel filter in, bought a 5 litre can of deisel from BP garage on Durham Rd STOCKTON-ON-TEES, before I put this in my car, I poured a sample into a glass to inspect, CRYSTAL CLEAR, put it in my car, lovely car a dream driver again, I await asda test, but Ive got sample for trading standards, and after 35ish years of driving never again will I use ASDA fuel, IM just glad I was able to save costs and drain car myself.

  27. I drive a 2003 Subaru Impreza WRX and have done 165 000 miles in it. I have only used Tesco Momentum 99, Shell V-Power and on a couple of occasions BP Ultimate. BP Ultimate is far too expensive and also seems less powerful than the other two. For the past 5 or 6 years I’ve been filling up with Tesco Momentum 99 more frequently than Shell V-Power as it is not only less expensive but seems to deliver more power above 60mph. Both deliver about 27.5 mpg and as the high mileage suggests I’ve had no engine problems using Tesco Momentum 99. I think you should experiment with different petrol brands and use the one that you think best suits your own particular car.

  28. Spiro Ozer says:

    I run a ten-year-old diesel Nissan X-Trail. Twice in the last year I have had trouble with it misfiring at speed; both times the problem started just after filling up at a Tesco station. On both occasions, as soon as I refilled with new diesel, the problem disappeared.

    Now this may be coincidence – and I have many times filled up with Tesco diesel and *not* had a problem. However, I don’t think it is a coincidence. I think that Tesco stations occasionally buy in bad batches of fuel that happen to be going cheap. Don’t ask me to explain “bad”, or why different batches made by different refineries to the same standard can behave differently in my engine. I only know what I have observed, and I’m never going to buy Tesco diesel again.

  29. My high mileage 58 plate Corsa diesel was stuttering & stammering for a couple of months so someone who knows a bit advised me to use Shell diesel rather than Asda which I had previously used. After changing to Shell normal diesel I didn’t notice any significant difference so gave Shell V-power a try. It became ten times worse using V-power. I swapped back to normal Shell diesel again and it’s back to it’s normal level of stuttering again. I thought if anything the V-power would help. Has anyone any ideas as I’m stumped?

  30. I drive a Vauxhall Insignia cdti auto with a mixture of town and motorway driving and with Tesco diesel I can achieve only 40-42mpg but using Shell (which is more often) I achieve 50mpg easy and I must say I have quite a heavy right foot. So She’ll is best for me.

  31. Mofazul Ullah says:

    I was told by the fuel card issuing company two main players BP and Shell, BP high grade for motorway driving and Shell VPower for local.

    Good for your pocket and your engine, it costs a little more but cheaper in the long run with no repair bills.

  32. Toyota diesel D4D engine management light illuminating and engine going into ‘safe mode’ every 40 miles or so at 100,000 miles. Garage suggested new/cleaned injectors at price of £750>£800. Changed from supermarket basic to Texaco basic…result no recurrence in last 2500 miles. No brainer really as far as I am concerned.

  33. Michael Hollinshead says:

    Very interesting! Just for the record: Diesel Peugeot 407SW Auto HDi – Problems with power loss from time to time, no acceleration. Garage said it was possibly ASDA diesel doing it. A can of fuel additive in the tank and change to Shell! I ran the car down to 25miles left (!) and filled up (car holds 67L) with Shell V Diesel.
    Result, the car started to go like it never did before, so lightened right foot. This resulted in an extra 47 miles to a tank full! I always run on Shell V now. Always at least 40mpg better than of old.
    I am getting a second hand Volvo D5 sport next week. I intend to run that on Shell V too.
    P.S> Err….Shell? Any chance of a discount? (Got to be cheeky!)

  34. Paul Pickering says:

    Most of the feedback about fuels mentioned here major on main brands v supermarket , but what about the minor ones such as Murco, Gulf, Q8 Etc. how do they fare? Observations of their quality and performance would also be relevant to this debate.

  35. harry draper says:

    i have been a taxi driver for 30 years,have usually gone for cheapest fuel and have taken cars to around 300000 miles with no engine problemsi would have put more miles on them but our council has an 8 year age limit for cars so friends and family end up with my old cars!

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