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Supermarket petrol??! - Foggy
I posted a question earlier and mentioned the fact that I put supermarket petrol in my car (a Rover 620 Ti which I've run for four years, has 78,000 on the clock and still no smoke!. I'm about to change and buy a '96 BMW 728i with 30,000 miles on the engine.

Shell Optimax seems very popular on the web (but expensive on only one garage in Cardiff) - so my question is this. Should I stick to one brand of petrol? BP? Shell? Texaco? Will supermarket petrol really hurt my car? Unleaded or Superunleaded?

I'd love to hear evryones views, but especially those who work in the petrochemical industry or in vehicle research!!


Tags: technical issues high mileage misfuelling new cars petrol or diesel?

Supermarket petrol??! - Ian (Cape Town)
Foggy, congrats on your new motor!
I suggest you do a search using "supermarket" "tesco" or similar as serach arguments ... you'll be surprised what comes up! (Most of it rather negative!)
Supermarket petrol??! - Honestjohn
Supermarket petrol??! - Cyd
Most engines that are fitted to cars which are sold around the world are tested to run on "the dregs from some sunken oil tanker" because in some parts of the world that's all you can get.

Any given car may well run "better" on one particular brand, but fitting supermarket petrol won't actually harm the engine. My Rover Vitesse Sport (same engine as 620ti mentioned above) hasn't missed a beat in 32000 miles run on petrol from the same Tesco in Coventry (with the exception of a few tanks) and it passed 117k today. I tried Optimax (on the road) - it doesn't seem to make any noticeable difference to this engine, but I will try it again next time I'm on the track.
Supermarket petrol??! - Foggy
What would you suggest? I've local BP, Esso, Texaco, Elf garages, but only one Shell a fair drive away [ :-( ] - any preference? Should I use Super Unleaded or normal Unleaded? what differences will I expect?

PS Can't sleep..wantcarnow.Nownownownownownow. Please Mr RAC tell me all is good. please. pleaspleasepleaseplease....

Supermarket petrol??! - svpworld
I guess at the end of the day, it depends on whether supermarket petrol is really inferior to other brands. We are talking just a few pence per litre, perhaps a pint of beer on a full fill up... if there is evidence that branded fuels are better for the car than "supermarket" stuff, then I believe its worth avoiding the latter. I dont think that supermarket fuels will harm a car, else they would never sell the stuff and be under some pretty serious law suites... however its probably like drinking tap water as opposed to spring water. I always would use supermarket fuels in my cars, but now having joined this group I will stick to branded fuels and if poss, optimax. It would be very interesting to do some specific testing on different brand fuels to see if there is any noticeable difference in a cars performance, running and smoothness, economy etc. Although all fuels go bang at the end of the day in the cylinders, the injectors, fuel pumps, pipes and filters will carry the stuff prior to ignition and their reliability will depend on its quality. further more, once ignition has taken place, deposits, exhaust gases and contaminants in the gases will depend on the fuel quality and will also contribute to catalytic life, plug life, cylinder bore deposits, piston wear, valve wear, etc.
We all take great care in choosing a good engine oil to preserve the life of the motor, though I still think that more frequent changes (filter and oil) using a standard oil are better than prolonged usage of a high grade synthetic. Infact has anyone noticed a big difference when replacing their oil with say Mobil 1? (apart from the garage bill!).


SVPworld (incorporating PSRworld)
Supermarket petrol??! - smokie
< >

You may have read here recently that Kwikfit are doing a mobil 1 oil and filter change for £34 all in.
Supermarket petrol??! - Dizzy {P}
It is repeatedly claimed by two or three people on this forum that petrol from supermarkets is inferior to supplies from other sources.

Could one of you please reveal the scientific test results that support this claim. Thanks.
Supermarket petrol??! - Toad, of Toad Hall.
In a huge thread below nobody provided a definative answer.


Parp, Parp!
Note: All Toad posts come with an implied smiley.
Supermarket petrol??! - Flat in Fifth
Plus hardly anyone came up with a comment on my ref to Ford saying that fuel quality could be more important than oil quality.
Supermarket petrol??! - Toad, of Toad Hall.
Plus hardly anyone came up with a comment on my ref
to Ford saying that fuel quality could be more important than
oil quality.

Without a definition of what makes a fuel good quality it wasn't that useful...

Parp, Parp!
Note: All Toad posts come with an implied smiley.
Supermarket petrol??! - Flat in Fifth
Just spoken to Ford and more or less had a blank from their PR chap. He didn't know of any information which was already in the public domain, and if not then clearly they are not willing to release to the great unwashed here. Nevertheless he has promised to forward on questions to the relevant engineers so.......

Come on then chaps, pose the questions here and I'll pass them on in a day or so. (we didn't manage to nail Stephen Byers so maybe this time ;-)

Secondly his best suggestion was to get Andrew English, the journalist writing the DT article, to follow it up again.

Andrew if you visit this site, what about it?
HJ could you give Andrew E a dig if not?
Supermarket petrol??! - Dizzy {P}
In the previous thread on this question, which I've just read for the first time, you reported Ford as saying: "...the quality of the oil you use is less important than that of the fuel, especially when it comes to diesel engines". I wonder if the Ford PR man could put more detail on this for us?

I realise that high sulphur petrol can be damaging to some engines (ref: the BMW Nikasil issue) and that low sulphur diesel can be damaging to older engines unless it has a suitable compensating additive. Is this what Ford was referring to? Or are there other things to be wary of?

Perhaps Ford could also tell us whether or not there is a distinct quality demarcation between supermarkets and other retailers' fuels. I would love to see supermarket fuels shown as being inferior - they are getting far too dominant and greedy - but I've seen nothing yet to substantiate this.

Supermarket petrol??! - Flat in Fifth
Hi Dizzy,

The PR chap was not prepared to commit himself at all. The offer to pass questions on came before he thought of the option of getting Andrew English of the DT to follow up on the basis that Andrew raised some reader questions in the piece. Actually that is the better solution if HJ/AE reckon there is mileage in it.

Now I can fully accept that if Ford have unpublished research results available then they are not going to release it to some gonk phoning up out of the blue. That is fair enough and it is no more than I would do if asked about some of my research projects. All I asked about was the possibility of an off the record discussion or pointing in the direction of any information which is already in the public domain. However I know when I'm getting blanked and fobbed off and told the PR guy so direct.

If you read the original article you will find the quote from an unnamed engineer as in the previous thread.

The article was rather interesting and the link is here >>

In case the link dsoen't work it was called Natural Born Car Killers filed 10 August.

Unless someone can suggest a better tack I'm going to try the following. I'm a Ford customer due to take delivery of a new Mondeo Estate TDCi (totally true as it happens) and I would like more information on the detail behind the comment. Particularly in that one of their engineers has made a comment, which presumably the press office was perfectly happy to be attributable to Ford. Or something in that vein.

Like you I was surprised by the comment considering what we all do with regular oil changes etc. The answer or lack of one will be interesting. Though I will accept that if the answer arrives in the form of a private communication from Ford then I will respect that this should not be published.

Of course that would not stop me publishing the lack of an answer would it? Hur Hur.

As for proving supermarket fuel one way or the other I have no agenda there, just would like to know.

Cheers, keep you all posted.

Supermarket petrol??! - jmc
The "fuel pump" on my 8 week old 3,000 mile Focus TDCi has failed although I wasn't told which particular component was the culprit. However the job, under warranty of course, seemed quite big as I saw the engine in what seemed to be a pretty stripped down state. Yes I had used mainly Sainsbury City Diesel but in case there is a connection will revert to Shell in future.
Supermarket petrol??! - BrianW
See my post below.
I would be surprised if the pump failure was connected to the fuel used, especially at that mileage, more like a manufacturing/assembly fault.
Supermarket petrol??! - Flat in Fifth
Letter gone off, cc Andrew English & HJ.
29 Aug
Reply received from Ford - Flat in Fifth
As the title suggests a reply has been received, albeit a fairly non-committal one, probably as might be expected.

In a small nutshell basically Ford appear to be saying that they recommend in the handbook that BS EN 228 (petrol) and BS EN 590 (diesel) fuels should be used. That's about it.

they also comment that most diesel fuel on sale in UK meets this standard. (my emphasis)

Therefore Ford appears to be admitting that some fuel does not meet the standard, but which ones ??? For the ones which do meet it; as we all know all animals are equal but some are more equal than others.

They go on to say that where the standards in certain markets generally deviates then the effect of this is reflected in the service and maintenance regime.

Of course this does nothing to answer my question for clarification of their comment "if you fill up with worst case fuel in Britain...."

However I have printed out the .pdf file they've sent and will peruse the contents. Anything interesting I'll report further. The bibliography at the back certainly contains some interesting looking leads to follow.

Supermarket petrol??! - chris taylor
regarding the mobil one thing - i once had a renault turbo with 80k on the clock and decided to use mobil one- talk about rattle!.
I agree -best to stick to standard oil and change every 6k especially on higher milege engines. I sold that car at 130k
still on the original engine/turbo and it was driven fairly hard, mind you it had a fsh with regular oil changes.

Does the supermarket thing apply to diesels or is it a myth that they will run on anything?
Supermarket petrol??! - BrianW
"Does the supermarket thing apply to diesels or is it a myth that they will run on anything?"

All I can say is that I ran our Pug 309 almost exclusively on neat supermarket diesel for 90,000 miles, finishing at 120k with no noticeable drop in performance and it never missed a beat.

Ditto petrol for 80k on a 250cc motorcycle.
Supermarket petrol??! - Honestjohn
Heavier diesel naturally has a higher cetane rate than light low sulphur diesel so an old generation diesel will run better on it and also smoke more.

Supermarket petrol??! - matt35 {P}
About a year ago I asked HJ if I should use Optimax in a new X Type - his reply was roughly 'why spend a lot of money on a car and use cheap petrol'.
You are getting quite a special motor which is hardly run in yet?
Whether Optimax is better for your engine or not is probably subjective - there is a long discussion on the subject on this BB.
I drive past a lot of filling stations to find Optimax about 8 miles from my home and notice the difference in performance and in what the trip computer says about mpg if I fill up with supermarket fuel in emergency.
Personally, I would be surprised if BP and Texaco did not have a very similar product to Optimax - maybe HJ could comment on this if it is not to producer sensitive?
Regards - and enjoy your new car!
Supermarket petrol??! - Foggy
One quick point. Let's say Optimax is 80p/litre and Supermarket Slurry is 74p/litre. If my old Rover did 30mpg on the Supermarket stuff, then it would have to do 32.4 mpg on the Optimax before I was any financially better off. Then I have to take into consideration the time difference to get to the Shell garage (about 30 mins rund trip) and 12 miles worth of petrol (possibly £1.60 worth). I'm sceptical as to whether it's worth it in my case. If I lived next to a Shell garage then maybe

PS Had the RAC inspection today (amazing what they can tell you!!) - someone has keyed it down both sides in the past and the panels have been resprayed but there's ben no impact damage. Oh - and the oil was a little too full and the power steering fluid a little too low. But 'nought else wrong!! Just waiting for the money to clear and she's mine!!

Supermarket petrol??! - Cymro Arall
Foggy: where's the Shell garage in Cardiff? I too have to search for Optimax. It seems to give about 9% improvement in mpg for my car (though the price is about 8% greater, so the economics are more or less neutral).

Supermarket petrol??! - <0.One%
Foggy: where's the Shell garage in Cardiff? >>

Foggy an others who would like to find their nearest depot:

Click on


Go to third question from end of list:
Is Shell Optimax available at all Shell service stations?"

This will take you to:

"Where to fill up with Shell Optimax
Finding your nearest site
Look out for the Optimax banners and signage on our forecourts or try our easy to use online search facility to locate the nearest site to your home or work place.
Alternatively you can call our Customer Service Centre on freephone 0800 731 8888 or send an email."

Then use the search faciltiy to bring up maps of nearest Optimax stations.

Supermarket petrol??! - Steve S
I'm pleased with the effects of supermarket petrol - it keeps the prices reasonable at the nearest Shell/BP/Esso garages!
Supermarket petrol??! - svpworld
There's one next to the Mercedes dealership off the Pentwyn exit on the A48. Head out towards North Pentwyn (signposted to the Holiday Inn hotel) - 2nd exit on r'about if you are heading in a Newport Direction along the A48. Shell station is just past the dealership and before a speed camera on the next bend!


SVPworld (incorporating PSRworld)
Supermarket petrol??! - <0.One%
Foggy's first post said:
I'd love to hear evryones views, but especially those who work
in the petrochemical industry or in vehicle research!!

If you go to:


you will find that they invite you to "ask an expert:

Dr Cathryn Hickey is one of the UK's leading experts on fuel quality and fuels development. She works closely with motor manufacturers and motoring organisations to ensure that our fuels meet the demanding needs of our customers, and deliver optimum performance for today's driving conditions. You can email Cathryn or see what questions have been asked so far."

How about asking her and telling us know what she says?
Supermarket petrol??! - Andy
My car handbook states use diesel to EN 590 specification. I looked on the diesel pump at Safeways last night ( to use my 20p a litre discount) and it was labelled EN 590. What more can be said.
Supermarket petrol??! - PhilW
How do you get 20p a litre discount?
Supermarket petrol??! - Pat L
It's really weird! I tried Optimax again last but one fill up due to posts here (despite disappointing results last time I tried it back in 2001), and found that the car (Merc 190 1.8E) ran noticeably poorer, but ran better on the next fill up at the supermarket! Why is that? Did the Optimax clean out the pipes etc?

Supermarket petrol??! - Andy
Hi Phil,

If you spend £150 in the store Safeway give you a voucher for 20p a litre off their fuel. The offer starts at 2p for £25 spet up to the maximum of 20p. We usually do aa big shpo once a month to take advantage, fill the car up and it lasts 2-3 weeks.



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