Which Diesel Fuel - Jagman
I currently run a 98 Audi A4 2.5 Diesel Quattro Avant (93K miles)in which the engine has been vibrating slightly more at idle, I think the injectors may be slightly gummed & a shot of injector cleaner will be used at the next fill-up.
My question is which is the best Diesel to prevent gumming.
I have done 10k in the car & have filled up with Esso 99.9% of the time. I have also used Esso in my previous diesels without any known problems.
Which Diesel Fuel - oldtoffee
Hi Jagman,

I use Millers Diesel Clean Plus at most fill ups and my Passat TDi runs well. Until recently I've been using Sainsburys City Diesel (4p a litre off plus Nectar points). But I've been following the Shell Optimax thread here in the BR and HJ's advice and I've now filled up 4 times with Shell Diesel and I've noticed that the car is running smoother through the rev range particularly under acceleration. It's a definite improvement not just imagined which is a bit of a downer because if I stick with it which I'm inclined to do, I'll pay more per litre than I have been paying. Suppose you can't have your cake .....
Which Diesel Fuel - volvod5_dude
I fill up with Safeways diesel once a month and take advantage of their 20p/litre discount. Then I use ESSO in between, there are no Shell garages near. I also add a bottle of Wynns diesel injector cleaner which is also a lubricant every 3 months or so (about a fiver). Seems to keep things running sweet.

Which Diesel Fuel - Jagman

Thanks for info, I have heard good things about Shell diesel before & as there is a local Shell garage I may switch for a while & see what difference it makes.
Which Diesel Fuel - mare
I notice a 3-5 mpg gain after a fill up of my Octavia TDI at Shell. Thought that i was imagining it, but there is a distinct pattern forming. Much more efficent than Esso or Texaco.
Which Diesel Fuel - Vansboy
Don't forget to sign up for the Shell BonusPoints card, worth about 1p/ltr discount, plus other extras, depending how much fuel you buy.

Which Diesel Fuel - Jagman
I have now filled up twice using Shell diesel & the Audi has had a shot of injector cleaner, I can report better starting from both hot & cold & a very slight increase in economy. I am putting both these points down to the injector cleaner rather than the fuel for now. I will post again after another couple of fill-ups without the addative.
Which Diesel Fuel - daryld
It's tue...Shell is best:

Which Diesel Fuel - MichaelR
I always fill my Xantia up with Sainsburys City Diesel becuase its right at the end of the road and I don't know where the nearest shell garage is. I get about 34-35mpg becuase I spend all my time driving in town and negotiating the 16 speed ramps in and out of my estate :)

Is it worth seeking out a shell garage and using their diesel? Would I really see a difference as big as 5mpg?
Which Diesel Fuel - andymc {P}
Just for a different perspective, I use 100% biodiesel in my Leon TDi and my Passat TDi, as I did in my BMW 525 TD and my Renault Clio dci. I notice a marginal increase in fuel economy of 3-5 mpg (it's never totally consistent because the feedstock is never exactly the same from batch to batch) as well an increase in power (partly due to higher free oxygen in the fuel) which made the pace of the BMW more tolerable. As it's much more lubricating than ULSD, I don't need to worry about additives for reducing wear & tear. At the moment, I seem to be averaging around 56 mpg without trying. Funnily enough, although the Passat and the Leon have the same engine, the Passat seems to be slightly more economical despite being heavier. That said, the Leon is faster and goes round bends a lot better, so maybe it's just down to driving style.
Which Diesel Fuel - Reggie
I generally use Esso diesel, for my 406 & C3, but have used supermarket and Shell diesel. I always do my m.p.g. and have neither noticed an improvement in economy or smoothness, nor do I ever use injector cleaners etc. Does this mean that I am not "in tune" with my engines and poor at mathematics?
Is there any conclusive evidence to support the premise that Shell diesel IS the highest quality on the market, or is there alot of fokelore involved?
Which Diesel Fuel - keithb
Reggie - I use whichever brand is convenient including many fills of French hypermarket fuel. Despite keeping detailed fuel consumption records, I've never found any difference. Nor have I found any difference in performance, smoothness etc.

I also would not put additives of unknown composition (e.g. Millers) in my car. At best, it's money down the drain and at worst there could be adverse effects on the engine over time. The problem is that no-one knows so it's best to avoid.

BMW 330d by the way.
Which Diesel Fuel - Shortwing Rob

But I simply do not believe the above post.

Where is the evidence? Why isn't there a major campaign to sue the supermarkets?
Unfounded tittle-tattle spreads quickly on the intenet. Let us see the foundation please.

Which Diesel Fuel - Marcos{P}
I borrowed a vito from work to go and pick some furniture up from London and on the way I filled up with diesel at a well known supermarket because I had no option, it was almost empty when I picked it up.
Whilst in London the thing stopped working and would not restart. I carried on turning it over and over and then left it for half an hour. When I then returned to try it started first time so I rushed back to the office with it running like a dog. The mechanics looked at it and said the fuel filter was filled with quite large pieces of filth and could'nt understand where it had come from. I mentioned where I had filled it up and he said it was getting to be quite a common problem with supermarket fuel.

Maybe it's not all unfounded tittle-tattle
Which Diesel Fuel - Shortwing Rob
OK, let's think this through then.

There are only two possible scenarios that I can think of.

1) The supermarkets, past masters at building consumer loyalty and very mindful of their reputation are deliberately specifying a fuel from a supplier knowing that it is injurious to their customers' vehicles in order to pare a couple of pence off each litre and have got their fingers crossed that nobody notices.

2) The fuel suppliers are supplying what must be by an almost infinite distance their largest and most valuable customer (s) with substandard fuel in the belief that, though it wrecks the supermarket's customers vehicles they won't ever be found out and lose their largest customer.

Nope. Still don't buy either of those.

Which Diesel Fuel - Shortwing Rob
And I just noticed the following phrase in the earlier post.

"it was almost empty when I picked it up"

I don't suppose that might have had anything to do with the breakdown? You know, the sludge of ages from the very bottom of the tank?

Which Diesel Fuel - Marcos{P}
When I say empty I mean just below a quarter.

I'm a little over cautious with fuel levels.
Which Diesel Fuel - Reggie
I'm with Shortwing Rob on this one....... that is until my distribution pump fails, then I'll blame it on the French.


Which Diesel Fuel - Dizzy {P}
But I simply do not believe the above post.
Where is the evidence? Why isn't there a major campaign to sue the supermarkets? Unfounded tittle-tattle spreads quickly on the internet. Let us see the foundation please.

Well said, SR.

I've already asked on this forum for the sciencific reasoning behind the claims that "supermarket fuel is bad but Shell is good" but not a shred of solid evidence has been put forward.

Like many others, I detest supermarkets and the way they are putting so many other providers out of business, but that is no reason to make unsupportable (and even libellous?) accusations against them.

Which Diesel Fuel - jonesy127 {P}
I suspect that if one fills up with fuel one expects to be better, one will automatically see an improvement in performance/economy?
Which Diesel Fuel - Marcos{P}
I have just started using Shell diesel and I have definately got an extra 50 miles out of the tankfulls.
I didn't expect it to be any better but as I am keeping an eye on the mpg I noticed the difference.

Coincidence or not
Which Diesel Fuel - Shortwing Rob
I'm confused Marcos

In your first post you implied that you only used supermarket fuel to fill up a vehicle because it was dangerously low (1/4 of a tank!) and you had absolutely no choice.

Now you tell us you have "just started" using Shell.

Something doesn't compute.


Which Diesel Fuel - Marcos{P}
How hard is it to understand.

I borrowed a van and noticed it was low on fuel so had to stop at the nearest petrol station which happened to be a supermarket type as there were no more on the way that I knew of.

Normally I use B.P. or ESSO as they both have outlets near to where I live.

I am running a large site and there is a Shell garage near it so after reading peoples comments I have started filling up there to try Shell's fuel.

Does that compute.

Which Diesel Fuel - pugdriver
I've got to agree with the Shell runners here; I used to use Q8 because I got a discount if we went shopping at the local Waitrose. However, whenever I used Shell it would be noticeable that the engine was a little smoother, and the tankful lasted a bit longer. Not much, but it was definitely noticeable.

I now use Shell diesel all the time - it only costs me 1p/litre more that the local Q8 fuel, and I figure that's worth the difference. Also use Millers at each fill. Using good quality fuel and a recommended additive has kept me clear of injector or pump problems for seven years and over 300,000 miles in various oil burners.
Which Diesel Fuel - Reggie
I have been clear of injector and pump problems on my diesels for in excess of 500,000 miles, and that was using the cheapest fuel available and no addatives, often supermarket fuel, and to confound the French knockers, all in French cars!
Vivre le France!
Which Diesel Fuel - madf
My wife has run her Peugoet 106 diesel on Q8 fuel for 8 out of its 9 years: still 58mpg and no problems. Not a high tech engine tho: I understand at 1 time supermarket diesel had no added lubricants hence the reported pump problems.

Which Diesel Fuel - mark999
The lubricity additive for low sulfur diesel is added at the refinery. The fuel brand additives which contain detergent and
combustion improver are added by the tanker driver.
Some makers diesel distribution pumps were more prone to wear than others (vw/audi).
When low sulfur diesel, without lubricity additive, was introduced in Scandanavia there were reports of many failed fuel pumps. We succesfully reproduced this with a golf tdi within 500 miles of switching to low sulfur fuel.
Which Diesel Fuel - Flat in Fifth
You might remember Dizzy I had a communication with direct with Ford asking for clarification of their statement quoted in the DT "constant use of worst case diesel will lead to problems.."

In the end all they said was as long as the fuel meets EN590 then you will be OK. Since then I always look for the above spec when filling up and have not yet found an outlet which does not comply. That includes supermarket and oil company sites.

I would like to see some independant scientific testing though. Maybe there has been and not reported because it proved nothing.

Value my car