Whilst the branded filling stations normally have their own, I do recall a previous thread in the Backroom saying that often the contents of those lorries are the same (per region as you say - coming from X or Y refinery/distribution centre) and the cleaning additives specific to the filling station brand (or supermarket) get added (mixed) when they get pumped into the storage tanks at the destination.

Oh Andy, no no no.

I can say with absolute certainty that this does not happen!

I work at a petrol station p/t

Apart from the potential to go wrong, can you imagine tankers lugging round the extra weight of various additives.

I was only stating what had been said previously - not saying it was the case. If that's so, why do some supermarket filling stations get fuel from branded (e.g. Esso, Shell, etc) tanker lorries, sometimes different ones (which I've seen)?

Does that also mean that a tanker lorry only ever visits either one filling station and completely empties, or only visits filling stations of one firm, i.e. that sells the same mix of fuel and additives?

Given the additives would presumably be mixed into 'standard' fuels at some point before the pump, how do they get mixed? a Big vat of known amount of fuel, add the cleaning additive, mix using some stirrer device for Z time, then dispence?

I was originally thinking (if they were mixed at the filling station) that the mix (the additive would be very small in level and could easily be delivered either completely separately or via small secondary tanks) could be done similarly to that of the carbonated water and syrup used in pubs and bars to make colas, etc instead of buying in bottles and cans.

Tanker contents afaia are the same, the additives I`m told are made at the refineries and added to the tanker on fillup of tanker, not at the garage.

Most filling stations offer regular and premium varieties of both petrol and diesel. The larger road tankers - and perhaps the smaller ones too - have two, perhaps more, compartments for different fuels. I don't know whether any vehicles have four compartments, but clearly that number can be reduced by treating a delivery on arrival with appropriate additives. I don't see why that operation can't be managed reliably, say by tipping 250ml of super-special Stuff into the tank before pumping 3 tons of plain petrol on top to ensure mixing.

And if true, it suggests that the blame for the tale of dirty fuel from a Tesco supermarket may be on the supplier, not the supermarket, unless their tank got flooded with water somehow ?

If you are referring to the many claims c.15 years ago against Tesco (and others? I can't recall) for damaged lamda sensors, that was apparently due to a tanker load of petrol from the Vopak tank farm in Rotterdam and distributed by Greenergy that had at some stage been contaminated. A silicon anti-foaming agent for diesel fuel was mistakenly added to the petrol, and once in the cars had the effect of leaving a 'glass' coating on the hot sensors that prevented them working.

If this reveals anything it is that it doesn't all come from the same tank - I don't think that branded fuel in general was affected on that occasion - probably because it was limited to one distributor.

I am aware that there was also a story about compo being paid by Tesco for damage caused by water in petrol, around the same time, but that might have been just one station.

I have a book on automotive engines published in the US in 1994 which acknowledges all motor manufacturers and component makers current in the US at that time for information and illustrations.

There is an 8 page chapter on fuels and combustion, which states that "engines can run on 90% unleaded petrol and 10% ethanol without any change to the vehicle fuel system".

What it goes on to say is that methanol can also be used, but "this fuel is highly toxic and corrosive, attacking aluminium, solder, plastics and other materials".

Is the corrosive reputation of ethanol due to experience with "industrial alcohol" which is commonly denatured with methanol in the UK?

After all this discussion I have to recall HJ 's recommendation long before the changeover happened and it was look up your nearest Esso garage and fill up with their super unleaded. Only problem is finding Esso filling stations these days as the supermarkets hold the major share of fuel sales.

Maybe they are more regional-based. I'm lucky with one (only two including Tesco - next door) and another two 12 miles away.

What's the difference between their super unleaded fuel and other major branded ones like Shell, Teaco and BP? Is it 100% petrol, and will that be allowed? I bet it won't be cheap.

With one exception (ExxonMobile - Esso) the major oil companies closed or sold off their UK refineries long ago leaving just 5 or 6 operational. However, long before that all companies used the nearest refinery because it would be crazy to drive tanker loads of fuel all over the country. We also import petrol but again it makes more sense to use the closest appropriate terminal.

No idea if it is still true but when the supermarkets first opened filling stations they often bought imports on the spot market to get low prices, leading to a greater risk of contamination. Apart from this all the regular grades of petrol are the same at everywhere other than their additive packages. Diesel can be an exception because the biofuels (not ethanol) which now have to be blended are highly variable so a refinery can end up with a rogue batch causing problems such as cold weather starting.

I remember often seeing - especially over the last 5-10 years, oil tankers laying off Plymouth Sound when I was holidaying in the region. I presume that was for whoever buying/selling to wait for prices to go in their favour.

It certainly makes sense for as much fuel to be sourced from the most local refinery/distribution centre and just add any cleaning additives at a convenient time when it gets transported to the filling station.

It'll be also interesting to see if Esso deliberately markets their superunleaded for use with older cars that cannot acccept E10 as well as the usual performance cars. Shell in particular appear to have previously got their ad campaigns tailored to 'performance car' owners. If theirs now goes to E10 (it may be E5), they may lose some custom, though likely not much given the overal mix of purchases.

According to the You tube clip from the Aston Martin specialist , Esso super unleaded is pure petrol with no ethanol so that’s where I’m heading in future !

I wouldn't necessarily believe that. I think I read somewhere further up this thread that super unleaded must contain up to 5% ethanol from the first of September.

I understood that some super unleaded used to contain no ethanol before Septtember the first, depending on which refinery it came from.