Should You Worry? Petrol in a Diesel Car in Little London
Unstarted? Then less anxious than you probably feel. Petrol resting in a diesel tank does nothing to your engine till something draws it through the system — the ignition priming your pump, the starter, or driving itself. So the honest answer to the first question everyone around Little London asks, "have I ruined it?", is generally no. Leave your engine off then ring Petrol in Diesel — that keeps it that way. What petrol really does to a diesel, how to gauge how far it's travelled, and how to keep it from happening a second time: that is the rest of this page.
Inside your engine: what petrol in a diesel does
On its way through an engine, diesel has two tasks. It lubricates first, and after that does it burn. Designed to very fine gaps, the injectors and the pump rely on the diesel moving through them to stop their surfaces wearing against one another.
Of those two tasks, petrol handles the first badly and the second never. A pump working on a petrol blend is wearing itself out, since petrol is thinner than diesel and takes away the protection your fuel system depends on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where the clattering comes.
The shape of the problem is plain once you put those together. Contact does not do the harm — movement does. Where the petrol is only in the tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds travels on, carried by your fuel, into the fuel injectors downstream, which is why a pump that has been working on that petrol is where a mechanical fault begins.
Four situations our engineers see around Little London: how serious is petrol in a diesel?
Filled but not once started — the best it gets. The petrol is inside the tank and just that tank, and the task is a drain and a flush where the vehicle sits. This is the one situation that can only truly take place on a forecourt, since anywhere else your car has been driven to get there.
Started for a moment, or only the ignition on. Petrol has left your tank and reached the fuel filter and the fuel lines, since the fuel system has been primed. Drain, flush, see to the filter: still usually simple.
Those few miles driven meant your pump running on fuel thinned by petrol the whole way. Tank, lines, filter, then clean fuel run through the whole system: that is this work, and the way the vehicle was driven counts as much as the mileage. The school run to Little London Academy is one matter. Very different once more: a run to Leeds, under a mile away, or some miles on the A64(M), under a mile from Little London, where the engine never stopped working hard.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven until it complained. The motor is telling you the fuel is no longer acting like diesel. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Oatland Lane. Permanent damage is very unusual when a car is stopped early, and the fuel drain and flush-through that still come first sort it out.
Petrol in a diesel myths Little London motorists hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing is removed when you top up — that tank simply holds more of the same mixture. The assumption behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Newer diesels can handle a little petrol" — a myth, and nearer the reverse. A modern diesel runs its fuel through smaller parts at higher pressure, which makes the protection count more, not less.
The myth that catches people out: if it starts and drives, it must be unharmed. A petrol motor fed diesel usually won't run, so the motorist stops and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump wears. Fine and running aren't the same at all.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate issue. What petrol has weakened stays thinned, and that petrol remains inside your tank regardless.
The next start draws petrol back round the pump from the lines and the fuel filter, where some of that sits once the engine has run. That's why draining the tank yourself does not sort it — a myth. On top of that, petrol cleared into a can by the road is genuinely hazardous.
Why petrol in a diesel occurs at all
It's seldom carelessness, and no one does it on purpose. The forecourt makes it simple: the petrol nozzle is the slimmer of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally will not go into a petrol motor at all. So the error runs one way.
The moment habit stops matching the car is the moment it takes place. Courtesy car, hire car, or a motor that's brand new. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. A train to catch, and a rushed fill on the way to Leeds. A new-to-you diesel Volkswagen Tiguan, its first fuelling, and a driver used to petrol: precisely when it occurs. Throw in a back seat full of children, a phone call or rain, and habit wins.
How to avoid petrol in a diesel on your next fill-up in Little London
- The label is what counts, and so check the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, yet not on every forecourt.
- Plenty of motors state the fuel inside the filler flap or on the cap, and so check there on the first fill in any vehicle you do not know.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, in a house with one of each.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car gets its first tank. It seems daft. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away then keep your mind on the petrol pump.
- Add-on devices exist for cars without one, and some diesels come with a filler that won't take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Stop as soon as you realise. Less petrol inside the tank means a weaker mix. It does not change what to do next, which is still not to crank it.
Already put petrol in a diesel in Little London?
Short and simple, then, is the order of things. Don't crank it, and do not turn the ignition on. The staff on the forecourt — whether at Shell itself or wherever you filled up — will normally help roll it clear of the pump if you ask. Then ring 0333 366 0103 and tell us what got in, about how much, and if it's run.
If it was AdBlue and not petrol, say so. That is a different issue — corrosion and deposits instead of lost protection — and it has its own page for Little London.
Why one petrol in a diesel task around Little London costs more than another
Four different tasks lie behind the four situations above — which is why there's no honest single price. Which of them you are in is mostly what shifts your cost. Next it is the proportion — how much petrol went in against how much the tank holds — and after that where the car is and whether a technician can get to it safely.
That's why our technicians ask three queries before costing instead of after: what went in, how much, and if it has run. A range turns into a straight figure when the replies are in.
About Little London
Little London is a suburban area in West Yorkshire, situated on the riverside near Leeds, with a mix of residential and commercial properties. Little London has a relatively low elevation of 54 metres and is located close to other nearby places such as Bagby Fields and The Leylands. Little London is predominantly composed of flat-type housing, which is common in urban areas like this. Little London is also close to Sheepscar, another nearby suburb of Leeds.
Little London and West Yorkshire: where our fuel drain cover runs
Petrol in diesel call-outs around Little London — part of the LS postcode area — go to teams that likewise cover the locations round it, Bagby Fields, The Leylands and Sheepscar among them. The car does not need to come to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the petrol pump in Little London, right now?
The best place there is, then — that's where you are. Switched off it stays; then ring.