Aughton: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, provided it has not been started. Everyone in Aughton starts with "have I wrecked it?", and the fair answer is generally no: petrol left in the tank of any diesel remains harmless until priming, cranking or driving draws it into your fuel system. Keep it like that: leave your engine off then phone Petrol in Diesel. What petrol actually does to a diesel, how to judge how far it has travelled, and how to stop it from happening a second time: that is the remainder of this page.
Inside your engine: what petrol in a diesel really does
On its way through an engine, diesel does two tasks. It burns, and before it ignites it protects. Built to very fine tolerances, the fuel injectors and your pump rely on the diesel flowing through them to stop their surfaces wearing against one another.
Of these two tasks, petrol manages the first badly and the second not at all. The knocking comes from petrol being designed not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the fuel system depends on, and any pump running on such a blend is wearing itself.
Put these together and the shape of the trouble is clear. Not contact but circulation is what does the harm. A tank with petrol in it is a fuel issue. Once the pump has been labouring on that petrol, a mechanical fault has started: whatever is shed by a pump that is wearing is carried onward to your injectors with the fuel.
How serious is petrol in a diesel? Four situations our engineers see around Aughton
Filled up, and never started: nothing beats it. At a forecourt, and really only there, that petrol is still limited to your tank — because everywhere else the vehicle was driven to reach it. The task is draining and flushing on the spot.
A moment's running, or just the ignition on. The fuel system has been primed, so petrol has left the tank and reached the fuel filter and the fuel lines. Drain, flush, see to the fuel filter: still normally easy.
Your pump has worked a couple of miles on thinned fuel — that's what driving the vehicle meant. How hard the car was driven counts as much as how far, and the work covers the tank, the lines, the filter and fresh fuel through the whole circuit. A school run to Aughton Primary Academy is one matter. Driving as far as Sheffield, under 10 miles away, makes a very different job — as does any miles on the M1, under 3 miles from Aughton, with the engine running hard all the way.
Driven on until it protested — rattling, smoke, an uneven idle, a soft throttle. What you are hearing is your motor reporting fuel that no longer runs like diesel. Pull up wherever you are — the verge on Hall Road, a lay-by, a side street — then leave the vehicle where it is. The drain and flush still come first, and they sort it out: when a car is pulled over soon, long-term damage is very unusual.
Stories Aughton motorists hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. Percentage is not how a diesel fuel system copes with petrol, whatever that guidance presumes.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." Protection matters more on current diesels, not less, because their fuel passes through more precise components at higher pressure.
The myth that catches drivers off guard: if it starts and drives, it must be unharmed. Any petrol motor fed diesel generally won't run, so the motorist stops and the harm stops with them. Feed petrol to a diesel and it usually fires up, idles and pulls away as if nothing has happened — all while its pump is wearing. Fine and running are not the same thing.
Not so: a two-stroke additive makes it safe to drive home. It is an old fix, meant for another problem. None of what petrol diluted gets put back by it — and afterwards, your tank still contains that petrol.
If your engine has run, part of the petrol is in your filter and your lines, not the tank — and the next start sends it right back through your pump. So the myth "drain your tank yourself and you are sorted" doesn't stand up. Emptying petrol into a can by the kerbside is also genuinely hazardous.
Petrol in a diesel: how does it take place?
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 mostly will not go into a petrol car at all. So the mistake runs one way.
When routine and your car stop matching, it happens. A car that is new to you — hired, on loan as a courtesy car, or just bought. Households running one of each, petrol and diesel. Your normal forecourt, its pumps now in a different order. A rushed fill en route to Woodhouse with a train to catch. A new-to-you diesel Volkswagen Tiguan, its first fuelling, and a motorist accustomed to petrol: exactly when it takes place. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
How to avoid petrol in a diesel at your next fill-up around Aughton
- A green handle for unleaded and black for diesel is normal in the UK — but not on every forecourt. Go by the label on the petrol pump, not the colour.
- Many cars state the fuel inside the filler flap or on the cap, so check there on the first fill in any car you do not know.
- A coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember, for a household with one of each.
- It seems daft and it works: on the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump.
- Put the phone away. This is an easy mistake to make whilst you are thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to refuse a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop checking the pump.
- Stop as soon as you notice. Less petrol inside the tank makes a weaker mix. It does not change what to do next, which is still not to fire it up.
Aughton: already put petrol in a diesel?
Then the order of things is brief. Starting it is out, and so is turning on the ignition. Still at the forecourt, at the nearest petrol station or anywhere else? Ask the attendants to help you push the car clear of the pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it's been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different problem — Aughton has a page just for it.
Why one petrol in a diesel task around Aughton costs more than another
Four separate jobs sit behind the four situations above — which is why there's no honest single price. Mostly, the cost shifts with which one you're in. Two things come after that: the petrol that got in as a share of what that tank holds, then the spot the vehicle is in and whether a technician can reach it safely.
That is why our engineers ask three questions before costing rather than after: what got in, how much, and if it's run. A range becomes a straight figure when the answers are in.
About Aughton and its setting
Aughton is a village in South Yorkshire, situated on the riverside at an elevation of 98 metres, with detached housing being the predominant type of accommodation. Aughton lies approximately 6 miles from Sheffield and is surrounded by nearby places such as Swallownest, Ulley, and Aston. Aughton has a population of around 2293 residents and is located in a scenic area near the River Rother. Aughton is also relatively distant from London, being around 138 miles away.
Fuel drain cover across South Yorkshire, Aughton included
Aughton sits in the S postcode area, and the teams that answer petrol in diesel calls there work the spots around it as well — Swallownest, Ulley and Aston among them. The vehicle does not need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Aughton: still at the petrol pump?
In that case, you couldn't be in a better position. Leave the vehicle switched off, then ring.