Goxhill: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, provided it hasn't been started. Petrol sitting in a diesel tank does nothing to your motor till something pulls it through the fuel system — the ignition priming the pump, the starter, or the drive itself. So the fair answer to the first query everyone around Goxhill asks, "have I ruined it?", is usually no. Keep it like that: leave the motor off then call Petrol in Diesel. The remainder of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you a second time.
Inside the engine: what petrol in a diesel does
Diesel has two tasks on its way through a motor. It lubricates to begin with, and after that does it burn. Extremely fine tolerances are built into the injectors and your high-pressure pump, and only the diesel flowing through stops those surfaces grinding together.
Poorly at the first, not at all at the second: that's petrol. The rattling comes from petrol being made 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 protection your system depends on, and any pump working on that mix is wearing itself.
Put these together and the shape of the trouble is clear. Not contact but movement is what does the harm. Any tank with petrol in it is a fuel problem. Whatever a worn pump sheds goes on, borne by the fuel, into the fuel injectors downstream, which is why a pump that has worked on that petrol is where a mechanical problem starts.
Four situations our engineers see around Goxhill: how bad is petrol in a diesel?
Filled but never started — the best it gets. On a forecourt, and really only there, the petrol is still confined to that tank — since anywhere else the vehicle was driven to reach it. The job is emptying and rinsing on the spot.
Started for a second, or just your ignition on. Once primed, your system has pulled petrol from your tank up to your filter and your lines. That is usually still an easy task — a drain, a flush, and the filter dealt with.
Driven a couple of miles. Now your pump has spent those miles labouring on weakened fuel. How hard the car was driven counts as much as how far, and the work takes in the tank, your lines, the filter and clean fuel through the entire circuit. The school run to Goxhill Primary School is one thing. Any miles on the M180, under 10 miles from Goxhill, means the motor has worked hard throughout, and a run to Kingston upon Hull, under 5 miles away, is a very different job as well.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The motor is telling you your fuel is no longer acting like diesel. Stop wherever you are — the verge on Thorn Lane, a lay-by, a side street — then leave it where it is. Long-term damage is very uncommon if a vehicle is stopped soon, and the fuel drain and flush that still come first take care of it.
What Goxhill drivers get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up takes out nothing; it gives you a bigger tank of the same mix. That guidance assumes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. Finer components and higher pressure are the way a newer diesel runs its fuel, and that makes the protection count more, not less.
"It starts, it drives, and so no harm done" — the myth that catches more drivers than any other. Any petrol motor fed diesel normally won't run, so the motorist stops and the damage stops with them. Feed petrol to a diesel and it generally starts, ticks over and pulls away as if nothing happened — all while its pump is wearing. Being able to run is not the same as being fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, supposed for another fault. It does not put back what petrol has thinned, and the petrol is still inside the tank after that.
The next start sends petrol back round your pump from the fuel lines and the filter, where some of that sits after your engine has run. That's why a DIY tank drain doesn't leave you sorted — a myth. On top of that, petrol drained into a can by the road is truly risky.
How petrol ends up: petrol in a diesel
No one does it on purpose, and it's seldom carelessness. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol motor at all. The forecourt makes it easy, and the slip runs one way.
Habit and the vehicle getting out of step is how it occurs. Courtesy car, hire car, or a car that is brand new. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. Rushing for a train at the nearest station and fuelling up en route. Exactly the moment it happens: after years of driving petrol, someone fills a diesel Renault Clio for the first time. Add rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Preventing petrol in a diesel next time you fill up in Goxhill
- Check the pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on each forecourt. The label is what matters.
- Many vehicles state the fuel inside the filler flap or on the cap, and so check there on your first fill in a car you do not know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of intending to remember, for a house with one of each.
- "Diesel", out loud, before you pick up the nozzle — every time a new or hired car gets its first tank. It sounds daft. It works.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away then keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop checking the pump.
- Stop as soon as you notice. Less petrol in your tank means a thinner mix. It doesn't change what to do next, which is still not to start the car.
Put petrol in a diesel around Goxhill already?
Then, there's just a short order of things. Do not crank it, and do not turn your ignition on. The staff on the forecourt — whether at Esso itself or wherever you filled up — will normally help push it clear of the pump if you ask. Phone 0333 366 0103 next, with three answers — your fuel, the approximate volume, and if it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different issue — Goxhill has a page all for it.
What makes one Goxhill petrol in a diesel job cost more than the next
Four different jobs sit behind the four scenarios above — which is why there is no fair single quote. What moves the cost is chiefly which of them you're in. Next it's the ratio — how much petrol got in against how much that tank takes — and after that where the vehicle is and whether a technician can reach it safely.
Three questions come first, before any quote, rather than after — what got in, how much, has it run — and that is the reason. The answers change a range into a straight figure.
About Goxhill and its setting
Goxhill is a small village in northern Lincolnshire, situated near the coast and close to the city of Kingston upon Hull. Goxhill has a population of around 1245 people and is characterised by detached housing. Goxhill sits at a low elevation of 13 metres above sea level, looking out over the surrounding countryside and towards the nearby North Sea coast.
Goxhill and Lincolnshire: where our fuel drain cover runs
North End, South End and The Hallands are among the spots around Goxhill that the same vans work, answering petrol in diesel calls across Goxhill's DN postcode area. The car doesn't need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
In Goxhill and still at the pump?
Nothing beats it: that is where you are. Turned off it stays; then ring.