--- title: Petrol in a Diesel Car Long Ashton — Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/long-ashton-somerset/ location: Long Ashton county: Somerset latitude: 51.429600 longitude: -2.662400 service: Petrol in a Diesel Car updated: 2026-10-03 --- # Long Ashton: Petrol in a Diesel Car? How Worried to Be Probably less than you already are — as long as nobody has started it. Until the ignition primes the pump, the starter turns, or your car is driven, petrol in a diesel tank just rests there and does no harm. Which makes the honest reply to the first Long Ashton question — "have I wrecked it?" — normally no. To leave the vehicle that way, call Petrol in Diesel then leave your motor switched off. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and the way to make sure you don't do it again. ## Inside the motor: what petrol in a diesel really does Diesel does two jobs on its way through an engine. It ignites, and before it burns it lubricates. Your high-pressure pump and your injectors are made to very fine clearances, and your diesel passing through them is what keeps those surfaces from wearing against each other. Petrol does the first job poorly and the second not at all. The rattling comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips out the protection the fuel system hinges on, and any pump working on that mixture is wearing itself. Taken together, they make clear what shape the trouble takes. Not contact but movement is what does the harm. A tank with petrol in it is a fuel issue. The start of a mechanical problem is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with the fuel to the injectors downstream. ## How serious is petrol in a diesel? Four scenarios our engineers see around Long Ashton The best case there is: filled up, never started. That petrol is in your tank and only the tank, and the task is a drain and a flush where your car stands. This is the one situation that can only really occur on a forecourt, since anywhere else the vehicle has been driven to get there. Ignition on, or started for a second. With the fuel system primed, your lines and filter now hold petrol that has come from your tank. Usually nothing more than draining, cleaning and sorting your filter, and so still straightforward. Some miles driven, and the pump has spent every one of them running on diluted fuel. The work is the tank, your lines, your filter and clean fuel through the whole circuit, and how hard the car was driven counts as much as how far. On the school run to Birdwell Primary School, the distance is short. Any miles on the M5, under 5 miles from Long Ashton, means the engine has worked hard throughout, and a run to Bristol, under 5 miles away, is a very different job too. It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone lumpy. That's your engine telling you its fuel no longer is acting like diesel. Pull up where you are — on the verge on Weston Road, at the kerb, down a side road — and don't move it. Long-term damage is very uncommon when a car is stopped soon, and the drain and flush that still go first deal with it. ## What Long Ashton drivers get told about petrol in a diesel — and the myths in it It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Topping up takes out nothing; it gives you a bigger tank of the same mix. The idea behind that advice — that diesel fuel systems accept petrol by percentage — is wrong. Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. At higher pressure, through smaller parts: that is how a modern diesel handles its fuel, and so the lubrication counts for more, not less. The myth that catches people off guard: if it starts and drives, it must be unharmed. A petrol motor fed diesel generally won't run, so the motorist stops and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump wears. Running is not the same as fine. Not so: a two-stroke additive lets you to drive home. It was an old fix, meant for another problem. It doesn't put back what petrol has diluted, and that petrol is still inside your tank later. Once the engine has run, part of that petrol is in the fuel filter and the fuel lines, not the tank — and the next start pulls it straight back through the pump. So the myth "drain the tank yourself and you are sorted" does not hold. Emptying petrol into a can by the roadside is also truly dangerous. ## How does petrol in a diesel occur? Nobody does it on purpose, and it's seldom carelessness. A diesel nozzle mostly won't fit a petrol motor, yet the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake easy, and just in that direction. Routine and the car falling out of step is how it takes place. Hire cars, courtesy cars, and vehicles that are new to you. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. A train to catch, and a hurried fill en route to Parson Street. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. With rain, a call arriving, or a car full of children to deal with, the hand simply does what it always has. ## Long Ashton motorists: how to prevent petrol in a diesel next time - Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Read the pump's label; the colour is just a hint. - In a motor you do not know, look inside the flap over the filler or at the cap before the first fill: plenty of motors print the fuel there. - A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, for a house with one of each. - Before the nozzle leaves the pump the first time you fill a hired or new car, say "diesel" aloud. Silly, perhaps, but it does the trick. - Put your phone away. This is an easy mistake to make while you're thinking about something else. - Some diesels have a filler designed to reject a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the petrol pump. - Noticing it halfway? Stop there and then. A weaker mix results from less petrol in your tank, but your next stage remains the same: don't start it. ## Already put petrol in a diesel around Long Ashton? Then the order of things is brief. Don't turn the ignition on, and do not fire it up. Still on the forecourt, at Shell or anywhere else? Ask the attendants to help you push the car clear of the petrol pump. Next, 0333 366 0103. We'll ask what went in, roughly how much, and if it's been run. AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different problem — Long Ashton has a page all for it. ## What makes one Long Ashton petrol in a diesel job cost more than the next The four situations above are four separate jobs, so no single quote for this would be honest. Which of them you're in is chiefly what shifts the cost. Next it's the proportion — how much petrol was put in against how much that tank takes — and after that where the vehicle is and whether a van can reach it safely. Three questions come first, before quoting, instead of after — what went in, how much, has it run — and this is the reason. The replies turn a range into a straight figure. ## About Long Ashton, briefly Long Ashton is a village situated on the riverside in Somerset, with a mix of semi-detached housing and other residential properties. Long Ashton lies close to the city of Bristol, approximately 3 miles to the south west, and is surrounded by nearby places such as Yanley and Ashton Watering. Long Ashton has a population of around 2910 people and is located at an elevation of 57 metres above sea level. Long Ashton is also within commuting distance of major cities, with London being around 109 miles to the east. ## Long Ashton and Somerset: where our fuel drain cover runs Petrol in diesel calls in Long Ashton — part of the BS postcode area — go to vans that also cover the locations round it, Yanley, Ashton Watering and Cambridge Batch among them. The vehicle does not need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway. ## Long Ashton: still at the pump? Then, you couldn't be in a better place. Phone, and leave it switched off.