--- title: Shothole: Petrol in a Diesel Car, Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/shothole-dorset/ location: Shothole county: Dorset latitude: 50.854510 longitude: -2.204110 service: Petrol in a Diesel Car updated: 2026-10-04 --- # How Worried Should You Be? Petrol in a Diesel Car in Shothole Probably less than you already are — provided no one has started the vehicle. Till the ignition primes your pump, the starter cranks, or your vehicle is driven, petrol in a diesel tank just waits there and does nothing. Which means the honest reply to that first Shothole query — "have I wrecked it?" — usually no. To leave the vehicle like that, phone Petrol in Diesel and leave your motor alone. Further down, this page sets out what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you a second time. ## Your engine and petrol in a diesel: what happens Passing through a motor, diesel does two jobs at the same time. Before it ignites, it lubricates — then it combusts. The high-pressure pump and your injectors are built to very fine clearances, and the diesel passing through them is what stops those surfaces from wearing against one another. The second task petrol does not do at all, and the first it does badly. A pump working on a petrol mixture 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 needs from its fuel — and that's where any rattling comes. Put these together and the shape of the issue is clear. Contact does not do the damage — circulation does. Where the petrol is only in that tank, it's a problem of fuel, nothing more. Whatever a worn pump sheds travels on, carried by your fuel, into the injectors downstream, which is why a pump that has worked on the petrol is where a mechanical problem begins. ## How serious is petrol in a diesel? Four scenarios our technicians see around Shothole The best case there can be: filled up, never started. Only that tank has petrol in it, and so the task is draining the tank and cleaning your system where your car sits. This scenario can only really take place on a forecourt: anywhere else, your car got there by being driven. The ignition switched on, or a brief start. Once primed, your system has drawn petrol out of the tank as far as your filter and the lines. Drain, flush, see to your filter: still usually simple. Your pump now spent a couple of miles on thinned fuel — that's what driving the vehicle meant. Tank, lines, filter, then clean fuel run through the whole circuit: that's this work, and the way your car was driven matters as much as the distance. A school run to Durweston Church of England Primary School is one thing. Any mileage on the M27, under 50 miles from Shothole, means the motor working hard throughout, and a run to Salisbury, under 25 miles away, is a very different job too. Driven on till it complained — clattering, smoke, a ragged idle, a dead throttle. What you are hearing is the motor reporting fuel that no longer acts like diesel. Leave it wherever it stops: a lay-by, a side street, the verge on Fair Mile Road. Lasting damage is very unusual if a vehicle is pulled over early, and the fuel drain and flush-through that still come first deal with it. ## Myths Shothole motorists hear about petrol in a diesel It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing comes out when you top up — that tank just holds more of the same blend. The idea behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong. "Current diesels can handle a little petrol" — a myth, and nearer the reverse. Lubrication matters more on modern diesels, not less, because their fuel passes through finer parts at higher pressure. This is the one that catches motorists. Myth: "If it starts and drives, there's no damage done." A petrol motor fed diesel generally will not run, so the driver stops and the damage stops with them. Feed petrol to a diesel and it normally starts, ticks over and pulls away as if nothing happened — all while its pump wears. Fine and running aren't the same at all. Myth: "Add some two-stroke oil and drive it home." It's an old fix for a separate issue. It does not put back what petrol has diluted, and the petrol is still in the tank later on. Myth: "Drain your tank yourself and you are sorted." Once your engine has run, some of the petrol is no longer in the tank: it's in the fuel filter and the lines, and it goes right back through the pump on your next start. And, a can of petrol filled by the roadside is genuinely hazardous. ## How it happens: petrol in a diesel On purpose? Never. Through carelessness? Rarely, if ever. One way only, since of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one mostly won't fit a petrol motor. That's how the forecourt makes it simple. Routine and the car getting out of step is how it occurs. Courtesy car, hire car, or a motor that is brand new. Two motors on one driveway, one petrol, one diesel. A forecourt you know, but with its pumps arranged differently. A train to catch, and a rushed fill on the way to Holton Heath. Years of petrol motors behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that's when. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of children. ## Shothole people: how to avoid petrol in a diesel next time - Read the pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on each forecourt. The label is what counts. - The first fill in a strange car is the time to check the filler flap — inside it, or on the cap, many vehicles state which fuel to use. - Mark your key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember. - Before the nozzle comes off the petrol pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Silly, perhaps, but it does the trick. - Whilst you are thinking about something else, this is an easy mistake to make — so put your phone away. - Add-on devices are available for cars without one, and some diesels are built with a filler that will not accept a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label. - Stop the moment you notice. Less petrol inside the tank makes a thinner mix. It doesn't change what to do next, which is still not to crank it. ## Put petrol in a diesel around Shothole already? The order of things is short, then. Do not start it, and do not switch the ignition on. The staff at the forecourt — whether at Tesco itself or wherever you filled up — will normally help push it away from the petrol pump if you ask. Then phone 0333 366 0103 and tell us what went in, roughly how much, and if it's run. AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a separate problem — Shothole has a page all for it. ## Shothole petrol in a diesel tasks: why one costs more than another There is no fair single quote for this, because the four situations above are four separate tasks. What moves your cost is mostly which of them you are in. Where the vehicle is matters too, and whether our van can safely reach it, after the proportion of petrol to what your tank holds. That is why our engineers ask three queries before quoting rather than after: what was put in, how much, and if it's run. The replies change a range into a straight figure. ## About Shothole itself Shothole is a small hamlet in Dorset, situated inland at an elevation of 122 metres, and is located near the villages of Quarleston and Bryanston. Shothole lies approximately 23 miles from Salisbury and 100 miles from London, placing it in a rural setting within the South West region. Shothole has a population of around 999 residents, with semi-detached housing being the predominant type in the area. Shothole is surrounded by rolling countryside, with nearby Durweston also being a neighbouring settlement. ## Fuel drain cover across Dorset, Shothole included The teams answering petrol in diesel calls in Shothole, in the DT postcode area, equally work the spots around it, Quarleston, Bryanston and Durweston included. The car doesn't need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway. ## At the pump around Shothole, still? The best place there is, then — that is where you are. Leave the vehicle switched off, and ring.