--- title: Explained: Petrol in a Diesel Car Feeny canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/feeny-county-londonderry/ location: Feeny county: County Londonderry latitude: 54.893000 longitude: -7.022000 service: Petrol in a Diesel Car updated: 2026-10-20 --- # How Worried Should You Be? Petrol in a Diesel Car in Feeny Far less than you probably are, provided it hasn't been started. Everyone around Feeny starts with "have I ruined it?", and the honest answer is generally no: petrol left inside that tank of a diesel remains harmless till priming, cranking or driving pulls it into the system. Petrol in Diesel is who to ring, with the motor left off, and so it remains that way. Further down, you will find what petrol actually does inside a diesel, how far it may have got, and how to stop it happening to you again. ## Inside your engine: what petrol in a diesel really does On its way through a motor, diesel does two tasks. Before it combusts, it lubricates — then it ignites. Designed to extremely fine clearances, your injectors and your pump rely on your diesel flowing through them to keep their surfaces from wearing against one another. The second task petrol does not do at all, and the first it does poorly. The clattering comes from petrol being designed not to ignite when compressed, which is exactly the opposite 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 such a mix is wearing itself. Combined, those make the shape of the issue clear. Contact doesn't do the harm — movement does. All a tank with petrol in it amounts to is a fuel fault. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the injectors downstream. ## Feeny, petrol in a diesel: four cases, from mild to major Fuelled, and never started: no case is better. The petrol is in the tank and only your tank, and the job is a drain and a flush where the car sits. This is the one situation that can only really take place on a forecourt, because anywhere else the vehicle has been driven to get there. A brief spell of running, or merely the ignition on. Once primed, the system has pulled petrol from your tank as far as the filter and the lines. Still generally straightforward: drain, flush, and your filter seen to. Those few miles on the road meant your pump labouring on fuel thinned by petrol the whole way. How hard the vehicle was driven counts as much as how far, and the work takes in that tank, the lines, the filter and fresh fuel through the whole circuit. Driving the kids to the local primary school is one sort of trip. Driving as far as Derry, under 15 miles away, makes a very different task — as does any mileage on the M77, over 50 miles from Feeny, with the engine working hard all the way. Clattering, a lumpy idle, smoke, a throttle gone soft: driven till it complained. What you are hearing is your engine signalling fuel that no longer runs like diesel. Stop wherever you are — the verge on Crown Street, a lay-by, a side street — and leave it where it is. What comes first is still the drain and flush-through, and that deals with it, with lasting damage very rare if a car is stopped soon. ## Petrol in a diesel stories Feeny drivers hear It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Topping up removes nothing; it gives you a fuller tank of the same mix. Percentage isn't how a diesel fuel system tolerates petrol, however much that advice supposes. If anything, the reverse is true. Myth: "A current diesel can cope with a bit of petrol." Protection counts more on current diesels, not less, because their fuel passes through finer components at higher pressure. One myth that catches drivers off guard: if it starts and drives, it must be unharmed. The motorist of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the damage stops there. A diesel fed petrol generally starts, idles and drives away as though nothing has happened, while your pump wears. A running engine does not mean fine. Myth: "Add some two-stroke oil and drive the vehicle home." It is an outdated fix for a separate fault. The petrol is still inside your tank after that, and what it has weakened isn't put back. Myth: "Drain that tank yourself and you are sorted." After your engine has run, some of the petrol is no longer inside the tank: it is in your filter and the fuel lines, and it goes right back through the pump on the next start. Emptying petrol into a can at the kerbside is also genuinely risky. ## How does petrol in a diesel take place? On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle mostly will not fit a petrol motor, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake easy, and just in that direction. The moment routine stops matching your car is the moment it takes place. Courtesy car, hire car, or a car that is new. Two vehicles on one driveway, one petrol, one diesel. The pumps in a different order on a familiar forecourt. Racing for a train at the nearest station and filling up en route. A new-to-you diesel Renault Clio, its first fuelling, and a driver used 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 prevent petrol in a diesel on your next fill-up in Feeny - The label is what matters, and so check the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, yet not on each forecourt. - The first fill in a new motor is the time to check your filler flap — inside it, or on the cap, many vehicles state which fuel they take. - One of each in the house? Mark the key to your diesel — a coloured fob, a sticker — since intending to remember is not enough. - Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump. It sounds silly and it does the trick. - Thinking about something else is when this becomes an easy mistake to make, so tuck your phone away then keep your mind on the pump. - Add-on devices are available for vehicles without one, and some diesels come with a filler that won't accept a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label. - Stop as soon as you notice. Less petrol inside the tank means a weaker mixture. It does not change what to do next, which is still not to fire it up. ## Already put petrol in a diesel in Feeny? Short and simple, then, is the order of things. Starting it is out, and so is switching on your ignition. Ask the attendants to help you roll it away from the petrol pump if you are still at the forecourt, whether that is the nearest petrol station or anywhere else. Next, 0333 366 0103. We will ask what was put in, about how much, and if it has been run. Say so if it was AdBlue instead of petrol: it's a separate fault, with its own page for Feeny, since AdBlue brings corrosion and deposits instead of lost lubrication. ## Feeny petrol in a diesel jobs: why one costs more than another An honest single quote doesn't exist here: four situations, four separate jobs. The situation itself does most of the work of moving the cost. Where your car is matters too, and whether a technician can safely reach it, after the share of petrol to what that tank holds. That is why our technicians ask three questions before pricing rather than after: what was put in, how much, and whether it's run. With the answers, you get a straight figure rather than a range. ## About Feeny, briefly Feeny is a small locality in County Londonderry, situated inland at an elevation of 149 metres, approximately 13 miles from Derry. Feeny lies near the villages of Banagher and Straidarran, and is characterized by its semi-detached housing stock. Feeny is a relatively small community, with a population of around 702 people, and is located about 368 miles northwest of London. ## Fuel drain cover in Feeny and across County Londonderry Petrol in diesel calls around Feeny — part of the BT postcode area — go to teams that also cover the places about it, Banagher, Straidarran and Park included. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots our engineers work, and the vehicle does not need to come to us. ## Still at the pump in Feeny? Then, you could not be in a better position. Switched off it stays; then ring.