--- title: Explained: Petrol in a Diesel Car Ratby canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/ratby-leicestershire/ location: Ratby county: Leicestershire latitude: 52.648300 longitude: -1.245330 service: Petrol in a Diesel Car updated: 2026-10-12 --- # Ratby: Petrol in a Diesel Car? How Worried to Be Less than you likely are, provided it hasn't been started. Till the ignition primes your pump, the starter cranks, or the vehicle is driven, petrol in a diesel tank just sits there and does no harm. Which makes the honest reply to the first Ratby question — "have I ruined it?" — normally no. Leave your motor off then phone Petrol in Diesel — that is how you keep it like that. Below, this page sets out what petrol really does inside a diesel, how far it might have gone, and how to stop it happening to you again. ## Petrol in a diesel: what does it do to your engine? Passing through a motor, diesel is doing two jobs at once. Oiling comes before burning; it does both. What stops the surfaces inside the high-pressure pump and the injectors from wearing against one another is the diesel flowing through them — they are built to extremely fine clearances. The second job petrol doesn't do at all, and the first it does badly. It's runnier than diesel and removes the protection the system hinges on, so a pump running on a petrol mix is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the clattering comes from. The shape of the problem is clear when you put those together. It is movement that does the damage, not contact. Petrol in the tank is a fuel problem. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to the fuel injectors further on. ## Petrol in a diesel around Ratby: how serious is it? Four situations The best case there is: filled up, not once started. Being on a forecourt is what makes this the case: elsewhere, your car has been driven there to begin with. With that petrol held inside that tank alone, it is cleared and flushed on the spot, and nothing more is needed. A moment's running, or just your ignition on. Once primed, the fuel system has drawn petrol out of your tank up to the fuel filter and your lines. That is normally still an easy task — a drain, a flush, and the filter seen to. The pump has spent a couple of miles on thinned fuel — that is what driving the car meant. Tank, lines, filter, then fresh fuel run through the entire system: that is this work, and the way the vehicle was driven counts as much as the distance. Driving the children to Ratby Primary School is one sort of trip. Very different again: a run to Leicester, under 5 miles away, or any distance on the M1, under a mile from Ratby, where the motor kept labouring hard. Driven until it protested. Clattering, an uneven idle, smoke, a throttle that has gone soft. The fuel is not acting like diesel any more, and the engine is telling you. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Berry's Lane. The drain and flush-through still go first, and they take care of it: when a car is pulled over soon, permanent damage is very uncommon. ## What Ratby people get told about petrol in a diesel — and the myths in it Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing comes out when you top up — the tank just holds more of the same blend. That guidance supposes a diesel fuel system tolerates petrol by percentage. It doesn't. Myth: a newer diesel copes with a bit of petrol. If anything, the opposite. Protection matters more on current diesels, not less, because their fuel passes through finer parts at higher pressure. Myth: "If it starts and drives, there is no harm done." This is the one that catches motorists. Feed diesel to a petrol engine and it usually won't run, and so the motorist stops — and the harm stops with them. A diesel fed petrol usually starts, ticks over and drives away as though nothing has happened, while your pump wears. Running doesn't mean fine. An outdated workaround for a distinct issue is behind this one. Myth: "Add some two-stroke oil and drive the car home." What petrol has thinned remains thinned, and that petrol stays in that tank regardless. The next start draws petrol back round your pump out of the lines and your filter, where some of it sits after the engine has been run. That's why a DIY tank drain doesn't sort it — a myth. Emptying petrol into a can by the kerbside is also genuinely risky. ## How does petrol in a diesel take place? It's seldom carelessness, and no one does it on purpose. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol motor at all. The forecourt makes it easy, and the slip runs one way. When routine and the vehicle stop matching, it takes place. A new motor, a hire car or a courtesy car. Households running one of each, petrol and diesel. Your usual forecourt, its pumps suddenly in a different order. Filling up in a hurry on the way to Leicester, with a train to catch. Years of petrol motors behind you, a diesel Renault Clio in front of you on the forecourt for its first tank — that's when. With rain, a call arriving, or children to deal with, your hand just does what it always has. ## Next time you fill up in Ratby: avoiding petrol in a diesel - Green for unleaded and black for diesel is normal in the UK — but not on each forecourt. Go by the label on the petrol pump, not the colour. - Plenty of vehicles state the fuel inside your filler flap or on the cap, so check there on your first fill in any motor you do not know. - Good intentions do less than a sticker or a fob in a bright colour on the diesel's key when a household has one of each. So mark it. - Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It sounds silly and it does the trick. - Mistakes like this are simple to make while your mind is on something else, and so your phone goes away. - A misfuel inhibitor helps, up to a point. Some diesels have a filler built to reject a petrol nozzle, and add-on devices are available for cars without one. They are a backstop, not a reason to stop reading the pump. - The moment you notice, stop: less petrol inside your tank makes a weaker mix. What to do next does not change, though — still do not fire it up. ## Petrol already in a diesel around Ratby? Start here In that case, there is only a short order of things. Never fire it up, and don't turn your ignition on. Ask the staff to help you roll it away from the pump if you are still on the forecourt, whether that's Morrisons or anywhere else. Then call 0333 366 0103 and tell us what went in, roughly how much, and whether it's run. Say so if it was AdBlue rather than petrol: it's a separate problem, with its own page for Ratby, because AdBlue brings corrosion and deposits rather than lost protection. ## One petrol in a diesel task around Ratby costs more than another. Why? An honest single quote does not exist here: four situations, four separate tasks. Mostly, the cost shifts with which situation you're in. After that it's the share — how much petrol was put in against how much your tank holds — and after that where the car is and whether our van can reach it safely. Before any quote, not after, come three questions: your fuel that got in, the volume, and whether it has run. That's why. A range becomes a straight figure when the answers are in. ## About Ratby itself Ratby is a village in Leicestershire, situated on the River Soar, with a mix of semi-detached housing and other residential properties. Ratby sits at an elevation of around 94 metres, close to the nearby villages of Kirby Muxloe and Groby. Ratby is located near the city of Leicester, approximately 4.8 miles to the west, and is part of the wider East Midlands region. Ratby has a population of around 1524 people, living in a variety of housing types, predominantly semi-detached homes. ## Ratby and Leicestershire: where our fuel drain cover reaches Ratby sits in the LE postcode area, and our teams that answer petrol in diesel jobs there work the spots near it as well — Kirby Muxloe, Groby and Bondman Hays among them. Our technicians drain where your vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us. ## At the petrol pump around Ratby, right now? Then, you could not be in a better spot. Ring, and keep it turned off.