--- title: Worried? Petrol in a Diesel Car Cotgrave canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/cotgrave-nottinghamshire/ location: Cotgrave county: Nottinghamshire latitude: 52.912000 longitude: -1.042560 service: Petrol in a Diesel Car updated: 2026-10-24 --- # Petrol in a Diesel Car in Cotgrave: How Worried Should You Be? Unstarted? Then less anxious than you likely feel. Everyone in Cotgrave begins with "have I wrecked it?", and the fair answer is usually no: petrol left inside your tank of a diesel stays harmless till priming, cranking or driving draws it into the system. To keep it like that, ring Petrol in Diesel and leave the motor alone. Further down, this page sets out what petrol actually does inside a diesel, how far it may have got, and how to stop it happening to you again. ## Petrol in a diesel: what does it do to the motor? Two jobs fall to diesel on its journey through a motor. It lubricates to begin with, and after that does it burn. What keeps the surfaces inside your high-pressure pump and the fuel injectors from wearing against one another is your diesel passing through them — they are built to extremely fine tolerances. Petrol handles the first task poorly and the second not at all. It's runnier than diesel and removes the lubrication the fuel system rests on, so a pump running on a petrol blend is a pump wearing itself. And petrol is made to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the knocking comes from. Put these together and the shape of the trouble is plain. Not contact but circulation is what causes the damage. Where that petrol is only in the tank, it's a problem of fuel, nothing more. A pump that has been labouring on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with the fuel to your injectors further on. ## Four situations our engineers see around Cotgrave: how bad is petrol in a diesel? Filled up, not once started. The best case there can be. Only your tank has petrol in it, so the task is emptying the tank and rinsing your system where the vehicle stands. This situation can only really occur at a forecourt: anywhere else, your car got there by being driven. A brief spell of running, or merely your ignition on. Once primed, the system has pulled petrol from your tank as far as the fuel filter and your lines. That's usually still a simple job — a drain, a flush, and your filter dealt with. Those few miles on the road were your pump working on fuel thinned by petrol throughout. How hard the vehicle was driven matters as much as how far, and this work covers the tank, your lines, your filter and clean fuel through the entire circuit. On the school run to Cotgrave Church of England Primary School, the mileage is short. Any miles on the M1, under 10 miles from Cotgrave, means your engine working hard throughout, and a run to Nottingham, under 10 miles away, is a very different task too. It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone ragged. The fuel is not acting like diesel any more, and the motor is telling you. Leave it wherever it stops: a lay-by, a side street, the verge on Bingham Road. The drain and flush-through still come first, and they take care of it: if a vehicle is stopped soon, lasting damage is very rare. ## Petrol in a diesel stories Cotgrave 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. That advice supposes a diesel fuel system handles petrol by percentage. It does not. Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. Protection counts more on newer diesels, not less, since their fuel passes through more precise components at higher pressure. "It starts, it drives, and so there is no harm" — the myth that catches most drivers than any other. Feed diesel to a petrol motor and it usually won't run, so the driver stops — and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump wears. Fine and running are not the same thing. An outdated workaround for a separate fault lies behind this one. Myth: "Add some two-stroke oil and drive it home." That petrol is still in your tank after that, and whatever it has thinned is not put back. "Drain it yourself and you are sorted" — a myth, because after it's been running some petrol lies in your filter and lines, waiting to go right back through your pump on your next start. It's also genuinely risky to drain petrol into a can by the kerbside. ## How does petrol in a diesel happen? It is rarely carelessness, and no one does it on purpose. The petrol nozzle is the smaller of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol car at all. The forecourt makes it easy, and the error runs one way. Habit and the vehicle getting out of step is when it occurs. Any motor that is new to you — hired, on loan as a courtesy car, or just bought. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps arranged differently. A train to catch, and a rushed fill on the way to Radcliffe (Nottinghamshire). Years of petrol vehicles behind you, a diesel BMW 3 Series in front of you on the forecourt for its first tank — that is when. Add rain, a phone call or a back seat full of kids, and your hand does what it has always done. ## Avoiding petrol in a diesel next time you fill up in Cotgrave - Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Read the petrol pump's label; the colour is only a clue. - Check your filler flap. Many vehicles state the fuel inside the flap or on the cap. Look at it on the first fill in a vehicle you do not know. - A coloured fob or a sticker on your diesel's key achieves more than any amount of meaning to remember, in a household with one of each. - Before the nozzle leaves the petrol pump the first time you fill a hired or new vehicle, say "diesel" aloud. Silly, yes, yet it works. - Mistakes like this are simple to make while your mind is on something else, and so your phone goes away. - Some diesels have a filler built to refuse a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump. - Less petrol makes a thinner blend, so stop as soon as you notice — while remembering that your next step is unchanged. It's still not to crank it. ## Put petrol in a diesel around Cotgrave already? Then, there's just a short order of things. Starting it is out, and so is turning on the ignition. If you're still on the forecourt — JET or anywhere else — ask the attendants to help you roll the car clear of the pump. What got in, about how much, and whether it has run: tell us those when you phone 0333 366 0103. Corrosion and deposits form the issue with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and read its own Cotgrave page. ## Why one petrol in a diesel job around Cotgrave costs more than another The four situations above are four different tasks, so no single quote for this would be honest. Which of them you're in is mostly what shifts your cost. The share matters next, meaning how much of your tank is petrol, followed by the location of the vehicle and whether getting to it is safe for a technician. That's why our technicians ask three questions before costing instead of after: what got in, how much, and whether it has run. Those replies change a range into a straight figure. ## About Cotgrave Cotgrave is a town situated on the banks of the River Trent in Nottinghamshire, with a relatively low elevation of 38 metres. Cotgrave lies approximately 5.5 miles south of Nottingham and 104.5 miles north of London, making it a commuter town for the nearby city. Cotgrave has a mix of housing types, but semi-detached homes are the most predominant. Cotgrave is close to nearby places such as Clipston, Stragglethorpe, and Holme Lane, which are all part of the surrounding landscape. ## Cotgrave and Nottinghamshire: where our fuel drain cover runs The teams answering petrol in diesel call-outs around Cotgrave, in the NG postcode area, equally work the spots around it, Clipston, Stragglethorpe and Holme Lane among them. A forecourt, a supermarket car park, a lay-by or your own drive are all spots our technicians work, and your vehicle does not need to come to us. ## At the petrol pump in Cotgrave, right now? In that case, you couldn't be in a better place. Leave the car switched off, then ring.