--- title: Petrol in a Diesel Car Greenlaw — Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/greenlaw-scottish-borders/ location: Greenlaw county: Scottish Borders latitude: 55.706760 longitude: -2.461630 service: Petrol in a Diesel Car updated: 2026-10-01 --- # Greenlaw: Petrol in a Diesel Car? How Worried to Be Far less than you probably are, provided it hasn't been started. Until the ignition primes your pump, your starter turns, or your car is driven, petrol in a diesel tank simply waits there and does nothing. Which means the truthful reply to the first Greenlaw query — "have I wrecked it?" — usually no. To leave it like that, phone Petrol in Diesel and leave the engine alone. What petrol actually does to a diesel, how to gauge how far it has gone, and how to stop it from happening again: that's the rest of this page. ## The engine and petrol in a diesel: what happens Two tasks fall to diesel on its route through a motor. It protects first, and after that does it burn. What keeps the surfaces inside the high-pressure pump and the injectors from grinding against one another is the diesel flowing through them — they are built to very fine tolerances. Badly at the first, not at all at the second: that is petrol. The clattering comes from petrol being designed 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 away the lubrication your system depends on, and any pump working on that mixture is wearing itself. Combined, those make the shape of the issue clear. Not contact but circulation is what causes the damage. 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 moves on with your fuel to your injectors further on. ## How bad is petrol in a diesel? Four situations we see around Greenlaw Fuelled, and not started: no case is better. Just that tank has petrol in it, and so the job is emptying that tank and rinsing the fuel system where the car stands. This situation can only truly take place on a forecourt: anywhere else, the car got there by being driven. Your ignition turned on, or a short start. Petrol has left the tank and got to the filter and the lines, because the system has been bled. Normally little more than emptying, rinsing and seeing to the filter, and so still straightforward. Some miles driven, and the pump has spent each of them working on diluted fuel. Tank, lines, filter, then fresh fuel put through the entire circuit: that's the work, and the way your car was driven matters as much as the miles. Short trips, such as the school run to the local primary school, are one thing. Getting as far as Edinburgh, under 50 miles away, makes a very different task — as does any miles on the M8, under 50 miles from Greenlaw, with the engine running hard all the way. Rattling, a ragged idle, smoke, a throttle gone soft: driven until it complained. The engine is telling you your fuel is no longer acting like diesel. Whether it is the verge on Duns Road, a lay-by or a side street, stop there and leave it. What goes first is still the drain and flush-through, and that deals with it, with long-term damage very rare when a vehicle is pulled over quickly. ## Greenlaw motorists and that petrol in a diesel stories they hear False: topping up to full with diesel makes it fine. It does not. Topping up removes nothing; it gives you a fuller tank of the same mix. Percentage isn't how a diesel fuel system copes with petrol, however much that advice presumes. Myth: a modern diesel copes with a bit of petrol. Rather, the reverse. More precise components and higher pressure are how a current diesel runs its fuel, and that makes the protection count more, not less. Myth: "If it starts and drives, there's no damage done." This is the one that fools people. Diesel in a petrol motor normally means a motor that will not run: the driver stops, and so does the damage. While the pump grinds, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. Being able to run is not the same as being fine. An old fix for a distinct issue is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." It does not put back what petrol has diluted, and that petrol is still inside the tank afterwards. "Drain it yourself and you're sorted" — a myth, because after it has been running some petrol sits in your filter and lines, ready to go right back through the pump on your next start. It is also genuinely dangerous to drain petrol into a can at the kerbside. ## Why petrol in a diesel happens at all It is seldom carelessness, and nobody does it on purpose. A diesel nozzle mostly will not go into a petrol vehicle, yet the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and just in that direction. The moment habit stops matching the car is the moment it happens. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. A train to catch, and a rushed fill en route to the nearest station. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver accustomed to petrol: exactly when it occurs. Throw in rain, a phone call or a back seat full of children, and your hand repeats what it has always done. ## How to prevent petrol in a diesel on your next fill-up in Greenlaw - The label is what counts, and so check the pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt. - Check your filler flap. Plenty of vehicles state the fuel inside the flap or on the cap. Look at it on the first fill in a car you don't know. - One of each in the household? Label the key to your diesel — a coloured fob, a sticker — because intending to remember is not enough. - "Diesel", aloud, before you pick up the nozzle — every time a new or hired car needs its first tank. It seems daft. It works. - Mistakes like this are straightforward to make whilst your mind is on something else, so the phone goes away. - Some diesels have a filler built to refuse a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump. - Less petrol means a thinner mixture, so stop as soon as you realise — while remembering that the next stage is unchanged. It's still not to crank it. ## Petrol already in a diesel around Greenlaw? Start here Then, there is only a short order of things. Don't crank it, and do not switch your ignition on. If you are still at the forecourt — the nearest petrol station or anywhere else — ask the attendants to help you roll it away from the pump. What got in, about how much, and if it has run: tell us that when you phone 0333 366 0103. If it was AdBlue instead of petrol, say so. That is a different problem — corrosion and deposits and not lost protection — and it has its own page for Greenlaw. ## Greenlaw petrol in a diesel jobs: why one costs more than another A fair single quote does not exist here: four situations, four separate jobs. The situation itself does most of the work of moving the cost. The ratio counts next, meaning how much of your tank is petrol, and then the position of the car and whether getting to it is safe for a technician. That is why our engineers ask three questions before quoting rather than after: what was put in, how much, and whether it has run. Given those answers, you get a straight figure rather than a range. ## About Greenlaw, for a moment Greenlaw is a village situated on the banks of a river in the Scottish Borders, with a population of around 533 people. Greenlaw has a mix of housing types, but semi-detached homes are particularly prevalent. Greenlaw sits at an elevation of 151 metres, near the communities of Lambden, Hume, and East Gordon. Greenlaw is located approximately 33 miles from Edinburgh, the nearest city. ## Across Scottish Borders and in Greenlaw: fuel drain cover Petrol in diesel calls in Greenlaw — part of the TD postcode area — go to teams that also cover the locations about it, Lambden, Hume and East Gordon among them. Our technicians drain where your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us. ## In Greenlaw and still at the pump? Then you're in the best position there can be. Leave the car switched off, and ring.