--- title: Petrol in a Diesel Car Alnwickhill — Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/alnwickhill-city-of-edinburgh/ location: Alnwickhill county: City of Edinburgh latitude: 55.906910 longitude: -3.167130 service: Petrol in a Diesel Car updated: 2026-10-03 --- # Alnwickhill: Petrol in a Diesel Car? How Worried to Be If it has not been started, worry far less than you likely are. Till your ignition primes your pump, the starter cranks, or the vehicle is driven, petrol in a diesel tank simply sits there and does nothing. Which makes the truthful reply to that first Alnwickhill question — "have I wrecked it?" — usually no. To keep it like that, phone Petrol in Diesel and leave your engine switched off. Below, this page sets out what petrol actually does inside a diesel, how far it might have gone, and how to stop it happening to you again. ## What petrol in a diesel does to the motor On its way through a motor, diesel has two tasks. It lubricates first, and after that does it burn. The high-pressure pump and the fuel injectors are made to very fine gaps, and your diesel passing through them is what keeps those surfaces from grinding against each other. Of these two jobs, petrol handles the first poorly and the second not at all. A pump running on a petrol mixture is wearing itself out, since petrol is thinner than diesel and strips out the protection the fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where any rattling starts. Put these together and the shape of the issue is clear. Not contact but movement is what causes the damage. Petrol in a tank is a fuel fault. The beginning of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to the injectors beyond it. ## How serious is petrol in a diesel? Four scenarios we see around Alnwickhill Filled up, not once started. The best case there is. The petrol is inside the tank and only that tank, and the job is a drain and a flush where the car sits. This is the one scenario that can only really occur on a forecourt, as anywhere else the car has been driven to get there. The ignition turned on, or a short start. Petrol has come out of the tank and reached the fuel filter and the lines, since the fuel system has been bled. Normally little more than emptying, cleaning and seeing to your filter, and so still easy. Some miles driven, and your pump has spent every one of them labouring on thinned fuel. The work is the tank, the lines, the fuel filter and clean fuel through the whole system, and how hard the car was driven counts as much as how far. On the school run to the local primary school, the mileage is short. A run as far as Edinburgh, under 5 miles away, is a very different job. So is any mileage on the M8, under 10 miles from Alnwickhill, where the motor has been labouring hard throughout. It protested, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. The engine is telling you your fuel is no longer behaving like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Whiteadder Loan. Permanent damage is very uncommon if a car is pulled over quickly, and the drain and flush that still come first take care of it. ## Petrol in a diesel stories Alnwickhill motorists hear Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up takes out nothing; it gives you a bigger tank of the same mixture. That guidance presumes a diesel fuel system tolerates petrol by percentage. It doesn't. Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. A newer diesel sends its fuel through smaller components at higher pressure, which makes the lubrication matter more, not less. Myth: "If it starts and drives, there is no harm done." This is the one that fools people. Feed diesel to a petrol engine and it normally won't run, and 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, which it usually does; meanwhile your pump wears. Fine and running are not the same thing. An old fix for a separate issue is behind this one. Myth: "Add some two-stroke oil and drive the car home." The petrol is still in your tank after that, and what it has diluted is not put back. The next start sends petrol back round your pump from the fuel lines and the filter, where some of that sits after the engine has been run. That's why draining the tank yourself doesn't sort it — a myth. On top of that, petrol drained into a can by the road is genuinely dangerous. ## Petrol in a diesel: how does it occur? Carelessness is rarely the cause, and no one means to do it. One way only, since of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol car. That is how the forecourt makes it easy. When routine and the vehicle stop matching, it happens. Any car that's new to you — hired, on loan as a courtesy car, or brand new. One petrol and one diesel on the driveway of the same household. A well-known forecourt with the pumps in a different order. A hurried fill en route to Edinburgh Waverley with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is precisely the moment it takes place. Throw in a back seat full of children, a phone call or rain, and the hand wins. ## Preventing petrol in a diesel next time you fill up in Alnwickhill - The label is what matters, so read the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt. - In a motor you don't know, look inside the flap over your filler or at the cap before the first fill: many vehicles state the fuel type there. - One of each in the house? Mark the key to your diesel — a bright fob, a sticker — because intending to remember isn't enough. - It sounds daft and it works: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. - While you're thinking about something else, this is an easy mistake to make — so put your phone away. - Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to reject a petrol nozzle, and add-on devices are available for the rest. Count it as a backstop, then keep checking the pump. - The moment you realise, stop: less petrol in that tank means a weaker mix. What to do next does not change, though — still do not crank it. ## Already put petrol in a diesel around Alnwickhill? In that case, there's just a short order of things. Do not crank it, and do not turn the ignition on. If you're still on the forecourt — Gulf or anywhere else — ask the attendants to help you roll it away from the pump. Then ring 0333 366 0103 and tell us what got in, about how much, and whether it's run. AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different problem — Alnwickhill has a page just for it. ## Alnwickhill petrol in a diesel tasks: why one costs more than another An honest single price does not exist here: four scenarios, four separate jobs. What shifts your cost is mostly which of them you're in. The share counts next, meaning how much of the tank is petrol, and then the position of your car and whether getting to it is safe for a technician. Before any quote, not after, we ask three queries: your fuel that went in, the amount, and if it's run. That's why. Given those answers, there is a straight figure instead of a range. ## About Alnwickhill itself Alnwickhill is a suburban area situated near the River Aln, approximately 3.3 miles from Edinburgh city centre. Alnwickhill sits at an elevation of 129 metres, with the surrounding landscape dominated by the urban sprawl of Edinburgh. Alnwickhill is characterised by its predominantly flat-type housing, which accommodates a population of around 5656 residents. Alnwickhill is close to nearby places such as Kaimes, Southhouse, and Gracemount. ## Across City of Edinburgh and around Alnwickhill: fuel drain cover Petrol in diesel calls around Alnwickhill — part of the EH postcode area — go to teams that also cover the spots around it, Kaimes, Southhouse and Gracemount among them. The car doesn't need to come to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway. ## Still at the pump in Alnwickhill? Then you are in the best place there can be. Keep it off. Ring.