--- title: Explained: Petrol in a Diesel Car Drylaw canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/drylaw-city-of-edinburgh/ location: Drylaw county: City of Edinburgh latitude: 55.964030 longitude: -3.248680 service: Petrol in a Diesel Car updated: 2026-10-05 --- # Should You Worry? Petrol in a Diesel Car in Drylaw Less than you probably are, if it has not been started. Till the ignition primes your pump, your starter cranks, or the vehicle is driven, petrol in a diesel tank simply waits there and does nothing. Which makes the truthful reply to that first Drylaw question — "have I wrecked it?" — normally no. Petrol in Diesel is who to ring, with your motor kept off, so it stays that way. Read on for three things: the effect petrol has inside a diesel motor, the clues of how far it has spread, and ways to make sure you never do it again. ## Your engine and petrol in a diesel: what happens Two tasks fall to diesel on its route round a motor. Lubricating comes before burning; it does both. Made to extremely fine clearances, the fuel injectors and the pump depend on the 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 badly. A pump working on a petrol mixture is wearing itself out, since petrol is runnier than diesel and takes away the protection your fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where the clattering starts. Together, those make the shape of the issue plain. Contact doesn't do the harm — circulation does. Any tank with petrol in it is a fuel problem. Whatever a worn pump sheds goes on, borne by the fuel, into the fuel injectors further along, which is why a pump that has been working on that petrol is where a mechanical issue begins. ## Petrol in a diesel in Drylaw: how bad is it? Four cases Fuelled up, never started. The best case there is. Only your tank has petrol in it, and so the task is emptying the tank and cleaning the system where the car sits. This situation can only really happen on a forecourt: anywhere else, your car got there by being driven. Ignition on, or started for a moment. With your system primed, the lines and filter already hold petrol that came from the tank. Drain, flush, deal with the fuel filter: still usually easy. A couple of miles driven, and your pump has spent each of them labouring on weakened fuel. Distance is only half of it; how hard it was driven matters just as much. Either way this work includes your tank, your lines, your filter and fresh fuel through the entire system. Driving the children to the local primary school is one kind of trip. Any mileage on the M8, under 5 miles from Drylaw, means the engine has worked hard throughout, and a run to Edinburgh, under 3 miles away, is a very different task as well. Driven on till it complained — clattering, smoke, an uneven idle, a dead throttle. What you are hearing is your motor signalling fuel that no longer behaves like diesel. Stop wherever you are — the verge on Easter Drylaw Avenue, a lay-by, a side street — and leave the car where it is. What comes first is still the drain and flush, and that takes care of it, with permanent damage very uncommon if a vehicle is stopped early. ## Petrol in a diesel myths Drylaw motorists hear It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Topping up takes out nothing; it gives you a fuller tank of the same mixture. The idea behind the advice — that diesel fuel systems accept petrol by percentage — is wrong. Myth: a modern diesel copes with a bit of petrol. Rather, the opposite. A newer diesel sends its fuel through finer parts at higher pressure, which makes the lubrication count more, not less. "It starts, it drives, and so there is no harm" — the myth that catches most people than any other. The motorist of a petrol engine fed diesel usually has no choice but to stop, because it will not run, and the damage stops there. A diesel fed petrol usually starts, idles and drives away as though nothing has happened, whilst the pump wears. Running doesn't mean fine. An old fix for a separate problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol diluted gets put back by it — and later, that tank still holds the petrol. If the engine has been run, part of that petrol is in your filter and the fuel lines, not the tank — and the next start pulls it right back through the pump. So the myth "drain that tank yourself and you are sorted" does not hold. Emptying petrol into a can by the kerbside is also genuinely risky. ## Petrol in a diesel: how does it occur? Carelessness is seldom the cause, and nobody means to do it. A diesel nozzle mostly won't go into a petrol motor, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in that direction. It happens when routine and the car stop matching. A vehicle that's new to you — hired, on loan as a courtesy car, or brand new. One petrol and one diesel on the drive of the same household. A familiar forecourt with the pumps in a different order. A hurried fill on the way to Haymarket with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is precisely the moment it occurs. Add rain, a phone call or a back seat full of children, and the hand does what it has always done. ## Next time you fill up in Drylaw: avoiding petrol in a diesel - The label is what matters, so read the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt. - The first fill in a strange motor is the time to check the filler flap — on it, or on the cap, many vehicles state the fuel to use. - Good intentions count for less than a sticker or a fob in a vivid colour on your diesel's key if a home has one of each. So label it. - It sounds silly and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. - Mistakes like this are straightforward to make while your mind is on something else, so your phone goes away. - A misfuel inhibitor helps, up to a point. Some diesels have a filler built to block a petrol nozzle, and add-on devices are available for cars without one. They are a backstop, not a reason to stop reading the petrol pump. - The moment you notice, stop: less petrol in your tank makes a thinner mixture. What to do next does not change, though — still do not start the car. ## Put petrol in a diesel in Drylaw already? The order of things is brief, then. Starting it is out, and so is turning on your ignition. Yet at the forecourt, at Sainsbury's or anywhere else? Ask the staff to help you push the vehicle away from the pump. Next, 0333 366 0103. We'll ask what went in, roughly how much, and if it's been run. If it was AdBlue and not petrol, say so. That's a different problem — corrosion and deposits instead of lost protection — and it has its own page for Drylaw. ## One petrol in a diesel job in Drylaw costs more than another. Why? There is no fair single price for this, because the four scenarios above are four different tasks. Chiefly, your cost moves with which one you are in. The share matters next, meaning how much of your tank is petrol, and then the position of the vehicle and whether getting to it is safe for a technician. What went in, how much, and if it's run — three queries our engineers ask before pricing, not after, for exactly that reason. A range turns into a straight figure once those replies are in. ## About Drylaw and its setting Drylaw is a suburban area in the City of Edinburgh, situated approximately 2.4 miles northwest of Edinburgh's city centre. Drylaw occupies a coastal setting, with its elevation at around 56 metres above sea level, and is characterised by predominantly flat-type housing. Drylaw is close to nearby places such as Blackhall, Craigleith, and West Pilton, and is home to a population of around 8316 people. ## Fuel drain cover in Drylaw and across City of Edinburgh Petrol in diesel jobs in Drylaw — part of the EH postcode area — go to teams that also cover the locations round it, Blackhall, Craigleith and West Pilton among them. A forecourt, a supermarket car park, a lay-by or your own drive are all places our engineers drain, and your car doesn't need to come to us. ## At the pump in Drylaw, right now? Then you are in the best spot there can be. Leave the car switched off, then ring.