--- title: Barnhill: Petrol in a Diesel Car, Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/barnhill-dundee-city/ location: Barnhill county: Dundee City latitude: 56.474690 longitude: -2.857510 service: Petrol in a Diesel Car updated: 2026-10-04 --- # Petrol in a Diesel Car in Barnhill: How Worried Should You Be? Less than you probably are, if it has not been started. Everyone in Barnhill begins with "have I wrecked it?", and the honest answer is usually no: petrol left inside that tank of a diesel stays harmless till priming, cranking or driving draws it into the system. Petrol in Diesel is who to ring, with the motor kept off, so it remains that way. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has got, and the way to make sure you don't do it again. ## What petrol in a diesel does to the motor Two jobs fall to diesel on its journey through a motor. Oiling comes before burning; it does both. Your high-pressure pump and your injectors are made to extremely fine tolerances, and the diesel passing through them is what keeps those surfaces from grinding against each other. Of those two jobs, petrol handles the first poorly and the second never. A pump running on a petrol mix is wearing itself out, because petrol is runnier than diesel and strips out the protection the fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where any rattling comes. The shape of the problem is plain once you put those together. Not contact but movement is what does the damage. All a tank with petrol in it amounts to is a fuel problem. A pump that has been labouring on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with the fuel to the fuel injectors downstream. ## How serious is petrol in a diesel? Four situations our technicians see around Barnhill Filled up, never started. The best case there is. That petrol is in that tank and only that tank, and the task is a drain and a flush where your car sits. This is the one scenario that can only really occur on a forecourt, since anywhere else the car has been driven to get there. Started for a moment, or only the ignition on. With the fuel system primed, the lines and filter already contain petrol that has come from that tank. Still usually simple: drain, flush, and your filter sorted. Those few miles on the road were the pump running on fuel weakened by petrol throughout. Tank, lines, filter, then fresh fuel put through the whole circuit: that is the work, and the way the vehicle was driven counts as much as the distance. On the school run to the local primary school, the mileage is short. A run as far as Dundee, under 5 miles away, is a very different task. So is any mileage on the M90, under 25 miles from Barnhill, where your engine has been labouring hard the whole time. Rattling, a lumpy idle, smoke, a throttle gone soft: driven until it complained. 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 Edzell Street. What comes first is still the drain and flush-through, and that sorts it out, with permanent damage very uncommon when a car is pulled over soon. ## Myths Barnhill drivers hear about petrol in a diesel Myth: topping up to full with diesel makes it fine. It doesn't. Topping up takes out nothing; it gives you a bigger tank of the same mix. Percentage isn't how a diesel fuel system copes with petrol, however much that advice assumes. Not so: a current diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through more precise components: that is how a current diesel handles its fuel, so the protection matters more, not less. The myth that catches drivers off guard: if it starts and drives, it must be unharmed. A petrol motor fed diesel normally will not run, so the motorist stops and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile the pump grinds. Running does not mean fine. An old fix for a separate issue is behind this one. Myth: "Add some two-stroke oil and drive it home." The petrol is still in the tank afterwards, and what it has thinned isn't put back. The next start sends petrol back round the pump from the fuel lines and the fuel filter, where some of it sits after the engine has been run. That's why draining the tank yourself doesn't sort it — a myth. Also, a can of petrol filled at the roadside is genuinely hazardous. ## Why petrol in a diesel takes place at all Nobody does it on purpose, and it is rarely carelessness. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one mostly will not fit a petrol motor. That is how the forecourt makes it easy. Routine and the vehicle getting out of step is how it happens. A vehicle that is new to you — hired, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. Your usual forecourt, its pumps suddenly in a different order. A train to catch, and a rushed fill en route to Balmossie. A new-to-you diesel Renault Megane, its first fuelling, and a driver used to petrol: precisely when it takes place. The hand does what it has always done when you add rain, a phone call or a back seat full of children. ## Preventing petrol in a diesel next time you fill up around Barnhill - Check the pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on each forecourt. The label is what counts. - In a car you don't know, look inside the flap over the filler or at the cap before the first fill: many motors state the fuel type there. - One of each in the home? Label the key to your diesel — a bright fob, a sticker — since intending to remember is not enough. - It sounds silly and it works: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump. - Put your phone away. This is an easy mistake to make whilst you are thinking about something else. - Some diesels come with a filler built to refuse a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump. - The moment you notice, stop: less petrol in that tank makes a weaker blend. What to do next doesn't change, though — still do not crank it. ## Put petrol in a diesel around Barnhill already? Short and simple, then, is the order of things. Leave it unstarted, with the ignition switched off too. Yet on the forecourt, at Esso or anywhere else? Ask the staff to help you roll the car away from the pump. What got in, roughly how much, and whether it has run: tell us that when you call 0333 366 0103. Corrosion and deposits are the problem with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and see its own Barnhill page. ## One petrol in a diesel job around Barnhill costs more than another. Why? The four scenarios above are four separate tasks, so no single price for this would be honest. Mostly, the cost shifts with which situation you are in. Two things come after that: the petrol that was put in as a proportion of what your tank takes, then the place the vehicle is in and whether our van can reach it safely. Three queries come first, before quoting, instead of after — what got in, how much, has it run — and this is the reason. With the replies, you get a straight figure rather than a range. ## About Barnhill, briefly Barnhill is a suburban area located on the coast of Dundee City, sitting at an elevation of 38 metres and approximately 4.6 miles from Dundee city centre. Barnhill is characterized by its semi-detached housing and is situated near other nearby places such as Broughty Ferry and West Ferry. Barnhill has a population of around 4960 residents and is part of the larger Dundee urban area. Barnhill's coastal setting provides scenic views and a unique environment for its residents. ## Fuel drain cover across Dundee City, Barnhill included Barnhill sits in the DD postcode area, and the vans that answer petrol in diesel call-outs there work the locations near it as well — Broughty Ferry, Balmossie and West Ferry among them. Our engineers drain where your vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us. ## At the pump in Barnhill, still? In that case, you could not be in a better position. Phone, and leave it switched off.