--- title: Petrol in a Diesel Car Wick — Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/wick-the-vale-of-glamorgan/ location: Wick county: The Vale of Glamorgan latitude: 51.437940 longitude: -3.551060 service: Petrol in a Diesel Car updated: 2026-10-18 --- # How Worried Should You Be? Petrol in a Diesel Car in Wick Less than you likely are, if it hasn't been started. "Have I wrecked it?" is the first thing everyone around Wick asks, and the truthful answer is usually no, since petrol left in a diesel tank harms nothing till it's drawn through your fuel system — by ignition priming, by the starter, or by driving. Leave your engine off and call Petrol in Diesel — that keeps it like that. Further down, you will find what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you again. ## Petrol in a diesel: what does it do to your engine? On its way through a motor, diesel has two jobs. It protects first, and only then does it burn. What keeps the surfaces inside the high-pressure pump and the fuel injectors from grinding against each other is the diesel passing through them — they're built to extremely fine tolerances. The second job petrol doesn't do at all, and the first it does badly. A pump running on a petrol blend is wearing itself out, since petrol is thinner than diesel and takes away 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 the rattling comes. Put these together and the shape of the issue is clear. Contact doesn't do the damage — movement does. Petrol in a tank is a fuel fault. The beginning of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with your fuel to the fuel injectors beyond it. ## Petrol in a diesel around Wick: how serious is it? Four situations Filled but never started — the best it gets. On a forecourt, and genuinely only there, the petrol is still confined to that tank — since anywhere else the vehicle was driven to reach it. The job is emptying and flushing on the spot. The ignition turned on, or a short start. With the fuel system primed, the fuel lines and filter now hold petrol that has come from your tank. Still normally easy: drain, flush, and the filter seen to. Driven a few miles. Now your pump has spent these miles labouring on thinned fuel. How hard the vehicle was driven counts as much as how far, and the work covers the tank, the lines, the filter and clean fuel through the entire circuit. The school run to the local primary school is one thing. Any miles on the M4, under 10 miles from Wick, means the engine working hard throughout, and a run to Cardiff, under 25 miles away, is a very different job too. Driven until it protested. Knocking, a ragged idle, smoke, a throttle that has gone soft. What you are hearing is the engine reporting fuel that no longer runs like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Church Road. A vehicle pulled over soon very seldom has lasting damage, as the fuel drain and the flush-through, which still go first, sort it out. ## Myths Wick people hear about petrol in a diesel Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing comes out when you top up — the tank simply holds more of the same mixture. A diesel fuel system does not tolerate petrol by percentage in the way that guidance presumes. Not so: a current diesel copes with a bit of petrol. Rather, the opposite. Lubrication counts more on current diesels, not less, because their fuel runs through more precise parts at higher pressure. Myth: "If it starts and drives, there's no harm done." This is the one that fools people. The motorist of a petrol engine fed diesel usually has no choice but to stop, because it will not run, and the damage stops with them. While the pump grinds, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Fine and running aren't the same at all. Myth: "Add some two-stroke oil and drive it home." It is an outdated workaround for a separate problem. None of what petrol thinned is put back by it — and afterwards, that tank still holds that petrol. The next start sends petrol back round your pump from the lines and your filter, where some of that sits once the motor has run. That is why a DIY tank drain doesn't sort it — a myth. Emptying petrol into a can by the roadside is also genuinely hazardous. ## Petrol in a diesel: how does it occur? No one does it on purpose, and it is seldom carelessness. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol motor at all. The forecourt makes it easy, and the slip runs one way. When habit and the vehicle stop matching, it takes place. Courtesy car, hire car, or a motor that is new. A household with one petrol and one diesel on the drive. A forecourt you know, only with its pumps laid out differently. A train to catch, and a rushed fill on the way to Llantwit Major. Precisely the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. 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 Wick: preventing petrol in a diesel - Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on every forecourt. The label is what matters. - In a car you do not know, look inside the flap over your filler or at the cap before your first fill: many vehicles state the fuel type there. - A coloured fob or a sticker on the diesel's key does more than any amount of intending to remember, in a household with one of each. - Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It seems daft and it works. - Whilst you are thinking about something else, this is an easy mistake to make — so tuck your phone away. - A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to refuse a petrol nozzle, and add-on devices exist for motors without one. They are a safety net, not a reason to stop checking the pump. - Stop as soon as you realise. Less petrol inside that tank makes a weaker blend. It doesn't change what to do next, which is still not to crank it. ## Put petrol in a diesel around Wick already? Short and simple, then, is the order of things. Do not turn your ignition on, and don't start it. The staff at the forecourt — whether at BP itself or wherever you filled up — will normally help roll it away from the petrol pump if you ask. What got in, roughly how much, and whether it's run: tell us those when you ring 0333 366 0103. Corrosion and deposits form the trouble with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and see its own Wick page. ## One petrol in a diesel job in Wick costs more than another. Why? An honest single price does not exist here: four situations, four separate jobs. What moves your cost is chiefly which of them you are in. The ratio matters next, meaning how much of that tank is petrol, and then the position of the vehicle and whether reaching it is safe for a van. What went in, how much, and whether it has run — three queries we ask before pricing, not after, for exactly that reason. Given those replies, you get a straight figure instead of a range. ## About Wick and its setting Wick is a small coastal village in the Vale of Glamorgan, situated near the towns of Llantwit Major and Cowbridge. Wick sits at an elevation of around 90 metres, overlooking the Bristol Channel, and is characterised by its predominantly detached housing stock. Wick is located near several other small villages, including Tre-pit, Broughton, and Monknash, and is within commuting distance of Cardiff, the capital city of Wales. ## Wick and The Vale of Glamorgan: where our fuel drain cover runs The teams answering petrol in diesel call-outs in Wick, in the CF postcode area, also work the places around it, Tre-pit, Broughton and Monknash among them. The vehicle doesn't need to move to us: we drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway. ## In Wick and still at the pump? In that case, you could not be in a better position. Keep the vehicle switched off, then ring.