--- title: North Coker: Petrol in a Diesel Car, Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/north-coker-somerset/ location: North Coker county: Somerset latitude: 50.915230 longitude: -2.658360 service: Petrol in a Diesel Car updated: 2026-10-28 --- # How Worried Should You Be? Petrol in a Diesel Car in North Coker Far less than you likely are, if it hasn't been started. "Have I wrecked it?" is the first question everyone around North Coker asks, and the honest answer is usually no, because petrol left in a diesel tank hurts nothing till it's drawn through the fuel system — by ignition priming, by the starter, or by being driven. Keep it like that: leave the motor off then phone Petrol in Diesel. Keep reading 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 don't repeat it. ## Inside the engine: what petrol in a diesel really does Two tasks fall to diesel on its journey through a motor. It combusts, and before it burns it protects. Designed to very fine gaps, your injectors and the pump depend on the diesel moving through them to keep their surfaces from wearing against one another. Badly at the first, not at all at the second: that is petrol. A pump running on a petrol mixture is wearing itself out, because petrol is thinner than diesel and takes away the protection the fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that is where the rattling starts. Together, those make the shape of the trouble plain. Contact does not do the damage — movement does. All a tank with petrol in it amounts to is a fuel fault. 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 the injectors further on. ## North Coker, petrol in a diesel: four situations, from mild to serious Fuelled but not once started — as good as it gets. Only your tank has petrol in it, and so the task is clearing your tank and purging the fuel system where the car stands. This scenario can only truly occur at a forecourt: anywhere else, the car got there by being driven. The ignition switched on, or a brief start. With the fuel system primed, the lines and filter now hold petrol that came from your tank. Drain, flush, see to the fuel filter: still normally simple. Those few miles on the road were the pump running on fuel weakened by petrol throughout. Tank, lines, filter, then clean fuel put through the entire system: that's this work, and the way your car was driven counts as much as the distance. Driving the kids to East Coker Community Primary School is one sort of trip. Driving as far as Wells, under 25 miles away, makes a very different job — as does any distance on the M5, under 25 miles from North Coker, with the motor working hard the whole time. Driven on till it complained — rattling, smoke, a lumpy idle, a dead throttle. The fuel isn't behaving like diesel any more, and the motor is telling you. Whether it's the verge on Mill Close, a lay-by or a side road, stop where you are then leave it. What comes first is still the drain and flush, and that takes care of it, with lasting damage very rare if a car is pulled over early. ## What North Coker drivers get told about petrol in a diesel — and the myths in it Myth: topping up to full with diesel makes it fine. It does not. A bigger tank of the same mix is all you get, because topping up takes out nothing. A diesel fuel system doesn't accept petrol by percentage in the way that guidance assumes. Myth: a current diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through more precise parts: that's how a newer diesel moves its fuel, so the protection counts more, not less. This is the one that catches motorists. Myth: "If it starts and drives, there is no harm done." Feed diesel to a petrol motor and it usually will not run, so the driver stops — and the damage stops with them. While the pump grinds, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. Being able to run isn't the same as being fine. An outdated fix for a different issue is behind this one. Myth: "Add some two-stroke oil and drive it home." It does not put back what petrol has thinned, and that petrol is still in that tank afterwards. "Drain it yourself and you're sorted" — a myth, because after it's been running some petrol lies in your filter and lines, ready to go straight back through your pump on the next start. It's also truly dangerous to drain petrol into a can at the kerbside. ## Why petrol in a diesel occurs so easily It is seldom carelessness, and no one does it on purpose. One way only, because of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally will not fit a petrol motor. That is how the forecourt makes it straightforward. Habit and your car falling out of step is how it happens. A new motor, a hire car or a courtesy car. Two vehicles on one driveway, one petrol, one diesel. A forecourt you know, but with its pumps arranged differently. A rushed fill en route to Yeovil Junction with a train to catch. A new-to-you diesel Volkswagen Passat, its first fuelling, and a motorist used to petrol: precisely when it happens. Throw in rain, a phone call or a back seat full of children, and the hand repeats what it has always done. ## Next time you fill up in North Coker: avoiding petrol in a diesel - A green handle for unleaded and black for diesel is usual in the UK — yet not on every forecourt. Trust the label on the pump, not the colour. - In a motor you do not know, look inside the flap over the filler or at the cap before your first fill: plenty of motors print the fuel there. - Mark the key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember. - It seems silly and it works: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump. - Mistakes like this are easy to make while your mind is on something else, and so your phone goes away. - Add-on devices are available for vehicles without one, and some diesels come with a filler that won't accept a petrol nozzle. Useful — but a backstop only, never a reason to stop checking the label. - Less petrol means a thinner mixture, and so stop the moment you realise — while remembering that your next step is unchanged. It is still not to fire it up. ## Put petrol in a diesel in North Coker already? The order of things is brief, then. Leave it unstarted, with your ignition off too. Ask the attendants to help you push it clear of the petrol pump if you are still at the forecourt, whether that is BP or somewhere else. Ring 0333 366 0103 next, with three answers — the fuel, the approximate quantity, and if it has run. If it was AdBlue and not petrol, say so. That's a different problem — corrosion and deposits and not lost lubrication — and it has its own page for North Coker. ## North Coker petrol in a diesel jobs: why one costs more than another There is no fair single price for this, since the four scenarios above are four separate tasks. The situation itself does most of the work of moving your cost. Where your car is counts too, and whether a van can safely reach it, after the share of petrol to what that tank takes. What went in, how much, and if it's run — three queries our technicians ask before costing, not after, for exactly that reason. Those answers are what turn a range into one firm number. ## About North Coker itself North Coker is a village situated in the riverside setting of the River Yeo in Somerset, with an elevation of around 59 metres. North Coker lies near the villages of Burton, East Coker, and Nash, and is approximately 20 miles from the city of Wells. North Coker has a population of around 842 people, predominantly living in detached houses. North Coker is also located within commuting distance to larger cities, with London being around 117 miles away. ## Fuel drain cover across Somerset, North Coker included North Coker sits in the BA postcode area, and the teams that answer petrol in diesel jobs there work the places around it as well — Burton, East Coker and Nash among them. A forecourt, a supermarket car park, a lay-by or your own drive are all locations our technicians drain, and the car doesn't need to come to us. ## Still at the pump around North Coker? Then you're in the best place there can be. Switched off it stays; then phone.