--- title: Explained: Petrol in a Diesel Car Tone canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/tone-somerset/ location: Tone county: Somerset latitude: 50.988810 longitude: -3.245830 service: Petrol in a Diesel Car updated: 2026-10-01 --- # Tone: Petrol in a Diesel Car? How Worried to Be Likely less than you already are — as long as no one has started it. Petrol resting in a diesel tank does nothing to your motor till something draws it through the system — your ignition priming the pump, the starter, or driving itself. So the honest answer to the first question anyone around Tone asks, "have I wrecked it?", is generally no. Keep it like that: leave the motor off then call Petrol in Diesel. What petrol really does to a diesel, how to judge how far it has travelled, and how to stop it from happening again: that is the rest of this page. ## What petrol in a diesel does to the engine On its way through an engine, diesel has two jobs. It burns, and before it burns it protects. Your high-pressure pump and the fuel injectors are made to extremely fine gaps, and the diesel passing through them is what stops those surfaces from wearing down 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, since petrol is runnier than diesel and strips out the protection your fuel system depends 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 clattering starts. Seen together, they show what shape the issue takes. Contact does not do the harm — movement does. All a tank with petrol in it amounts to is a fuel issue. Once the pump has been labouring on that petrol, a mechanical issue has begun: whatever is shed by a pump that's wearing is carried downstream to the fuel injectors with your fuel. ## Four scenarios our engineers see around Tone: how bad is petrol in a diesel? The best case there is: filled up, not once started. On a forecourt, and genuinely only there, the petrol is still confined to that tank — since everywhere else your car was driven to reach it. The task is emptying and purging on the spot. Ignition on, or started for a second. Your system has been bled, so petrol has left the tank and reached your filter and your lines. Still normally simple: drain, flush, and the filter dealt with. A couple of miles driven, and your pump has spent every one of them labouring on weakened fuel. How hard your car was driven counts as much as how far, and the work takes in the tank, the lines, the fuel filter and fresh fuel through the whole system. Short trips, such as the school run to Rockwell Green Church of England Primary School, are one matter. Any mileage on the M5, under 3 miles from Tone, means the engine has worked hard throughout, and a run to Exeter, under 25 miles away, is a very different task as well. Driven on until it complained — knocking, smoke, a lumpy idle, a dead throttle. What you are hearing is your engine signalling fuel that no longer behaves like diesel. Whether it's the verge on Thomas Fox Road, a lay-by or a side road, stop there and leave it. Long-term damage is very uncommon when a car is pulled over soon, and the drain and flush that still go first sort it out. ## What Tone people get told about petrol in a diesel — and the myths in it "Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Topping up takes out nothing; it gives you a bigger tank of the same mixture. A diesel fuel system doesn't accept petrol by percentage in the way that advice supposes. "Current diesels can handle a little petrol" — a myth, and closer to the reverse. At higher pressure, through smaller parts: that's how a newer diesel handles its fuel, and so the lubrication matters more, not less. The myth that catches people out: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel usually stops, since it will not run, and the damage stops with them. While the pump wears, a diesel fed petrol normally starts, ticks over and drives away as though nothing has happened. Running isn't the same as fine. Myth: "Add some two-stroke oil and drive the vehicle home." It's an old fix for a different problem. The petrol is still in your tank after that, and what it has weakened is not put back. The next start sends petrol back round the pump out of the fuel lines and your filter, where some of that sits after the engine has run. That is why a DIY tank drain doesn't sort it — a myth. Draining petrol into a can by the kerbside is also truly risky. ## How petrol ends up: petrol in a diesel On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle generally will not fit a petrol motor, yet the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and just in one direction. Routine and the vehicle falling out of step is when it occurs. Courtesy car, hire car, or a vehicle that's brand new. Two vehicles on one drive, one petrol, one diesel. The pumps in a different order on a familiar forecourt. A hurried fill on the way to Taunton with a train to catch. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. With rain, a call coming in, or children to deal with, the hand just does what it has always done. ## Tone people: how to avoid petrol in a diesel next time - Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Check the pump's label; the colour is only a hint. - Many cars state the fuel type inside the filler flap or on the cap, and so check it on your first fill in any motor you do not know. - A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, for a home 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. - While you're thinking about something else, this is an easy mistake to make — so tuck the phone away. - Add-on devices exist for motors without one, and some diesels are built with a filler that won't take a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label. - Spotting it halfway? Stop there and then. A thinner mix results from less petrol inside that tank, yet your next stage stays the same: don't crank it. ## Put petrol in a diesel around Tone already? Then, there's just a short order of things. Do not turn your ignition on, and don't fire it up. If you're still on the forecourt — BP or anywhere else — ask the attendants to help you roll it clear of the pump. Ring 0333 366 0103 next, with three facts — your fuel, the approximate quantity, and whether it has run. Corrosion and deposits are the issue with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and read its own Tone page. ## What makes one Tone petrol in a diesel job cost more than the next There is no fair single quote for this, because the four scenarios above are four separate tasks. Which of them you're in is chiefly what moves your cost. Two things follow that: the petrol that went in as a share of what your tank takes, then the place your car is in and whether a technician can get to it safely. What was put in, how much, and whether it has run — three questions our technicians ask before costing, not after, for exactly that reason. The answers turn a range into a straight figure. ## About Tone and where it is Tone is a suburban area in Somerset, situated on the riverside at a relatively low elevation of around 50 metres. Tone lies near several nearby places, including Tonedale, Gundenham, and Runnington, and is characterized by predominantly semi-detached housing. Tone is located near the city of Exeter, which is approximately 22 miles away, and is also within a reasonable distance of London, at around 139 miles. Tone has a population of around 1335 residents. ## Fuel drain cover across Somerset, Tone included Our teams answering petrol in diesel call-outs in Tone, in the TA postcode area, also work the locations near it, Tonedale, Gundenham and Runnington among them. The car doesn't need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway. ## Still at the petrol pump around Tone? The best spot there is, then — that's where you are. Ring, and leave it turned off.