--- title: Great Somerford: Petrol in a Diesel Car, Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/great-somerford-wiltshire/ location: Great Somerford county: Wiltshire latitude: 51.542820 longitude: -2.054000 service: Petrol in a Diesel Car updated: 2026-10-08 --- # Should You Worry? Petrol in a Diesel Car in Great Somerford Less than you probably are, provided it has not been started. Petrol resting in a diesel tank does nothing to your motor till something pulls it through the system — the ignition priming your pump, your starter, or driving itself. So the honest answer to the first question everyone around Great Somerford asks, "have I ruined it?", is normally no. Petrol in Diesel is who to ring, with the motor left off, and so it remains that way. What petrol actually does to a diesel, how to judge how far it's gone, and how to stop it from happening again: that's the rest of this page. ## The motor and petrol in a diesel: what happens On its way through a motor, diesel does two jobs. Oiling comes before burning; it does both. Very fine tolerances are built into the fuel injectors and the high-pressure pump, and just the diesel running through keeps their surfaces from grinding together. Petrol handles the first job badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump on that mixture wearing itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is why you hear the clattering. The shape of the trouble is plain once you put those together. The harm is done by circulation, not by contact. Where that petrol is only in that tank, it's a fault of fuel, nothing more. The beginning of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to your injectors downstream. ## Petrol in a diesel around Great Somerford: how bad is it? Four cases The best case there can be: filled up, not once started. The petrol is inside your tank and only that tank, and the task is a drain and a flush where the vehicle stands. This is the one scenario that can only really take place on a forecourt, as anywhere else the vehicle has been driven to get there. Started for a second, or just the ignition on. Once primed, your system has pulled petrol out of your tank as far as your filter and your lines. Drain, flush, see to the filter: still usually simple. Some miles driven, and your pump has spent each of them running on weakened fuel. The work is that tank, your lines, the filter and fresh fuel through the entire system, and how hard the car was driven counts as much as how far. A school run to Somerfords' Walter Powell CofE Academy is one matter. Driving as far as Bath, under 25 miles away, makes a very different task — as does any distance on the M4, under 3 miles from Great Somerford, with your engine working hard all the way. Driven until it protested. Clattering, an uneven idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer behaving like diesel. Pull up on the spot — on the verge on West Street, at the kerb, down a side road — and don't move it again. Lasting damage is very uncommon when a car is pulled over early, and the fuel drain and flush-through that still come first sort it out. ## Petrol in a diesel myths Great Somerford motorists hear Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A bigger tank of the same mix is all you get, because topping up removes nothing. That guidance supposes a diesel fuel system tolerates petrol by percentage. It does not. "Modern diesels can handle a little petrol" — a myth, and nearer the reverse. A current diesel sends its fuel through smaller components at higher pressure, which makes the lubrication matter more, not less. This is the one that fools motorists. Myth: "If it starts and drives, there is no harm done." Diesel in a petrol motor generally leaves a motor that will not run: the driver stops, and so does the damage. While your pump wears, a diesel fed petrol normally starts, ticks over and drives away as though nothing has happened. Fine and running are not the same at all. An old fix for a separate issue lies behind this one. Myth: "Add some two-stroke oil and drive the car home." It does not put back what petrol has diluted, and that petrol is still inside that tank later. "Drain it yourself and you're sorted" — a myth, since after it has been running some petrol lies in the filter and lines, ready to go straight back through the pump at the next start. On top of that, petrol emptied into a can by the road is truly risky. ## Why petrol in a diesel takes place so easily On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol vehicle at all. The forecourt makes it easy, and the mistake runs one way. It occurs when routine and the vehicle stop matching. A new car, a hire car or a courtesy car. One petrol and one diesel on the drive of the same household. Your usual forecourt, its pumps suddenly in a different order. A rushed fill en route to Chippenham with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a motorist used to petrol: exactly when it happens. Add a back seat full of children, a phone call or rain, and the hand takes over. ## Preventing petrol in a diesel next time you fill up in Great Somerford - Read the 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 motor you don't know, look inside the flap over your filler or at the cap before your first fill: many vehicles print the fuel there. - Mark your key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember. - "Diesel", aloud, before you lift the nozzle — every time a new or hired car needs its first tank. It seems daft. It does the trick. - Tuck your phone away. This is an easy mistake to make whilst you're thinking about something else. - Some diesels have a filler built to refuse a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the petrol pump. - Spotting it halfway? Stop there and then. A thinner mix results from less petrol in the tank, yet the next stage remains the same: don't crank it. ## Petrol already in a diesel in Great Somerford? Begin here Then the order of things is brief. Don't crank it, and do not turn the ignition on. Still on the forecourt, at the nearest petrol station or anywhere else? Ask the attendants to help you roll the car away from the petrol pump. Phone 0333 366 0103 next, with three facts — the fuel, the approximate amount, and whether it's run. AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a different issue — Great Somerford has a page all for it. ## Why one petrol in a diesel task around Great Somerford costs more than another Four different tasks sit behind the four situations above — which is why there is no honest single price. Which of them you're in is mostly what shifts the cost. Next it is the share — how much petrol was put in against how much your tank holds — and after that where the vehicle is and whether our van can reach it safely. That's why our engineers ask three queries before quoting rather than after: what got in, how much, and whether it's run. The replies change a range into a straight figure. ## About Great Somerford and its setting Great Somerford is a village in Wiltshire, situated on the banks of the River Avon at an elevation of 64 metres. Great Somerford lies near the villages of Lower Seagry and Startley, and is close to Seagry Heath. Great Somerford has a population of around 637 people, predominantly living in detached houses, and is located 17.2 miles from the city of Bath. ## Fuel drain cover across Wiltshire, Great Somerford included Our vans answering petrol in diesel calls in Great Somerford, in the SN postcode area, equally work the places near it, Seagry Heath, Lower Seagry and Startley among them. The vehicle does not 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. ## In Great Somerford and still at the petrol pump? The best spot there is, then — that is where you are. Keep it off. Phone.