--- title: Benhall: Petrol in a Diesel Car, Explained canonical: https://www.petrolinadieselcar.co.uk/petrol-in-diesel/benhall-gloucestershire/ location: Benhall county: Gloucestershire latitude: 51.895650 longitude: -2.124220 service: Petrol in a Diesel Car updated: 2026-10-05 --- # Benhall: Petrol in a Diesel Car? How Worried to Be Less than you probably are, if it has not been started. Until the ignition primes the pump, the starter turns, or the vehicle is driven, petrol in a diesel tank just sits there and does no harm. Which means the truthful reply to that first Benhall question — "have I ruined it?" — normally no. To keep the car that way, call Petrol in Diesel then leave your motor switched off. What petrol really does to a diesel, how to gauge how far it has travelled, and how to stop it from happening a second time: that is the remainder of this page. ## Petrol in a diesel: what does it do to the engine? Passing through an engine, diesel is doing two jobs at the same time. Lubricating comes before burning; it does both. Built to very fine clearances, the fuel injectors and your pump rely on your diesel moving through them to stop their surfaces wearing against one another. Petrol does the first task poorly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so a pump running on the mixture to wear itself. It is also made to resist igniting under compression — the opposite of what a diesel needs — which is why you get the clattering. Put those together and the shape of the issue is clear. The harm is done by movement, not by contact. Petrol in a tank is a fuel fault. Once the pump has been working on that petrol, a mechanical issue has started: anything shed by a pump that's wearing down travels onward to the fuel injectors with the fuel. ## Petrol in a diesel in Benhall: how bad is it? Four situations Fuelled but not once started — the best it gets. That petrol is inside your tank and only the tank, and the task is a drain and a flush where the vehicle sits. This is the one scenario that can only really happen at a forecourt, since anywhere else your car has been driven to get there. The ignition switched on, or a short start. With the fuel system primed, your lines and filter now contain petrol that has come from the tank. Still usually easy: drain, flush, and the filter seen to. The pump has worked a couple of miles on thinned fuel — that is what driving the vehicle meant. The work is the tank, the lines, the fuel filter and fresh fuel through the whole system, and how hard the vehicle was driven matters as much as how far. A school run to St Mark's Church of England Junior School is one matter. A run as far as Gloucester, under 10 miles away, is a very different task. So is any miles on the M5, under 3 miles from Benhall, where the motor has been working hard the whole time. Driven till it complained. Rattling, a lumpy idle, smoke, a throttle that has gone soft. What you are hearing is the engine signalling fuel that no longer behaves like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Gloucester Road. The drain and flush-through still go first, and they take care of it: if a car is stopped early, lasting damage is very uncommon. ## Petrol in a diesel myths Benhall people hear Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing comes out when you top up — the tank just holds more of the same blend. Percentage is not how a diesel fuel system copes with petrol, however much that advice presumes. If anything, the opposite is true. Myth: "A current diesel can cope with a bit of petrol." A current diesel sends its fuel through finer parts at higher pressure, which makes the protection matter more, not less. Myth: "If it starts and drives, there's no damage done." This is the one that fools drivers. A petrol engine fed diesel normally will not run, and so the motorist stops and the harm stops with them. A diesel fed petrol generally starts, idles and drives away as though nothing has happened, whilst the pump wears. Being able to run is not the same as being fine. Not so: a two-stroke additive lets you to drive home. It is an old fix, meant for another problem. It doesn't put back what petrol has thinned, and that petrol is still in the tank after that. Myth: "Drain your tank yourself and you're sorted." Once the motor has run, some of the petrol is no longer in the tank: it is in your filter and the lines, and it goes right back through the pump on your next start. Besides, petrol drained into a can by the road is truly risky. ## Why petrol in a diesel takes place so easily It's rarely carelessness, and no one does it on purpose. The forecourt makes it simple: the petrol nozzle is the slimmer of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle generally will not go into a petrol motor at all. So the error runs one way. It occurs when habit and the vehicle stop matching. Any car that is new to you — hired, on loan as a courtesy car, or brand new. Two cars on one drive, one petrol, one diesel. Your usual forecourt, its pumps now in a different order. Fuelling up in a hurry on the way to Cheltenham Spa, with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is precisely the moment it takes place. Add rain, a phone call or a back seat full of kids, and your hand does what it has always done. ## Benhall motorists: how to avoid petrol in a diesel next time - Green for unleaded and black for diesel is normal in the UK — but not on every forecourt. Go by the label on the petrol pump, not the colour. - Check your filler flap. Plenty of cars state the fuel inside the flap or on the cap. Look at it on your first fill in a motor you don't know. - Label 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 meaning to remember. - "Diesel", out loud, before you pick up the nozzle — every time a new or hired car needs its first tank. It seems silly. It does the trick. - Mistakes like this are easy to make whilst your mind is on something else, and so your phone goes away. - A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to reject a petrol nozzle, and add-on devices are available for cars without one. They are a backstop, not a reason to stop checking the petrol pump. - Less petrol means a weaker blend, so stop the moment you realise — while remembering that your next step is unchanged. It is still not to crank it. ## Put petrol in a diesel in Benhall already? In that case, there is just a short order of things. Starting it is out, and so is turning on the ignition. If you are still on the forecourt — Asda or anywhere else — ask the staff to help you roll the vehicle clear of the pump. Call 0333 366 0103 next, with three answers — the fuel, the approximate volume, and if it has run. Say so if it was AdBlue instead of petrol: it's a separate problem, with its own page for Benhall, because AdBlue brings corrosion and deposits instead of lost protection. ## Why one petrol in a diesel task around Benhall costs more than another There's no fair single quote for this, since the four situations above are four separate tasks. Which of them you are in is mostly what shifts the cost. Beyond that it is the share — how much petrol got in against how much the tank holds — and after that where the car is and whether our van can reach it safely. What was put in, how much, and whether it's run — three questions our technicians ask before quoting, not after, for precisely that reason. With the answers, you get a straight figure rather than a range. ## About Benhall, for a moment Benhall is a suburban area in Gloucestershire, situated near the River Severn at an elevation of 44 metres. Benhall lies on the outskirts of Gloucester, approximately 5.7 miles from the city centre, and is surrounded by nearby places such as Fiddlers Green and St Marks. Benhall has a population of around 4609 people, predominantly living in semi-detached housing. Benhall is also relatively close to London, being about 89.6 miles away. ## Fuel drain cover across Gloucestershire, Benhall included Fiddlers Green, St Marks and The Reddings are among the locations near Benhall that the same vans work, answering petrol in diesel call-outs across Benhall's GL postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians work, and your car does not need to come to us. ## In Benhall and still at the pump? No position is better: that's where you now are. Keep it switched off, then ring.