Should You Worry? Petrol in a Diesel Car in Highbridge
If it hasn't been started, worry far less than you likely are. Petrol resting in a diesel tank does nothing to the motor till something draws it through the fuel system — your ignition priming your pump, the starter, or the drive itself. So the truthful answer to the first query everyone in Highbridge asks, "have I wrecked it?", is generally no. Keep it like that: leave your engine off then call Petrol in Diesel. What petrol really does to a diesel, how to judge how far it's gone, and how to keep it from happening again: that's the rest of this page.
The motor and petrol in a diesel: what goes on
On its way through an engine, diesel does two jobs. It protects to begin with, and only then does it burn. Very fine gaps go into your injectors and your high-pressure pump, and only the diesel running through stops those surfaces grinding together.
Petrol does the first job poorly and the second not at all. A pump working on a petrol blend is wearing itself out, since petrol is runnier than diesel and takes away the lubrication the fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where any knocking comes.
The shape of the trouble is clear once you put those together. Not contact but circulation is what does the damage. Petrol in a tank is a fuel fault. Whatever a worn pump sheds travels on, carried by your fuel, into the injectors further along, which is why a pump that has been working on the petrol is where a mechanical issue starts.
Petrol in a diesel around Highbridge: how serious is it? Four cases
Fuelled, and never started: nothing beats it. That petrol is in your tank and just the tank, and the job is a drain and a flush where the vehicle sits. This is the one situation that can only really happen on a forecourt, because anywhere else the car has been driven to get there.
Ignition on, or started for a moment. With the fuel system primed, your lines and filter now hold petrol that has come from the tank. Still usually simple: drain, flush, and your filter seen to.
The pump now spent a few miles on diluted fuel — that is what driving it meant. Tank, lines, filter, then clean fuel put through the whole system: that is this work, and the way your car was driven matters as much as the mileage. Short trips, like the school run to Churchfield Church School, are one thing. Any miles on the M5, under a mile from Highbridge, means your engine has worked hard throughout, and a run to Wells, under 15 miles away, is a very different job too.
Clattering, a ragged idle, smoke, a throttle gone soft: driven until it complained. The fuel is not behaving like diesel any more, and the engine is telling you. Whether it's the verge on Grange Avenue, a lay-by or a side road, stop there then leave it. A car pulled over early very rarely has permanent damage, as the drain and the flush, which still go first, take care of it.
What Highbridge drivers get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A bigger tank of the same mixture is all it gives, because topping up removes nothing. The idea behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. More precise components and higher pressure are the way a current diesel runs its fuel, and that makes the protection matter more, not less.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. The motorist of a petrol motor fed diesel normally stops, since it will not run, and the harm stops there. A diesel fed petrol generally starts, idles and drives away as if nothing has happened, while the pump grinds. Fine and running aren't the same thing.
An outdated fix for a different problem is behind this one. Myth: "Add some two-stroke oil and drive it home." It does not put back what petrol has diluted, and the petrol is still inside your tank later on.
Myth: "Drain your tank yourself and you are sorted." Once the engine has been run, some of that petrol is no longer inside the tank: it is in the filter and the lines, and it goes straight back through your pump on your next start. Draining petrol into a can by the kerbside is also really hazardous.
Why petrol in a diesel takes place so easily
Carelessness is rarely the cause, and nobody means to do it. A diesel nozzle mostly won't fit a petrol vehicle, but the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and just in that direction.
When habit and the vehicle stop matching, it occurs. A vehicle that's new to you — hired, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the drive. A well-known forecourt with the pumps in a different order. Racing for a train at Highbridge & Burnham and fuelling up en route. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that is when. The hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel at your next fill-up in Highbridge
- Read the pump, not the colour. In the UK unleaded handles are normally green and diesel black, but not on each forecourt. The label is what counts.
- In a motor you do not know, look inside the flap over your filler or at the cap before the first fill: many vehicles print the fuel type there.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key if a house has one of each. So label it.
- It sounds daft and it does the trick: on the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- Put your phone away. This is an easy mistake to make while you're thinking about something else.
- Add-on devices are available for motors without one, and some diesels are built with a filler that won't accept a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label.
- Noticing it mid-fill? Stop there and then. A weaker mixture results from less petrol in the tank, yet the next step stays the same: do not start the car.
Petrol already in a diesel in Highbridge? Start here
Then the order of things is short. Starting it is out, and so is switching on your ignition. Ask the staff to help you roll it away from the pump if you are still on the forecourt, whether that's Asda or anywhere else. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it has been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a separate fault — Highbridge has a page just for it.
Why one petrol in a diesel job around Highbridge costs more than another
A fair single quote doesn't exist here: four situations, four separate jobs. Which of them you are in is mostly what shifts the cost. Where the car is matters too, and whether a van can safely reach it, after the ratio of petrol to what your tank holds.
What went in, how much, and if it has run — three queries our engineers ask before pricing, not after, for exactly that reason. Given the answers, you get a straight figure instead of a range.
About Highbridge itself
Highbridge is a coastal village in Somerset, situated near the mouth of the River Brue and close to the Bristol Channel. Highbridge has a low elevation of around 7 metres above sea level and is surrounded by nearby places such as Alstone, Walrow, and Edithmead. Highbridge is predominantly composed of flat housing and is located approximately 14 miles from the city of Wells. Highbridge is also within commuting distance to larger cities, with London being around 124 miles away.
Highbridge and Somerset: where our fuel drain cover runs
Highbridge waits in the TA postcode area, and our teams that answer petrol in diesel jobs there work the locations around it as well — Alstone, Walrow and Edithmead among them. Our engineers drain where the vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the petrol pump in Highbridge?
Then you're in the best spot there is. Keep it turned off, and ring.