Hollybush: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, provided it has not been started. Petrol resting in a diesel tank does nothing to your engine until something pulls it through the system — the ignition priming your pump, your starter, or the drive on its own. So the truthful answer to the first query everyone in Hollybush asks, "have I wrecked it?", is normally no. Keep it that way: leave your motor off and call Petrol in Diesel. What petrol actually does to a diesel, how to judge how far it has travelled, and how to stop it from happening a second time: that's the remainder of this page.
Inside the motor: what petrol in a diesel does
Passing through a motor, diesel does two jobs at once. Lubricating comes before burning; it does both. What keeps the surfaces inside your high-pressure pump and the injectors from wearing down against one another is the diesel flowing through them — they are built to very fine gaps.
Poorly at the first, not at all at the second: that's petrol. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips out the lubrication the fuel system rests on, and any pump working on that mixture is wearing itself.
Combined, those make the shape of the problem clear. The harm is done by movement, not by contact. Any tank with petrol in it is a fuel problem. Whatever a worn pump sheds goes on, borne by your fuel, into the fuel injectors further along, which is why a pump that has been working on that petrol is where a mechanical fault starts.
Petrol in a diesel around Hollybush: how serious is it? Four cases
Filled up, not once started. The best case there can be. On a forecourt, and really only there, the petrol is still confined to the tank — since everywhere else your car was driven to reach it. The job is draining and purging on the spot.
Started for a moment, or just your ignition on. The system has been bled, and so petrol has left your tank and got to your filter and the lines. Normally nothing more than emptying, flushing and sorting the fuel filter, and so still simple.
Driven a few miles. Now your pump has spent these miles working on weakened fuel. How hard the vehicle was driven counts as much as how far, and the work covers your tank, the lines, the fuel filter and clean fuel through the entire circuit. Short trips, like the school run to the local primary school, are one matter. A run as far as Newport, under 5 miles away, is a very different job. So is any mileage on the M4, under 3 miles from Hollybush, where the motor has been working hard throughout.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The fuel is not acting like diesel any more, and the motor is telling you. Stop on the spot — on the verge on Hollybush Way, at the kerb, down a side road — and don't move it again. A vehicle pulled over early very seldom has lasting damage, as the drain and the flush-through, which still come first, deal with it.
What Hollybush 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. Topping up takes out nothing; it gives you a fuller tank of the same mixture. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance supposes.
"Current diesels can handle a little petrol" — a myth, and nearer the reverse. At higher pressure, through smaller components: that is how a newer diesel handles its fuel, and so the protection matters more, not less.
The myth that catches people out: if it starts and drives, it must be unharmed. Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the damage. A diesel fed petrol normally starts, idles and drives away as though nothing has happened, whilst your pump grinds. Running does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate fault. What petrol has weakened stays weakened, and the petrol stays inside your tank anyway.
Once your engine has been run, part of the petrol sits in the filter and your lines, not the tank — and your next start sends it straight back through your pump. So the myth "drain your tank yourself and you're sorted" doesn't hold. Clearing petrol into a can at the roadside is also really risky.
How does petrol in a diesel occur?
Carelessness is seldom the cause, and no one means to do it. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle generally won't go into a petrol vehicle at all. So the error runs one way.
Habit and your car falling out of step is when it happens. A new car, a hire car or a courtesy car. Two motors on one drive, one petrol, one diesel. The pumps in a different order on a familiar forecourt. A rushed fill en route to Cwmbran with a train to catch. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Passat for the first time. Throw in a back seat full of children, a phone call or rain, and the hand takes over.
How to prevent petrol in a diesel at your next fill-up around Hollybush
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Check the petrol pump's label; the colour is just a clue.
- The first fill in a strange car is the time to check the filler flap — on it, or on the cap, many cars state which fuel they take.
- Mark your key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car needs its first tank. It seems daft. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away then keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to block a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop reading the petrol pump.
- Less petrol makes a thinner mix, and so stop as soon as you realise — while remembering that your next step is unchanged. It is still not to crank it.
Already put petrol in a diesel around Hollybush?
Short and simple, then, is the order of things. Starting it is out, and so is switching on the ignition. If you are still at the forecourt — Shell or anywhere else — ask the staff to help you roll the vehicle away from the petrol pump. Then ring 0333 366 0103 and tell us what went in, about how much, and if it's run.
Say so if it was AdBlue rather than petrol: it is a different issue, with its own page for Hollybush, since AdBlue brings corrosion and deposits instead of lost protection.
Why one petrol in a diesel task in Hollybush costs more than another
Four different tasks lie behind the four situations above — which is why there's no fair single price. What moves your cost is mostly which of them you're in. Where the vehicle is matters too, and whether a technician can safely get to it, after the ratio of petrol to what your tank takes.
Three questions come first, before quoting, instead of after — what went in, how much, has it run — and this is the reason. A range turns into a straight figure when the answers are in.
About Hollybush, briefly
Hollybush is a suburban area in Torfaen, situated on the riverside at an elevation of 84 metres, with terraced housing being the predominant type of accommodation. Hollybush lies close to the city of Newport, approximately 3.8 miles away, and is near other local places such as Coed Eva and Two Locks. Hollybush has a population of around 4195 people and is located near the St Dials area. Hollybush is part of the wider urban area surrounding Newport, with London being around 125 miles away.
Fuel drain cover in Hollybush and across Torfaen
Coed Eva, Two Locks and St Dials are among the places near Hollybush that the same teams work, answering petrol in diesel calls across Hollybush's NP postcode area. A forecourt, a supermarket car park, a lay-by or your own drive are all spots our technicians drain, and your car doesn't need to come to us.
In Hollybush and still at the petrol pump?
In that case, you couldn't be in a better spot. Leave the car turned off, and ring.