Western Bank: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less anxious than you likely feel. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through your fuel system — your ignition priming your pump, your starter, or driving itself. So the fair answer to the first question everyone around Western Bank asks, "have I ruined it?", is generally no. Leave your motor off then call Petrol in Diesel — that is how you keep it that way. The rest of this page covers what petrol really does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
Inside the motor: what petrol in a diesel does
On its way through an engine, diesel has two jobs. Before it ignites, it lubricates — and then it combusts. Extremely fine gaps go into your injectors and the high-pressure pump, and just your diesel flowing through keeps those surfaces from grinding together.
The second task petrol does not do at all, and the first it does poorly. It's runnier than diesel and takes away the lubrication the system hinges on, so a pump running on a petrol mix is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That's where the rattling comes from.
Together, those make the shape of the issue clear. It is circulation that causes the damage, not contact. Petrol in the tank is a fuel problem. The start of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with your fuel to the injectors downstream.
Four situations our technicians see in Western Bank: how bad is petrol in a diesel?
Filled up, and never started: no case is better. Only your tank has petrol in it, so the task is emptying your tank and flushing your system where the car stands. This scenario can only really happen on a forecourt: anywhere else, the vehicle got there by being driven.
The ignition switched on, or a brief start. Once primed, your system has drawn petrol from that tank up to your filter and the fuel lines. Drain, flush, see to the fuel filter: still normally straightforward.
Some miles driven, and your pump has spent each of them labouring on diluted fuel. Miles is only half of it; how hard it was driven matters equally. Either way this work runs to your tank, the fuel lines, your filter and clean fuel through the whole circuit. Short trips, like the school run to Wigton Nursery and Infant School, are one thing. Getting as far as Carlisle, under 15 miles away, makes a very different job — as does any distance on the M6, under 15 miles from Western Bank, with your engine working hard all the way.
Driven on until it protested — rattling, smoke, a lumpy idle, a dead throttle. What you are hearing is the engine reporting fuel that no longer acts like diesel. Pull up wherever you are — the verge on Wasdale, a lay-by, a side street — then leave it there. A vehicle stopped quickly very seldom has long-term damage, because the drain and the flush-through, which still go first, deal with it.
Stories Western Bank people hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Topping up removes nothing; it gives you a fuller tank of the same mix. The idea behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." A modern diesel runs its fuel through more precise parts at higher pressure, which makes the lubrication matter more, not less.
"It starts, it drives, so there is no harm" — the myth that trips up more drivers than any other. Diesel in a petrol motor normally leaves a motor that won't run: the driver stops, and so does the harm. Feed petrol to a diesel and it normally starts, idles and pulls away as if nothing has happened — all the while its pump is wearing. Running does not mean fine.
An old workaround for a separate fault lies behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has diluted remains thinned, and the petrol stays in that tank regardless.
Myth: "Drain your tank yourself and you are sorted." Once your engine has been run, some of that petrol is no longer inside your tank: it's in the filter and your lines, and it goes right back through your pump at your next start. Besides, petrol emptied into a can by the road is truly dangerous.
Petrol in a diesel: how does it happen?
No one does it on purpose, and it is seldom carelessness. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one mostly won't fit a petrol car. That is how the forecourt makes it straightforward.
Routine and the vehicle getting out of step is when it takes place. Any motor that is new to you — hired, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the driveway. A forecourt you know, only with its pumps laid out differently. A train to catch, and a rushed fill on the way to Wigton. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: exactly when it happens. Throw in a back seat full of children, a phone call or rain, and the hand wins.
Avoiding petrol in a diesel next time you fill up in Western Bank
- Read the petrol 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.
- The first fill in an unfamiliar car is the time to check your filler flap — inside it, or on the cap, plenty of vehicles state the fuel to use.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a home with one of each.
- "Diesel", aloud, before you lift the nozzle — every time a new or hired car needs its first tank. It sounds silly. It works.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away then keep your mind on the petrol pump.
- Add-on devices are available for cars without one, and some diesels are built with a filler that won't take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- As soon as you realise, stop: less petrol inside the tank means a weaker mix. What to do next doesn't change, though — still do not crank it.
Already put petrol in a diesel in Western Bank?
The order of things is brief, then. Starting it is out, and so is turning on the ignition. If you are still on the forecourt — BP or anywhere else — ask the staff to help you roll the car away from the pump. Next, 0333 366 0103. We will ask what went in, roughly how much, and if it's been run.
Corrosion and deposits are the issue with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and read its own Western Bank page.
One petrol in a diesel job in Western Bank costs more than another. Why?
There's no fair single price for this, since the four situations above are four different jobs. Which of them you're in is mostly what moves your cost. The proportion counts next, meaning how much of the tank is petrol, followed by the location of your car and whether reaching it is safe for a van.
What got in, how much, and if it's run — three questions our engineers ask before costing, not after, for exactly that reason. A range becomes a straight figure when those replies are in.
About Western Bank and where it is
Western Bank is a suburban area situated on the riverside in Cumbria, with an elevation of 33 metres, and is located near the city of Carlisle. Western Bank has a mix of housing types, but is predominantly characterised by terraced homes. Western Bank is close to other nearby places such as Station Hill and Wigton, and is about 10.9 miles from Carlisle. Western Bank is a relatively small community with a population of around 1190 people.
Fuel drain cover in Western Bank and across Cumbria
Western Bank waits in the CA postcode area, and the vans that answer petrol in diesel jobs there work the places near it as well — Station Hill, Wigton and Aikhead among them. We drain wherever the vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Western Bank: still at the pump?
No position is better: that's where you are. Leave the car switched off, and ring.