Should You Worry? Petrol in a Diesel Car in Thornes
Provided it hasn't been started, worry less than you likely are. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through your fuel system — the ignition priming your pump, the starter, or the drive on its own. So the truthful answer to the first query everyone around Thornes asks, "have I wrecked it?", is generally no. Leave the engine off and phone Petrol in Diesel — that is how you keep it that way. Further down, this page sets out what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Your engine and petrol in a diesel: what happens
Two jobs fall to diesel on its route round a motor. Before it combusts, it lubricates — and then it combusts. What keeps the surfaces inside the high-pressure fuel pump and your injectors from wearing against one another is your diesel flowing through them — they're built to very fine tolerances.
Badly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump on that mixture wearing itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is why you hear the rattling.
Combined, those make the shape of the problem plain. Not contact but circulation is what causes the harm. Where the petrol is only inside the tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds travels on, carried by your fuel, into your injectors further along, which is why a pump that has worked on that petrol is where a mechanical issue begins.
Thornes, petrol in a diesel: four cases, from mild to significant
Fuelled but not once started — as good as it gets. Only that tank has petrol in it, so the task is clearing your tank and rinsing your system where the car sits. This scenario can only truly occur on a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a moment. Petrol has left the tank and got to the fuel filter and your lines, because the system has been primed. Drain, flush, deal with the filter: still normally simple.
A few miles driven, and the pump has spent every one of them labouring on weakened fuel. How hard the vehicle was driven counts as much as how far, and this work covers the tank, the lines, the fuel filter and fresh fuel through the entire circuit. On the school run to Methodist Voluntary Controlled Junior, Infant and Nursery School: With Communication Resource, the distance is small. Very different again: a run to Wakefield, under 3 miles away, or any mileage on the M1, under 3 miles from Thornes, where your engine kept working hard.
Driven on until it complained — knocking, smoke, a ragged idle, a dead throttle. The engine is telling you the fuel is no longer behaving like diesel. Pull up wherever you are — the verge on Thornes Park Court, a lay-by, a side street — and leave the vehicle where it is. What comes first is still the fuel drain and flush, and that sorts it out, with permanent damage very uncommon when a car is pulled over early.
What Thornes motorists get told about petrol in a diesel — and the myths in it
False: topping up to full with diesel makes it fine. It does 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 advice presumes.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. Smaller parts and higher pressure are the way a current diesel runs its fuel, and that makes the protection matter more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that fools motorists. The motorist of a petrol motor fed diesel normally stops, because it will not run, and the harm stops there. While the pump grinds, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. A running engine doesn't mean fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, supposed for another problem. What petrol has diluted remains thinned, and that petrol remains inside that tank regardless.
"Drain it yourself and you are sorted" — a myth, since after it's been running some petrol lies in your filter and lines, waiting to go right back through your pump at your next start. It is also genuinely risky to drain petrol into a can by the roadside.
Why petrol in a diesel takes place so easily
It is seldom carelessness, and nobody does it on purpose. 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 mostly won't go into a petrol vehicle at all. So the mistake runs one way.
When habit and your car stop matching, it occurs. Hire cars, courtesy cars, and vehicles that are new to you. A household with one petrol and one diesel on the driveway. A well-known forecourt with the pumps in a different order. A train to catch, and a rushed fill on the way to Wakefield Westgate. The first fill-up in a diesel Volkswagen Passat after years of driving petrol is precisely the moment it occurs. The hand does what it has always done when you add rain, a phone call or a back seat full of children.
Avoiding petrol in a diesel next time you fill up in Thornes
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Read the petrol pump's label; the colour is only a clue.
- Inspect your filler flap. Many cars state the fuel type inside the flap or on the cap. Look at it on your first fill in any vehicle you don't know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of intending to remember, for a household with one of each.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It sounds daft and it works.
- Put your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Some diesels have a filler built to block 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.
- Stop as soon as you realise. Less petrol inside the tank makes a weaker blend. It doesn't change what to do next, which is still not to start it.
Thornes: already put petrol in a diesel?
In that case, there is just a short order of things. Starting it is out, and so is turning on the ignition. Still at the forecourt, at Co-op or anywhere else? Ask the staff to help you roll the vehicle away from the pump. Next, 0333 366 0103. We'll ask what got in, roughly how much, and if it's been run.
Corrosion and deposits form the problem with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and read its own Thornes page.
Why one petrol in a diesel job in Thornes costs more than another
Four different tasks lie behind the four situations above — which is why there's no fair single quote. Mostly, your cost moves with which one you're in. The proportion counts next, meaning how much of the tank is petrol, and then the position of the vehicle and whether reaching it is safe for a technician.
Ahead of any quote, not after, come three questions: your fuel that went in, the quantity, and whether it has run. That's why. The replies turn a range into a straight figure.
About Thornes itself
Thornes is a suburban area located on the riverside in West Yorkshire, with an elevation of 34 metres and situated approximately 1.1 miles from Wakefield. Thornes is characterized by its semi-detached housing and is close to nearby places such as Clayton Hill and Belle Isle. Thornes sits within the wider Wakefield urban area, which is around 160 miles north of London.
Thornes and West Yorkshire: where our fuel drain cover reaches
Clayton Hill, New Brighton and Belle Isle are among the spots around Thornes that the same teams work, answering petrol in diesel jobs across Thornes's WF postcode area. No need to move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots where we work.
Still at the pump in Thornes?
Nothing beats it: that is where you are. Keep it off. Phone.