Petrol in a Diesel Car in Coates: How Worried Should You Be?
If it hasn't been started, worry far less than you probably are. "Have I ruined it?" is the first question anyone in Coates asks, and the honest answer is normally no, because petrol resting in a diesel tank harms nothing until it's drawn through your fuel system — by ignition priming, by your starter, or by being driven. Leave the motor off then call Petrol in Diesel — that keeps it like that. The remainder of this page covers what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
Your engine and petrol in a diesel: what goes on
Passing through an engine, diesel is doing two things at once. Lubricating comes before burning; it does both. Extremely fine clearances are built into the injectors and your high-pressure pump, and just your diesel flowing through keeps those surfaces from grinding together.
Of those two tasks, petrol handles the first badly and the second never. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so a pump on the blend to wear itself. It's equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the knocking.
Combined, those make the shape of the problem plain. Not contact but movement is what does the harm. A tank with petrol in it is a fuel issue. Whatever a worn pump sheds travels on, carried by your fuel, into your injectors downstream, which is why a pump that has worked on that petrol is where a mechanical problem starts.
Petrol in a diesel in Coates: how bad is it? Four situations
Fuelled, and never started: nothing beats it. The petrol is in that tank and just that tank, and the job is a drain and a flush where the vehicle stands. This is the one scenario that can only truly take place on a forecourt, since anywhere else the car has been driven to get there.
Started for a moment, or only the ignition on. The system has been bled, so petrol has left the tank and reached the fuel filter and your lines. That's usually still an easy task — a drain, a flush, and the filter dealt with.
A few miles driven, and the pump has spent each of them working on thinned fuel. How hard the vehicle was driven matters as much as how far, and this work covers your tank, the fuel lines, your filter and clean fuel through the whole system. The school run to Coates Primary School is one matter. Any mileage on the Great North Road, under 10 miles from Coates, means your engine has worked hard throughout, and a run to Peterborough, under 10 miles away, makes a very different task as well.
Driven on till it complained — clattering, smoke, a ragged idle, a dead throttle. That's your motor telling you its fuel has stopped acting like diesel. Pull up where you are — on the verge on A605, at the kerb, down a side road — and do not move it. The drain and flush still go first, and they take care of it: when a car is pulled over soon, long-term damage is very rare.
Coates people and that petrol in a diesel stories they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing is removed by topping up — you are left with a fuller tank, still the same mix. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance assumes.
If anything, the reverse is true. Myth: "A current diesel can cope with a bit of petrol." At higher pressure, through more precise components: that's how a modern diesel moves its fuel, so the lubrication matters more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that catches motorists. The motorist of a petrol motor fed diesel normally has no choice but to stop, because it will not run, and the damage stops with them. A diesel fed petrol normally starts, idles and drives away as if nothing has happened, while the pump wears. Running does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different fault. The petrol is still in that tank afterwards, and whatever it has thinned is not put back.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol sits in the filter and lines, waiting to go right back through your pump at the next start. Clearing petrol into a can at the roadside is also genuinely dangerous.
How does petrol in a diesel occur?
A careless moment is rarely the cause, and nobody means to do it. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol vehicle at all. The forecourt makes it simple, and the mistake runs one way.
It occurs when routine and the car stop matching. Hire cars, courtesy cars, and motors that are new to you. Two vehicles on one drive, one petrol, one diesel. A forecourt you know, only with its pumps laid out differently. Rushing for a train outside Whittlesea and fuelling up en route. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: exactly when it happens. Add a back seat full of children, a phone call or rain, and habit takes over.
Coates people: how to prevent petrol in a diesel next time
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Read the petrol pump's label; the colour is just a hint.
- Many vehicles state the fuel inside your filler flap or on the cap, so check it on the first fill in a vehicle you don't know.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key when a house has one of each. So mark it.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump. It sounds daft and it does the trick.
- Tuck the phone away. This is an easy mistake to make whilst you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to refuse a petrol nozzle, and aftermarket devices are available for the rest. Count it as a backstop, then keep checking the petrol pump.
- Spotting it mid-fill? Stop at once. A weaker blend follows from less petrol inside that tank, but your next stage remains the same: don't start it.
Already put petrol in a diesel in Coates?
Then the order of things is brief. Don't crank it, and don't turn your ignition on. If you are still at the forecourt — BP or anywhere else — ask the staff to help you roll the vehicle away from the pump. Then phone 0333 366 0103 and tell us what got in, about how much, and if it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a different fault — Coates has a page all for it.
One petrol in a diesel task around Coates costs more than another. Why?
Four different tasks lie behind the four scenarios above — which is why there's no fair single quote. What shifts your cost is mostly which of them you're in. Where the vehicle is counts too, and whether a van can safely get to it, after the share of petrol to what your tank holds.
That is why we ask three queries before costing instead of after: what was put in, how much, and whether it's run. Those answers are what turn a range into one firm number.
About Coates itself
Coates is a village in Cambridgeshire, situated inland near the city of Peterborough. Coates lies close to the villages of Oldeamere, The Lipneas, and Eastrea, in a low-lying area with an elevation of around 6 metres. Coates has a population of approximately 1437 people, predominantly living in detached houses. Coates is located about 72.9 miles from London, making it a rural community within commuting distance of the capital.
Coates and Cambridgeshire: where our fuel drain cover runs
Coates sits in the PE postcode area, and the vans that answer petrol in diesel calls there work the places around it as well — Oldeamere, The Lipneas and Eastrea among them. The vehicle does not need to come to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Coates: still at the pump?
Then you're in the best position there can be. Turned off it stays; then call.