Petrol in a Diesel Car in Burn Naze: How Worried Should You Be?
Far less than you probably are, provided it hasn't been started. "Have I wrecked it?" is the first question everyone in Burn Naze asks, and the truthful answer is generally no, because petrol resting in a diesel tank hurts nothing until it's dragged through your fuel system — by ignition priming, by your starter, or by driving. Leave your motor off and call Petrol in Diesel — that is how you keep it that way. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to stop it from happening a second time: that is the remainder of this page.
What petrol in a diesel does to your engine
On its way through an engine, diesel does two jobs. Before it burns, it lubricates — and then it ignites. The high-pressure fuel pump and the injectors are designed to extremely fine tolerances, and the diesel passing through them is what keeps those surfaces from wearing against each other.
Poorly at the first, not at all at the second: that is petrol. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips out the protection the fuel system rests on, and any pump running on that mixture is wearing itself.
Put these together and the shape of the issue is plain. Not contact but circulation is what causes the damage. Where the petrol is only in your tank, it's a fault of fuel, nothing more. A pump that has been running on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with the fuel to your injectors further on.
How bad is petrol in a diesel? Four situations we see around Burn Naze
The best case there can be: filled up, never started. At a forecourt, and really only there, that petrol is still limited to that tank — because everywhere else the car was driven to reach it. The job is draining and cleaning on the spot.
Ignition on, or started for a moment. Petrol has come out of your tank and got to the filter and the fuel lines, because the system has been bled. Still usually easy: drain, flush, and your filter sorted.
Driven a couple of miles. Now the pump has spent these miles labouring on diluted fuel. Tank, lines, filter, then fresh fuel run through the entire system: that is this work, and the way the vehicle was driven matters as much as the miles. The school run to Sacred Heart Catholic Primary School, Thornton Cleveleys is one thing. Very different a second time: a run to Lancaster, under 15 miles away, or some miles on the M55, under 10 miles from Burn Naze, where the motor never stopped labouring hard.
Driven till it complained. Rattling, an uneven idle, smoke, a throttle that has gone soft. That's the motor telling you its fuel has stopped behaving like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Poachers Way. A car pulled over early very seldom has lasting damage, as the fuel drain and the flush, which still come first, deal with it.
Burn Naze people and the 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'll be." Topping up removes nothing; it gives you a fuller tank of the same mix. Percentage is not how a diesel fuel system tolerates petrol, whatever that guidance assumes.
"Modern diesels can handle a little petrol" — a myth, and nearer the reverse. Finer components and higher pressure are the way a current diesel runs its fuel, and that makes the lubrication matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no damage done." Any petrol motor fed diesel generally will not run, and so the motorist stops and the damage stops with them. Whilst the pump wears, a diesel fed petrol normally starts, ticks over and drives away as though nothing has happened. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct fault. It does not put back what petrol has thinned, and the petrol is still inside your tank afterwards.
Myth: "Drain the tank yourself and you are sorted." Once the motor has run, some of that petrol is no longer in that tank: it is in your filter and the lines, and it goes right back through your pump on your next start. It's also really risky to drain petrol into a can by the roadside.
Why petrol in a diesel happens so easily
A careless moment is rarely the cause, and no one means to do it. A diesel nozzle mostly will not fit a petrol car, yet the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake simple, and just in that direction.
When habit and the vehicle stop matching, it happens. A new motor, a hire car or a courtesy car. Two cars on one drive, one petrol, one diesel. A forecourt you know, only with its pumps laid out differently. Rushing for a train outside Poulton-Le-Fylde and fuelling up en route. Years of petrol vehicles behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that is when. The hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
How to prevent petrol in a diesel on your next fill-up in Burn Naze
- Check the pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what matters.
- In a motor you don't know, look inside the flap over your filler or at the cap before your first fill: plenty of vehicles state the fuel there.
- One of each in the house? Mark the key to your diesel — a bright fob, a sticker — because intending to remember isn't enough.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It seems daft and it works.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck the phone away then keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to block a petrol nozzle, and add-on devices are available for motors without one. They are a backstop, not a reason to stop checking the pump.
- Less petrol means a thinner mixture, and so stop the moment you notice — while remembering that your next step is unchanged. It's still not to fire it up.
Already put petrol in a diesel in Burn Naze?
Then the order of things is short. Leave it unstarted, with your ignition switched off too. If you're still on the forecourt — BP or anywhere else — ask the staff to help you roll the vehicle away from the pump. Then call 0333 366 0103 and tell us what went in, roughly how much, and whether it has run.
If it was AdBlue instead of petrol, say so. That's a separate issue — corrosion and deposits instead of lost lubrication — and it has its own page for Burn Naze.
Why one petrol in a diesel job around Burn Naze costs more than another
The four scenarios above are four separate jobs, so no single price for this would be honest. Mostly, your cost moves with which one you are in. The share matters next, meaning how much of your tank is petrol, and then the location of the car and whether getting to it is safe for our van.
Ahead of any quote, not after, we ask three queries: your fuel that was put in, the volume, and if it has run. That is why. The answers change a range into a straight figure.
About Burn Naze and where it is
Burn Naze is a coastal suburban area in Lancashire, situated near the mouth of the River Wyre and close to the seaside town of Cleveleys. Burn Naze has a relatively low elevation of around 6 metres above sea level, reflecting its coastal location. Burn Naze is characterised by its predominantly semi-detached housing stock, which is typical of many suburban areas in the North West of England.
Burn Naze and Lancashire: where our fuel drain cover reaches
Pheasant Wood, Trunnah and Cleveleys are among the locations near Burn Naze that the same teams work, answering petrol in diesel jobs across Burn Naze's FY postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots our engineers drain, and the vehicle does not need to come to us.
Still at the pump in Burn Naze?
Then, you could not be in a better place. Keep the car switched off, and ring.