Should You Worry? Petrol in a Diesel Car in Pembroke
Unstarted? Then less anxious than you likely are. "Have I ruined it?" is the first question anyone in Pembroke asks, and the honest answer is normally no, because petrol left in a diesel tank harms nothing until it is dragged through your fuel system — by ignition priming, by your starter, or by driving. Keep it that way: leave the motor off and call Petrol in Diesel. Further down, this page sets out what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you again.
Petrol in a diesel: what does it do to the engine?
On its way through a motor, diesel has two tasks. It burns, and before it ignites it protects. The high-pressure pump and the injectors are built to extremely fine clearances, and your diesel passing through them is what keeps those surfaces from grinding against one another.
Of these two jobs, petrol handles the first badly and the second never. The clattering comes from petrol being made 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 away the protection your system depends on, and any pump running on that mixture is wearing itself.
The shape of the problem is clear when you put those together. Contact doesn't do the damage — circulation does. A tank with petrol in it is a fuel problem. The beginning of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with the fuel to your injectors downstream.
Petrol in a diesel around Pembroke: how bad is it? Four cases
Filled up, never started. The best case there can be. Being on a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With that petrol held inside that tank alone, it's emptied and flushed on the spot, and nothing more is needed.
A moment's running, or merely the ignition on. The system has been bled, so petrol has left the tank and reached the filter and your lines. Still usually easy: drain, flush, and your filter sorted.
Those few miles on the road were the pump labouring on fuel weakened by petrol the whole way. Tank, lines, filter, then fresh fuel put through the entire system: that's this work, and the way the car was driven counts as much as the miles. Driving the kids to the local primary school is one kind of trip. A run as far as St Davids, under 25 miles away, is a very different task. So is any mileage on the M4, under 50 miles from Pembroke, where the engine has been running hard throughout.
Driven on till it protested — rattling, smoke, a lumpy idle, a dead throttle. The fuel isn't behaving like diesel any more, and the motor is saying so. Pull up wherever you are — the verge on Main Street, a lay-by, a side street — then leave the vehicle where it is. The drain and flush still go first, and they deal with it: when a car is stopped early, permanent damage is very unusual.
Pembroke motorists and that petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a fuller tank, still the same mix. Percentage isn't how a diesel fuel system tolerates petrol, however much that guidance supposes.
If anything, the opposite holds. Myth: "A newer diesel can cope with a bit of petrol." At higher pressure, through more precise parts: that is how a modern diesel handles its fuel, and so the protection counts more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up most people than any other. Any petrol engine fed diesel normally will not run, and so the motorist stops and the damage stops with them. Feed petrol to a diesel and it usually fires up, ticks over and pulls away like nothing has happened — all the while its pump wears. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate fault. What petrol has weakened stays diluted, and that petrol remains in your tank anyway.
The next start draws petrol back round your pump out of the lines and the fuel filter, where some of that sits once the motor has run. That's why draining your tank yourself does not sort it — a myth. It's also truly dangerous to drain petrol into a can at the kerbside.
Petrol in a diesel: how does it happen?
It's seldom carelessness, and no one does it on purpose. The petrol nozzle is the smaller of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol motor at all. The forecourt makes it simple, and the error runs one way.
Routine and your car falling out of step is when it takes place. Hire cars, courtesy cars, and cars that are new to you. One petrol and one diesel on the drive of the same household. A forecourt you know, only with its pumps arranged differently. Racing for a train at the nearest station and filling up en route. Precisely the moment it occurs: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. Throw in rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Next time you fill up in Pembroke: avoiding petrol in a diesel
- The label is what counts, so read the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- The first fill in a new motor is the time to check your filler flap — inside it, or on the cap, many vehicles state the fuel to use.
- One of each in the house? Mark your key to your diesel — a coloured fob, a sticker — because intending to remember is not enough.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new motor, say "diesel" out loud. Daft, yes, but it works.
- Put your phone away. This is an easy mistake to make while 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 add-on devices are available for the rest. Treat it as a backstop, and keep reading the petrol pump.
- Less petrol makes a weaker mixture, and so stop as soon as you notice — while remembering that the next stage is unchanged. It's still not to start the car.
Already put petrol in a diesel around Pembroke?
Then, there's just a short order of things. Never start the vehicle, and don't switch your ignition on. Yet at the forecourt, at Tesco or anywhere else? Ask the staff to help you roll it away from the petrol pump. Call 0333 366 0103 next, with three answers — the fuel, the approximate volume, and if it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different fault — Pembroke has a page all for it.
One petrol in a diesel job in Pembroke costs more than another. Why?
Four separate jobs lie behind the four scenarios above — which is why there is no fair single price. Which of them you're in is chiefly what shifts the cost. After that it's the proportion — how much petrol got in against how much that tank takes — and after that where the car is and whether our van can reach it safely.
Before any quote, not after, come three questions: your fuel that went in, its quantity, and whether it has run. That's why. Those replies are what change a range into one firm number.
About Pembroke and where it is
Pembroke is a coastal town in southwest Wales, situated near the mouth of the River Cleddau at an elevation of around 16 metres. Pembroke sits within Pembrokeshire, close to nearby places such as Green, Orange Gardens, and Golden Hill. Pembroke has a population of approximately 7963 people, predominantly living in detached housing. Pembroke is located near the city of St Davids, about 20.7 miles away, and is around 205.7 miles from London.
Pembroke and Pembrokeshire: where our fuel drain cover runs
Green, Orange Gardens and Golden Hill are among the places around Pembroke that the same vans work, answering petrol in diesel calls across Pembroke's SA postcode area. We drain where your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
In Pembroke and still at the petrol pump?
Nothing beats it: that's where you now are. Call, and keep it turned off.