How Worried Should You Be? Petrol in a Diesel Car in The Bourne
Far less than you likely are, provided it hasn't been started. Everyone in The Bourne starts with "have I wrecked it?", and the honest answer is normally no: petrol left in your tank of any diesel stays harmless until priming, cranking or driving pulls it into the system. Leave the engine off and call Petrol in Diesel — that is how you keep it like that. The remainder of this page explains what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
What petrol in a diesel does to the motor
On its way through a motor, diesel has two jobs. It lubricates to begin with, and after that does it burn. Made to extremely fine gaps, your injectors and the pump rely on the diesel moving through them to keep their surfaces from wearing against one another.
Petrol does the first task poorly and the second not at all. It's thinner than diesel and strips away the lubrication the fuel system depends on, and so a pump running on a petrol blend 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 clattering comes from.
Put those together and the shape of the issue is plain. Contact does not do the damage — circulation does. Petrol in a tank is a fuel issue. A pump that has been working on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the injectors downstream.
Petrol in a diesel around The Bourne: how bad is it? Four situations
Fuelled up, never started. The best case there is. Just the tank has petrol in it, and so the task is draining that tank and rinsing your system where the car sits. This situation can only really occur on a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a second. With your system primed, the fuel lines and filter now contain petrol that has come from the tank. Usually nothing more than clearing, cleaning and sorting the filter, and so still straightforward.
Driven a few miles. Now your pump has spent those miles running on thinned fuel. The work is your tank, your lines, the filter and clean fuel through the entire circuit, and how hard the car was driven counts as much as how far. Driving the children to St Peter's CofE Primary School is one sort of trip. Getting as far as Winchester, under 25 miles away, makes a very different job — as does any distance on the M3, under 10 miles from The Bourne, with the motor labouring hard all the way.
Rattling, an uneven idle, smoke, a throttle gone soft: driven till it complained. What you are hearing is your motor signalling fuel that no longer runs like diesel. Whether it's the verge on Longdown Close, a lay-by or a side street, stop there then leave it. What comes first is still the drain and flush-through, and that takes care of it, with permanent damage very rare if a car is stopped early.
Petrol in a diesel stories The Bourne people hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Nothing is removed by topping up — you're left with a fuller tank, still the same mixture. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance supposes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. A newer diesel sends its fuel through smaller parts at higher pressure, which makes the protection matter more, not less.
The myth that catches drivers off guard: if it starts and drives, it must be unharmed. The driver of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the harm stops with them. A diesel fed petrol usually starts, ticks over and drives away as though nothing has happened, while the pump wears. Being able to run isn't proof of being fine.
Myth: a two-stroke additive makes it safe to drive home. It was an old workaround, supposed for another issue. None of what petrol thinned is put back by it — and afterwards, the tank still holds the petrol.
If the engine has run, part of that petrol is in your filter and the fuel lines, not your tank — and the next start pulls it right back through the pump. So the myth "drain that tank yourself and you are sorted" doesn't hold. Besides, petrol emptied into a can by the road is genuinely dangerous.
Why petrol in a diesel occurs at all
No one does it on purpose, and it is rarely carelessness. A diesel nozzle mostly will not go into a petrol car, but the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and just in that direction.
Routine and the car falling out of step is how it occurs. Courtesy car, hire car, or a car that's brand new. A household with one petrol and one diesel on the drive. Your normal forecourt, its pumps suddenly in a different order. A train to catch, and a rushed fill en route to Farnham. Years of petrol motors behind you, a diesel Volkswagen Tiguan in front of you on the forecourt for its first tank — that is when. With rain, a call coming in, or children to deal with, the hand simply does what it has always done.
How to prevent petrol in a diesel at your next fill-up in The Bourne
- Green for unleaded and black for diesel is usual in the UK — yet not on each forecourt. Go by the label on the pump, not the colour.
- Inspect the filler flap. Many cars state the fuel type inside the flap or on the cap. Look at it on the first fill in a motor you don't know.
- Mark the key. In a house with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- "Diesel", aloud, before you lift the nozzle — every time a new or hired car needs its first tank. It seems daft. It does the trick.
- Mistakes like this are easy to make while your mind is on something else, and so the phone goes away.
- Some diesels come with a filler built to reject a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- Stop the moment you realise. Less petrol inside the tank makes a weaker blend. It doesn't change what to do next, which is still not to fire it up.
Already put petrol in a diesel in The Bourne?
Then the order of things is short. Don't turn your ignition on, and don't start it. Still at the forecourt, at Texaco or anywhere else? Ask the attendants to help you push the vehicle clear of the petrol pump. Next, 0333 366 0103. We will ask what was put in, about how much, and if it's been run.
Corrosion and deposits form the issue with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and see its own The Bourne page.
What makes one The Bourne petrol in a diesel job cost more than the next
A fair single price does not exist here: four scenarios, four separate jobs. Which of them you are in is mostly what shifts your cost. The ratio matters next, meaning how much of that tank is petrol, followed by the location of the car and whether getting to it is safe for a van.
That's why our engineers ask three questions before quoting instead of after: what was put in, how much, and if it has run. With the answers, there is a straight figure rather than a range.
About The Bourne and where it is
The Bourne is a suburban area in Surrey, situated near the River Wey and characterised by its detached housing stock. The Bourne sits at an elevation of 111 metres, with nearby areas including Middle Bourne, Boundstone, and Lower Bourne. The Bourne is located approximately 36 miles from London and 24 miles from Winchester, making it a commuter base for those working in larger cities. The Bourne has a population of around 2276 residents, who enjoy its riverside setting and surrounding countryside.
The Bourne and Surrey: where our fuel drain cover runs
The Bourne waits in the GU postcode area, and our teams that answer petrol in diesel jobs there work the locations near it as well — Middle Bourne, Boundstone and Lower Bourne among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots our engineers work, and the vehicle does not need to come to us.
In The Bourne and still at the petrol pump?
Then, you could not be in a better spot. Keep the car turned off, then ring.