How Worried Should You Be? Petrol in a Diesel Car in Hurtmore
Not started? Then less anxious than you probably are. "Have I wrecked it?" is the first thing anyone around Hurtmore asks, and the truthful answer is normally no, since petrol resting in a diesel tank harms nothing till it's drawn through the fuel system — by ignition priming, by your starter, or by driving. To leave the car like that, phone Petrol in Diesel and leave the engine switched off. What petrol actually does to a diesel, how to gauge how far it's travelled, and how to stop it from happening again: that is the rest of this page.
What petrol in a diesel does to the motor
Passing through a motor, diesel is doing two things at the same time. Before it burns, it lubricates — and then it ignites. Designed to very fine tolerances, your injectors and the pump depend on the diesel moving through them to keep their surfaces from wearing against one another.
Poorly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump running on the blend to wear itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the rattling.
The shape of the trouble is clear once you put those together. Contact doesn't do the damage — movement does. All a tank with petrol in it amounts to is a fuel problem. Whatever a worn pump sheds travels on, borne by your fuel, into the injectors further along, which is why a pump that has worked on the petrol is where a mechanical problem begins.
Hurtmore, petrol in a diesel: four situations, from mild to significant
Fuelled, and never started: no case is better. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol held inside your tank alone, it's cleared and cleaned on the spot, and nothing more is needed.
Your ignition turned on, or a short start. Once primed, the system has drawn petrol from that tank as far as the fuel filter and your lines. Still normally simple: drain, flush, and the fuel filter sorted.
Those few miles on the road meant your pump working on fuel diluted by petrol the whole way. Tank, lines, filter, then fresh fuel run through the entire system: that's this work, and the way the vehicle was driven matters as much as the miles. A school run to Loseley Fields Primary School is one matter. Any distance on the M3, under 10 miles from Hurtmore, means your engine working hard throughout, and a run to Chichester, under 50 miles away, makes a very different job too.
Driven on till it protested — clattering, smoke, an uneven idle, a soft throttle. What you are hearing is the motor reporting fuel that no longer behaves like diesel. Whether it's the verge on Mark Way, a lay-by or a side road, stop there and leave it. The fuel drain and flush-through still go first, and they deal with it: when a car is stopped soon, long-term damage is very uncommon.
Hurtmore people and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Nothing comes out when you top up — that tank simply holds more of the same blend. Percentage isn't how a diesel fuel system copes with petrol, whatever that advice assumes.
Myth: a newer diesel copes with a bit of petrol. Rather, the opposite. A newer diesel runs its fuel through smaller parts at higher pressure, which makes the lubrication count more, not less.
"It starts, it drives, and so there is no harm" — the myth that trips up more people than any other. Diesel in a petrol motor usually means a motor that won't run: the motorist stops, and so does the harm. Whilst the pump grinds, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. Being able to run is not proof of being fine.
An old workaround for a separate fault lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has diluted remains weakened, and that petrol remains inside your tank regardless.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol sits in the fuel filter and lines, waiting to go straight back through your pump at the next start. Emptying petrol into a can by the kerbside is also really dangerous.
How does petrol in a diesel take place?
No one does it on purpose, and it is seldom carelessness. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol vehicle at all. The forecourt makes it easy, and the mistake runs one way.
The moment habit stops matching your car is the moment it happens. A new vehicle, a hire car or a courtesy car. One petrol and one diesel on the drive of the same household. Your ordinary forecourt, its pumps suddenly in a different order. Filling up in a rush on the way to Godalming, with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. Throw in a back seat full of children, a phone call or rain, and habit takes over.
Next time you fill up in Hurtmore: avoiding petrol in a diesel
- Green for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Go by the label on the pump, not the colour.
- Plenty of cars state the fuel inside your filler flap or on the cap, so check there on your first fill in any car you don't know.
- One of each in the house? Label your key to the diesel — a coloured fob, a sticker — because intending to remember isn't enough.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump. It seems daft and it works.
- Mistakes like this are easy to make whilst your mind is on something else, and so your phone goes away.
- Add-on devices are available for vehicles without one, and some diesels come with a filler that will not accept a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label.
- Stop as soon as you realise. Less petrol in your tank makes a thinner mixture. It does not change what to do next, which is still not to crank it.
Petrol already in a diesel around Hurtmore? Begin here
Short and simple, then, is the order of things. Starting it is out, and so is switching on your ignition. The staff on the forecourt — whether at Shell itself or wherever you filled up — will usually help push it away from the pump if you ask. Next, 0333 366 0103. We will ask what went in, about how much, and if it's been run.
If it was AdBlue rather than petrol, say so. That is a different fault — corrosion and deposits rather than lost protection — and it has its own page for Hurtmore.
Hurtmore petrol in a diesel tasks: why one costs more than another
There's no honest single price for this, because the four scenarios above are four different jobs. The situation itself does most of the work of moving the cost. After that it is the share — how much petrol went in against how much the tank takes — and after that where the vehicle is and whether our van can reach it safely.
What went in, how much, and if it has run — three queries we ask before pricing, not after, for precisely that reason. Their answers are what change a range into one firm number.
About Hurtmore itself
Hurtmore is a small village in Surrey, situated inland at an elevation of around 103 metres. Hurtmore lies approximately 30 miles south-west of London and is close to the nearby settlements of Binscombe, Norney, and Frith Hill. Hurtmore has a population of around 932 people and is characterised by predominantly detached housing. Hurtmore is also near the city of Chichester, which is about 26 miles away.
Across Surrey and around Hurtmore: fuel drain cover
Hurtmore rests in the GU postcode area, and our teams that answer petrol in diesel call-outs there work the locations around it as well — Binscombe, Norney and Frith Hill among them. Our engineers drain where your car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Hurtmore: still at the pump?
Then you are in the best position there can be. Leave the vehicle turned off, and ring.