Should You Worry? Petrol in a Diesel Car in Hill End
Unstarted? Then less anxious than you probably are. Until your ignition primes your pump, your starter cranks, or the vehicle is driven, petrol in a diesel tank just sits there and does no harm. Which means the truthful reply to that first Hill End query — "have I wrecked it?" — normally no. Leave the engine off then call Petrol in Diesel — that keeps it like that. 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 a second time.
What petrol in a diesel does to your engine
Diesel does two jobs on its way through a motor. It protects first, and only then does it burn. The high-pressure fuel pump and the injectors are made to extremely fine gaps, and your diesel passing through them is what stops those surfaces from wearing against one another.
Petrol does the first task poorly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump running on the blend wearing itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the clattering.
Combined, those make the shape of the trouble plain. The damage is done by movement, not by contact. Petrol in a tank is a fuel problem. 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 the fuel to your injectors downstream.
Four scenarios we see in Hill End: how bad is petrol in a diesel?
Filled but not once started — the best it gets. At a forecourt, and truly only there, that petrol is still limited to the tank — since everywhere else the car was driven to get to it. The task is draining and rinsing on the spot.
Started for a moment, or only the ignition on. Once primed, the system has pulled petrol from the tank as far as your filter and your lines. Usually little more than emptying, rinsing and seeing to the filter, so still easy.
The pump now spent a few miles on diluted fuel — that is what driving the vehicle meant. The work is the tank, your lines, the filter and fresh fuel through the whole system, and how hard the vehicle was driven counts as much as how far. On the school run to St Peter's Droitwich CofE Academy, the mileage is short. A run as far as Worcester, under 10 miles away, is a very different task. So is any miles on the M5, under a mile from Hill End, where the motor has been labouring hard throughout.
Driven until it protested. Clattering, a ragged idle, smoke, a throttle that has gone soft. The motor is telling you your fuel is no longer behaving like diesel. Stop on the spot — on the verge on Crutch Lane, at the kerb, down a side road — and don't move it again. What goes first is still the fuel drain and flush, and that takes care of it, with permanent damage very rare when a vehicle is pulled over soon.
Petrol in a diesel stories Hill End motorists hear
False: topping up to full with diesel makes it fine. It does not. Topping up takes out nothing; it gives you a fuller tank of the same mixture. That advice supposes a diesel fuel system tolerates petrol by percentage. It doesn't.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. At higher pressure, through more precise parts: that is how a modern diesel moves its fuel, and so the lubrication counts for more, not less.
One myth that catches drivers off guard: if it starts and drives, it must be unharmed. Any petrol engine fed diesel normally will not run, and so the driver stops and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump wears. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the car home." It is an outdated fix for a separate problem. None of what petrol diluted gets put back by it — and afterwards, the tank still contains the petrol.
If the engine has been run, part of the petrol is in your filter and the lines, not that tank — and the next start sends it straight back through your pump. So the myth "drain the tank yourself and you are sorted" doesn't hold. Also, a can of petrol filled by the kerbside is truly risky.
How it happens: petrol in a diesel
A careless moment is seldom the cause, and nobody means to do it. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol car at all. The forecourt makes it easy, and the slip runs one way.
The moment habit stops matching the car is the moment it takes place. Any vehicle that is new to you — a hire car, on loan as a courtesy car, or brand new. One petrol and one diesel on the drive of the same household. A familiar forecourt with the pumps in a different order. A rushed fill en route to Droitwich Spa with a train to catch. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. Throw in a back seat full of kids, a phone call or rain, and habit wins.
Hill End drivers: how to prevent petrol in a diesel next time
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Read the pump's label; the colour is only a clue.
- In a car you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of cars state the fuel there.
- Label the key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car needs its first tank. It seems daft. It works.
- While you are thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- The moment you notice, stop: less petrol in that tank makes a weaker mix. What to do next doesn't change, though — still don't start it.
Hill End: already put petrol in a diesel?
In that case, there's only a short order of things. Do not switch your ignition on, and do not start it. If you're still at the forecourt — Valero or anywhere else — ask the staff to help you push it away from the petrol pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it's been run.
Say so if it was AdBlue rather than petrol: it is a separate fault, with its own page for Hill End, since AdBlue brings corrosion and deposits instead of lost lubrication.
Hill End petrol in a diesel jobs: why one costs more than another
The four situations above are four separate tasks, so no single price for this would be fair. What shifts the cost is chiefly which of them you are in. After that it is the share — how much petrol was put in against how much your tank takes — and after that where your car is and whether a technician can reach it safely.
Ahead of any quote, not after, come three queries: your fuel that got in, its quantity, and whether it has run. That is why. Those answers turn a range into a straight figure.
About Hill End and where it is
Hill End is a suburban area in Worcestershire, situated on the riverside at an elevation of 46 metres, with The Vines and Netherwich nearby. Hill End is located close to the city of Worcester, approximately 6.4 miles away, and is also near Droitwich Spa. Hill End has a population of around 2535 people and predominantly consists of flat housing. Hill End is about 100.9 miles from London, making it a relatively accessible location.
Hill End and Worcestershire: where our fuel drain cover reaches
Hill End waits in the WR postcode area, and the vans that answer petrol in diesel calls there work the locations around it as well — The Vines, Droitwich Spa and Netherwich among them. Our technicians drain wherever the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the petrol pump in Hill End, right now?
No position is better: that is where you now are. Keep it off. Call.