Should You Worry? Petrol in a Diesel Car in County Oak
Provided it has not been started, worry far less than you probably are. Petrol sitting in a diesel tank does nothing to the engine until something draws it through the fuel system — your ignition priming the pump, the starter, or the drive itself. So the fair answer to the first question everyone in County Oak asks, "have I wrecked it?", is generally no. Keep it like that: leave your engine off and phone Petrol in Diesel. Further down, you will find what petrol really does inside a diesel, how far it might have gone, and how to stop it happening to you a second time.
Inside the motor: what petrol in a diesel does
On its way through a motor, diesel has two jobs. Before it ignites, it lubricates — and then it ignites. The high-pressure fuel pump and the injectors are made to very fine gaps, and your diesel passing through them is what keeps those surfaces from wearing against each other.
Badly at the first, not at all at the second: that is petrol. A pump running on a petrol mixture is wearing itself out, because petrol is runnier than diesel and takes away the lubrication the fuel system relies on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that is where the clattering comes.
Together, those leave the shape of the trouble plain. The harm is done by movement, not by contact. All a tank with petrol in it amounts to is a fuel fault. Once your pump has been labouring on that petrol, a mechanical fault has begun: whatever is shed by a pump that is grinding travels downstream to the injectors with your fuel.
Petrol in a diesel around County Oak: how serious is it? Four cases
Filled up, and never started: nothing beats it. Just your tank has petrol in it, so the job is emptying your tank and cleaning your system where the car stands. This scenario can only truly occur at a forecourt: anywhere else, the car got there by being driven.
Your ignition switched on, or a short start. With the system primed, the lines and filter now contain petrol that has come from the tank. That is generally still a straightforward task — a drain, a flush, and the filter dealt with.
Those few miles on the road meant your pump running on fuel weakened by petrol throughout. How hard the car was driven counts as much as how far, and this work takes in the tank, the fuel lines, your filter and clean fuel through the whole circuit. Short trips, like the school run to Langley Green Primary, are one thing. A run as far as Brighton and Hove, under 25 miles away, is a very different task. So is any miles on the M23, under 3 miles from County Oak, where your engine has been labouring hard throughout.
Rattling, an uneven idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you the fuel is no longer behaving like diesel. Pull up wherever you are — the verge on Fleming Way, a lay-by, a side street — then leave the vehicle where it is. What comes first is still the drain and flush-through, and that deals with it, with lasting damage very uncommon when a car is stopped soon.
What County Oak motorists get told about petrol in a diesel — and the myths in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Topping up takes out nothing; it gives you a fuller tank of the same mix. That advice supposes a diesel fuel system tolerates petrol by percentage. It does not.
Not so: a modern diesel copes with a bit of petrol. Rather, the opposite. Lubrication counts more on modern diesels, not less, since their fuel runs through more precise components at higher pressure.
Myth: "If it starts and drives, there's no damage done." This is the one that catches motorists. Diesel in a petrol motor usually means a motor that will not run: the motorist stops, and so does the damage. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile your pump grinds. Running isn't 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 problem. What petrol has weakened stays diluted, and that petrol stays in your tank anyway.
The next start sends petrol back round your pump from the fuel lines and the filter, where some of that ends up once the engine has run. That's why a DIY tank drain does not sort it — a myth. On top of that, petrol drained into a can by the road is truly dangerous.
How it happens: petrol in a diesel
No one does it on purpose, and it's rarely carelessness. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle mostly won't go into a petrol vehicle at all. So the error runs one way.
Habit and the car falling out of step is how it happens. A motor that is new to you — hired, on loan as a courtesy car, or just bought. A household with one petrol and one diesel on the drive. The pumps in a different order on a well-known forecourt. Racing for a train at Crawley and filling up en route. The first fill-up in a diesel Renault Megane after years of driving petrol is precisely the moment it happens. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
Next time you fill up around County Oak: preventing petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Check the petrol pump's label; the colour is just a clue.
- Inspect the filler flap. Plenty of cars state the fuel inside the flap or on the cap. Look at it on the first fill in a vehicle you do not know.
- A coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember, in a house with one of each.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. It sounds silly 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.
- Add-on devices are available for vehicles without one, and some diesels come with a filler that will not take a petrol nozzle. Helpful — but a backstop only, never a reason to stop checking the label.
- Less petrol makes a thinner blend, and so stop the moment you realise — though remembering that the next step is unchanged. It is still not to start it.
Petrol already in a diesel around County Oak? Start here
The order of things is brief, then. Do not switch your ignition on, and do not fire it up. Ask the attendants to help you roll it away from the pump if you are still on the forecourt, whether that's BP or anywhere else. Then call 0333 366 0103 and tell us what got in, roughly how much, and if it has run.
Say so if it was AdBlue rather than petrol: it is a different problem, with its own page for County Oak, since AdBlue brings corrosion and deposits instead of lost protection.
County Oak petrol in a diesel tasks: why one costs more than another
The four scenarios above are four separate jobs, so no single price for this would be fair. What shifts the cost is chiefly which of them you are in. Two things follow that: the petrol that was put in as a share of what your tank takes, then the place the vehicle is in and whether a technician can reach it safely.
That's why our engineers ask three queries before costing instead of after: what was put in, how much, and if it has run. Those replies are what change a range into one firm number.
About County Oak
County Oak is a suburban area in West Sussex, situated inland at an elevation of 66 metres, and forms part of the wider Crawley urban area. County Oak is located near several other suburban areas, including Lowfield Heath, Manor Royal, and Langley Green. County Oak has a population of approximately 972 residents, who mostly live in terraced housing. County Oak is also within commuting distance of London, being around 25.9 miles from the capital, and 21.6 miles from the city of Brighton and Hove.
Fuel drain cover across West Sussex, County Oak included
Lowfield Heath, Manor Royal and Langley Green are among the places around County Oak that the same vans work, answering petrol in diesel calls across County Oak's RH postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots we work, and the vehicle does not need to move to us.
In County Oak and still at the petrol pump?
No position is better: that is where you are. Ring, and keep it switched off.