Oving: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less worried than you probably are. Until your ignition primes your pump, the starter cranks, or the car is driven, petrol in a diesel tank just waits there and does nothing. Which makes the honest reply to the first Oving question — "have I wrecked it?" — usually no. Keep it that way: leave your engine off then call Petrol in Diesel. The rest of this page sets out what petrol really does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
Petrol in a diesel: what does it do to your engine?
On its way through an engine, diesel has two tasks. It burns, and before it burns it protects. What stops the surfaces inside your high-pressure pump and the fuel injectors from grinding against each other is the diesel flowing through them — they're built to extremely fine clearances.
Of those two jobs, petrol handles the first badly and the second never. The clattering comes from petrol being designed not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication the system rests on, and any pump running on such a blend is wearing itself.
Together, those leave the shape of the issue plain. Contact does not do the harm — movement does. Where that petrol is only in your tank, it's a fault of fuel, nothing more. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to your injectors further on.
Petrol in a diesel around Oving: how bad is it? Four cases
Fuelled but not once started — the best it gets. Just that tank has petrol in it, and so the job is clearing your tank and flushing the fuel system where the vehicle sits. This scenario can only truly occur on a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a second. Once primed, your system has drawn petrol out of that tank as far as the filter and your lines. That's usually still a straightforward job — a drain, a flush, and the filter seen to.
A couple of miles driven, and the pump has spent every one of them running on diluted fuel. The work is the tank, your lines, the filter and clean fuel through the entire circuit, and how hard the vehicle was driven counts as much as how far. Driving the kids to Tangmere Primary Academy is one kind of trip. Any mileage on the A3(M), under 15 miles from Oving, means the motor has worked hard throughout, and a run to Chichester, under 3 miles away, is a very different task too.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone uneven. The fuel is not acting like diesel any more, and your motor is saying so. Leave it wherever it has stopped: a lay-by, a side street, the verge on High Street. A vehicle pulled over early very seldom has permanent damage, as the drain and the flush-through, which still come first, sort it out.
Oving motorists and the 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 won't. A fuller tank of the same mix is all it gives, because topping up takes out nothing. That guidance supposes a diesel fuel system tolerates petrol by percentage. It does not.
If anything, the opposite holds. Myth: "A newer diesel can cope with a bit of petrol." At higher pressure, through finer parts: that's how a modern diesel moves its fuel, and so the protection counts for more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up most drivers than any other. The motorist of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the harm stops with them. Whilst the pump wears, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. Fine and running are not the same thing.
An outdated fix for a different problem is behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has diluted stays weakened, and the petrol remains inside your tank regardless.
Once the motor has been run, part of the petrol sits in the fuel filter and your lines, not the tank — and the next start pulls it straight back through the pump. So the myth "drain the tank yourself and you're sorted" does not stand up. Also, a can of petrol drained by the kerbside is genuinely hazardous.
Why petrol in a diesel occurs at all
Carelessness is rarely the cause, and nobody means to do it. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol motor at all. The forecourt makes it easy, and the slip runs one way.
Routine and your car getting out of step is how it happens. Any motor that's new to you — hired, on loan as a courtesy car, or brand new. Two vehicles on one drive, one petrol, one diesel. Your normal forecourt, its pumps now in a different order. A train to catch, and a hurried fill on the way to Chichester. Years of petrol motors behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that's when. Throw in rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
Preventing petrol in a diesel next time you fill up in Oving
- The label is what matters, and so read the petrol pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- Plenty of cars state the fuel type inside your filler flap or on the cap, so check there on the first fill in a car you don't know.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, in a house with one of each.
- Before the nozzle comes off the pump the first time you fuel a hired or new motor, say "diesel" aloud. Silly, perhaps, but it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck the phone away and keep your mind on the petrol pump.
- Add-on devices are available for cars without one, and some diesels are built with a filler that will not accept a petrol nozzle. Useful — but a backstop only, never a reason to stop checking the label.
- The moment you realise, stop: less petrol inside the tank makes a weaker blend. What to do next doesn't change, though — still do not start the vehicle.
Petrol already in a diesel in Oving? Begin here
In that case, there is only a short order of things. Leave it unstarted, with your ignition switched off too. The attendants on the forecourt — whether at Esso itself or wherever you filled up — will usually help push it clear of the petrol pump if you ask. Ring 0333 366 0103 next, with three facts — the fuel, the approximate amount, and if it's run.
Corrosion and deposits are the problem with AdBlue, whereas petrol brings lost lubrication. So if it was AdBlue, say so — and see its own Oving page.
Why one petrol in a diesel task in Oving costs more than another
Four different jobs lie behind the four situations above — which is why there is no honest single quote. What moves the cost is chiefly which of them you're in. The ratio counts next, meaning how much of that tank is petrol, followed by the position of your car and whether reaching it is safe for a van.
Ahead of any quote, not after, we ask three questions: your fuel that got in, its quantity, and whether it has run. That is why. Given the answers, you get a straight figure instead of a range.
About Oving, briefly
Oving is a village in West Sussex, situated on the banks of the River Lavant, with an elevation of around 11 metres above sea level. Oving lies close to the city of Chichester, approximately 2.5 miles away, and is near other villages such as Shopwyke, Tangmere, and Merston. Oving has a population of around 902 people and predominantly consists of semi-detached housing. Oving is located within the South East region, about 53 miles from London.
Oving and West Sussex: where our fuel drain cover runs
Petrol in diesel call-outs in Oving — part of the PO postcode area — go to teams that also cover the locations around it, Shopwyke, Tangmere and Merston included. A forecourt, a supermarket car park, a lay-by or your own driveway are all places we drain, and the car does not need to move to us.
Still at the petrol pump in Oving?
Then, you could not be in a better place. Turned off it remains; then phone.