Petrol in a Diesel Car in Oakley: How Worried Should You Be?
Probably less than you already are — provided no one has started the car. Until the ignition primes the pump, your starter turns, or your car is driven, petrol in a diesel tank simply waits there and does nothing. Which means the honest reply to the first Oakley question — "have I wrecked it?" — normally no. Keep it that way: leave the engine off and call Petrol in Diesel. The rest of this page explains what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you again.
What petrol in a diesel does to the engine
Passing through an engine, diesel is doing two things at the same time. Before it combusts, it lubricates — and then it combusts. Your high-pressure pump and the fuel injectors are built to extremely fine tolerances, and the diesel passing through them is what keeps those surfaces from wearing against one another.
Of those two jobs, petrol manages the first badly and the second never. It is thinner than diesel and strips away the protection your fuel system rests on, and so a pump running on a petrol mix is a pump wearing itself. And petrol is made to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the knocking comes from.
Seen together, they make clear what shape the issue has. Contact doesn't do the damage — movement does. All a tank with petrol in it amounts to is a fuel problem. A pump that has been running on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with the fuel to your injectors further on.
Oakley, petrol in a diesel: four situations, from mild to significant
Filled up, and not started: no case is better. The petrol is in that tank and only the tank, and the job is a drain and a flush where the vehicle stands. This is the one situation that can only really happen at a forecourt, as anywhere else the vehicle has been driven to get there.
The ignition switched on, or a short start. Once primed, the fuel system has pulled petrol from that tank up to the fuel filter and the lines. Drain, flush, deal with your filter: still usually simple.
Driven a few miles. Now your pump has spent these miles running on diluted fuel. Tank, lines, filter, then fresh fuel put through the whole circuit: that's this work, and the way the vehicle was driven matters as much as the mileage. On the school run to Scole Church of England Primary Academy, the mileage is small. A run as far as Norwich, under 25 miles away, is a very different job. So is any miles on the M11, under 50 miles from Oakley, where the motor has been labouring hard throughout.
It protested, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. The motor is telling you your fuel is no longer behaving like diesel. Leave it wherever it stops: a lay-by, a quiet street, the verge on Oakley Church Lane. A vehicle stopped early very seldom has long-term damage, because the fuel drain and the flush, which still come first, deal with it.
What Oakley motorists get told about petrol in a diesel — and the myths in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A bigger tank of the same mix is all you get, since topping up takes out nothing. The idea behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the reverse holds. Myth: "A modern diesel can cope with a bit of petrol." Lubrication counts more on modern diesels, not less, because their fuel passes through smaller parts at higher pressure.
One myth that catches drivers off guard: if it starts and drives, it must be unharmed. Diesel in a petrol motor generally means a motor that won't run: the driver stops, and so does the harm. A diesel fed petrol generally starts, idles and drives away as if nothing has happened, whilst your pump wears. Being able to run isn't proof of being fine.
Myth: "Add some two-stroke oil and drive it home." It's an outdated workaround for a different fault. What petrol has diluted stays diluted, and that petrol remains inside your tank regardless.
The next start draws petrol back round your pump from the fuel lines and the fuel filter, where some of that sits once the engine has been run. That's why a DIY tank drain does not sort it — a myth. It is also really dangerous to drain petrol into a can by the roadside.
Why petrol in a diesel takes place so easily
It's seldom carelessness, and no one does it on purpose. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol car at all. The forecourt makes it easy, and the slip runs one way.
When habit and the vehicle stop matching, it takes place. Any vehicle that's new to you — hired, on loan as a courtesy car, or just bought. One petrol and one diesel on the driveway of the same household. A familiar forecourt with the pumps in a different order. Racing for a train outside Diss and fuelling up en route. A new-to-you diesel Volkswagen Passat, its first fuelling, and a motorist used to petrol: exactly when it occurs. The hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
Avoiding petrol in a diesel next time you fill up around Oakley
- The label is what matters, and so check the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, yet not on every forecourt.
- In a vehicle you don't know, look inside the flap over the filler or at the cap before the first fill: plenty of motors state the fuel type there.
- Good intentions do less than a sticker or a fob in a bright colour on your diesel's key when a home has one of each. So mark it.
- It seems daft and it does the trick: on the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump.
- Mistakes like this are easy to make while your mind is on something else, so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop reading the petrol pump.
- Spotting it halfway? Stop at once. A thinner mix results from less petrol in your tank, but the next stage stays the same: don't start the vehicle.
Petrol already in a diesel in Oakley? Start here
In that case, there is just a short order of things. Leave it unstarted, with your ignition switched off as well. The staff on the forecourt — whether at BP itself or wherever you filled up — will usually help roll it away from the pump if you ask. What went in, about how much, and if it's run: tell us those when you phone 0333 366 0103.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different fault — Oakley has a page all for it.
Why one petrol in a diesel job around Oakley costs more than another
There is no honest single price for this, since the four situations above are four different tasks. Which of them you are in is chiefly what moves your cost. Two things follow that: the petrol that was put in as a share of what that tank takes, then the spot the car is in and whether a technician can get to it safely.
Before any quote, not after, come three queries: the fuel that was put in, its quantity, and whether it has run. That is why. The answers change a range into a straight figure.
About Oakley and its setting
Oakley is a small village in Suffolk, situated on the riverside at an elevation of around 35 metres. Oakley lies near the villages of Brome Street and Billingford, and is close to Oakley Park. Oakley has a population of approximately 562 people, predominantly living in detached houses. Oakley is located near the city of Norwich, about 19.9 miles away, and is around 80.5 miles from London.
Across Suffolk and in Oakley: fuel drain cover
Oakley waits in the IP postcode area, and the teams that answer petrol in diesel jobs there work the locations around it as well — Brome Street, Oakley Park and Billingford among them. Our technicians drain where your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the petrol pump in Oakley, still?
The best place there is, then — that's where you are. Keep it off. Ring.