Should You Worry? Petrol in a Diesel Car in Kessingland
If it hasn't been started, you can worry far less than you probably are. Everyone in Kessingland begins with "have I wrecked it?", and the honest answer is normally no: petrol resting in that tank of a diesel stays harmless till priming, cranking or driving draws it into the fuel system. Petrol in Diesel is who to ring, with the engine kept off, so it remains that way. The remainder 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 does not happen to you again.
Your engine and petrol in a diesel: what goes on
On its way through an engine, diesel has two jobs. It lubricates to begin with, and after that does it burn. What stops the surfaces inside the high-pressure fuel pump and your injectors from wearing down against each other is your diesel passing through them — they are designed to extremely fine clearances.
The second job petrol does not do at all, and the first it does badly. It is runnier than diesel and removes the lubrication the system depends on, and so a pump running on a petrol mixture 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's where the knocking comes from.
Put those together and the shape of the trouble is plain. It is movement that causes the harm, not contact. Where the petrol is only inside your tank, it's an issue of fuel, nothing more. Once the pump has been working on that petrol, a mechanical issue has started: whatever is shed by a pump that's wearing is carried onward to your injectors with your fuel.
Four scenarios we see around Kessingland: how bad is petrol in a diesel?
Filled but not once started — the best it gets. On a forecourt, and truly only there, that petrol is still confined to that tank — since anywhere else the car was driven to get to it. The job is emptying and flushing on the spot.
Started for a second, or only the ignition on. With the fuel system primed, the fuel lines and filter now contain petrol that has come from that tank. Usually little more than clearing, purging and seeing to the fuel filter, and so still easy.
Those few miles on the road meant your pump working on fuel thinned by petrol throughout. Miles is only half of it; how hard it was driven counts just as much. Either way the work includes your tank, the fuel lines, your filter and clean fuel through the whole system. The school run to Kessingland Church of England Primary Academy is one matter. Getting as far as Norwich, under 25 miles away, makes a very different job — as does any distance on the M11, over 50 miles from Kessingland, with the motor working hard all the way.
Knocking, an uneven idle, smoke, a throttle gone soft: driven until it complained. What you are hearing is the motor signalling fuel that no longer runs like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on High Street. Permanent damage is very unusual if a vehicle is stopped quickly, and the fuel drain and flush that still come first sort it out.
Kessingland people and that petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing comes out when you top up — the tank just holds more of the same blend. The assumption behind the guidance — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the reverse. A modern diesel runs its fuel through smaller parts at higher pressure, which makes the lubrication count more, not less.
The myth that catches people off guard: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile your pump wears. Being able to run isn't proof of being fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct issue. It doesn't put back what petrol has weakened, and that petrol is still inside that tank after that.
The next start draws petrol back round the pump out of your lines and the fuel filter, where some of that ends up once the engine has run. That's why a DIY tank drain does not leave you sorted — a myth. Besides, petrol emptied into a can by the road is genuinely dangerous.
How does petrol in a diesel happen?
It is rarely carelessness, and no one does it on purpose. A diesel nozzle generally will not fit a petrol vehicle, yet the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and only in one direction.
When routine and your car stop matching, it happens. Courtesy car, hire car, or a vehicle that is new. A household with one petrol and one diesel on the driveway. The pumps in a different order on a familiar forecourt. A hurried fill en route to Oulton Broad South with a train to catch. The first fill-up in a diesel Volkswagen Passat after years of driving petrol is precisely the moment it takes place. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
How to avoid petrol in a diesel at your next fill-up in Kessingland
- Check the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what counts.
- In a vehicle you don't know, look inside the flap over your filler or at the cap before the first fill: many cars state the fuel type there.
- One of each in the home? Mark your key to your diesel — a bright fob, a sticker — because intending to remember is not enough.
- It sounds daft and it works: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- Put your phone away. This is an easy mistake to make whilst you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to reject a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop checking the pump.
- Less petrol makes a weaker blend, and so stop as soon as you realise — though remembering that your next step is unchanged. It's still not to start the car.
Kessingland: already put petrol in a diesel?
In that case, there is just a short order of things. Starting it is out, and so is switching on the ignition. Yet on the forecourt, at Harvest Energy or anywhere else? Ask the staff to help you roll the vehicle clear of the petrol pump. Then call 0333 366 0103 and tell us what went in, roughly how much, and if it has run.
Say so if it was AdBlue rather than petrol: it's a separate fault, with its own page for Kessingland, because AdBlue brings corrosion and deposits instead of lost protection.
One petrol in a diesel task around Kessingland costs more than another. Why?
There is no fair single quote for this, since the four situations above are four separate jobs. Which of them you're in is chiefly what shifts your cost. The ratio matters next, meaning how much of your tank is petrol, and then the location of the vehicle and whether reaching it is safe for our van.
That is why we ask three queries before pricing rather than after: what got in, how much, and whether it's run. Their replies are what change a range into one firm number.
About Kessingland and where it is
Kessingland is a coastal village in Suffolk, situated near the Norfolk border, with Kessingland Beach forming part of its shoreline. Kessingland has a population of around 2285 people, living in predominantly semi-detached housing, and is located approximately 20 metres above sea level. Kessingland is close to nearby places such as Black Street and Gisleham, and is within commuting distance of Norwich, the nearest city. Kessingland is also around 100 miles from London, making it a popular choice for those who want to escape the city.
Fuel drain cover across Suffolk, Kessingland included
Kessingland sits in the NR postcode area, and the teams that answer petrol in diesel jobs there work the spots around it as well — Black Street, Kessingland Beach and Gisleham among them. A forecourt, a supermarket car park, a lay-by or your own drive are all places our engineers drain, and the vehicle doesn't need to come to us.
Still at the pump in Kessingland?
No position is better: that is where you are. Keep it off. Phone.