Petrol in a Diesel Car in Doe Lea: How Worried Should You Be?
Provided it hasn't been started, worry far less than you probably are. "Have I wrecked it?" is the first question anyone in Doe Lea asks, and the truthful answer is normally no, since petrol left in a diesel tank hurts nothing till it is dragged through your fuel system — by ignition priming, by the starter, or by driving. Petrol in Diesel is who to call, with your motor kept off, so it stays that way. The remainder of this page covers 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 a second time.
Inside your engine: what petrol in a diesel does
Passing through an engine, diesel does two things at once. Oiling comes before burning; it does both. Designed to very fine gaps, the fuel injectors and your pump depend on your diesel moving through them to keep their surfaces from wearing against one another.
Poorly at the first, not at all at the second: that's petrol. It's runnier than diesel and removes the protection the system depends on, so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the knocking comes from.
Taken together, they show the shape the problem takes. The harm is done by movement, not by contact. All a tank with petrol in it amounts to is a fuel issue. The beginning of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds moves on with your fuel to the fuel injectors beyond it.
Four situations our engineers see around Doe Lea: how serious is petrol in a diesel?
Filled but not once started — as good as it gets. Just your tank has petrol in it, and so the task is emptying the tank and cleaning the fuel system where the car sits. This scenario can only truly occur on a forecourt: anywhere else, your car got there by being driven.
Your ignition turned on, or a brief start. With the fuel system primed, your lines and filter now hold petrol that has come from the tank. Drain, flush, deal with the filter: still normally easy.
Your pump has spent a couple of miles on thinned fuel — that is what driving the vehicle meant. The work is your tank, your lines, the filter and fresh fuel through the whole circuit, and how hard your car was driven matters as much as how far. Short trips, like the school run to Bramley Vale Primary & Nursery School, are one thing. Any distance on the M1, under a mile from Doe Lea, means the engine working hard throughout, and a run to Sheffield, under 15 miles away, is a very different job as well.
Driven on till it protested — rattling, smoke, a ragged idle, a soft throttle. The fuel is not behaving like diesel any more, and your motor is telling you. Leave it where it stops: a lay-by, a quiet street, the verge on Mansfield Road. What goes first is still the fuel drain and flush-through, and that deals with it, with lasting damage very rare when a vehicle is pulled over early.
Doe Lea motorists and that petrol in a diesel myths they hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A bigger tank of the same mixture is all it gives, since topping up takes out nothing. A diesel fuel system does not tolerate petrol by percentage in the way that guidance presumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. At higher pressure, through more precise components: that's how a current diesel handles its fuel, so the lubrication matters for more, not less.
The myth that catches motorists out: if it starts and drives, it must be unharmed. A petrol motor fed diesel generally won't run, and so the driver stops and the damage stops with them. Feed petrol to a diesel and it generally fires up, ticks over and pulls away as if nothing has happened — all the while its pump is wearing. A running engine doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct problem. What petrol has weakened stays thinned, and the petrol stays in the tank regardless.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol lies in the filter and lines, waiting to go straight back through the pump at the next start. Besides, petrol emptied into a can by the road is truly risky.
How does petrol in a diesel take place?
No one does it on purpose, and it's seldom carelessness. The petrol nozzle is the slimmer 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 error runs one way.
When habit and your car stop matching, it takes place. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. A rushed fill en route to Shirebrook with a train to catch. Precisely the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Passat for the first time. With rain, a call arriving, or a car full of children to deal with, your hand just does what it has always done.
Doe Lea drivers: how to avoid petrol in a diesel next time
- A green handle for unleaded and black for diesel is usual in the UK — but not on each forecourt. Go by the label on the pump, not the colour.
- The first fill in a strange motor is the time to check your filler flap — inside it, or on the cap, plenty of motors state the fuel they take.
- Good intentions do less than a sticker or a fob in a bright colour on the diesel's key when a household has one of each. So label it.
- It sounds daft and it works: on the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away then keep your mind on the petrol pump.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to block a petrol nozzle, and add-on devices are available for the rest. Treat it as a backstop, then keep reading the pump.
- Less petrol means a weaker mixture, and so stop as soon as you notice — though remembering that the next step is unchanged. It's still not to crank it.
Already put petrol in a diesel around Doe Lea?
Short and simple, then, is the order of things. Starting it is out, and so is turning on your ignition. If you are still on the forecourt — Shell or anywhere else — ask the attendants to help you push it away from the pump. What got in, roughly how much, and whether it has run: tell us that when you ring 0333 366 0103.
If it was AdBlue instead of petrol, say so. That's a different problem — corrosion and deposits instead of lost protection — and it has its own page for Doe Lea.
What makes one Doe Lea petrol in a diesel job cost more than the next
There is no fair single price for this, because the four scenarios above are four separate jobs. Which of them you are in is chiefly what shifts the cost. Where the vehicle is matters too, and whether a technician can safely get to it, after the share of petrol to what your tank takes.
Before any quote, not after, we ask three questions: your fuel that went in, the volume, and if it's run. That's why. A range turns into a straight figure when the replies are in.
About Doe Lea itself
Doe Lea is a village in Derbyshire, situated on the riverside at an elevation of 107 metres, with semi-detached housing being the predominant type of accommodation. Doe Lea lies near several other small villages, including Bramley Vale, Stockley, and Ault Hucknall, and is approximately 14.6 miles from Sheffield. Doe Lea has a population of around 691 residents, making it a small but distinct community in the East Midlands region. Doe Lea is also relatively distant from London, at a distance of 126.7 miles.
Across Derbyshire and around Doe Lea: fuel drain cover
Bramley Vale, Stockley and Ault Hucknall are among the locations near Doe Lea that the same teams work, answering petrol in diesel calls across Doe Lea's S postcode area. Our technicians drain where your car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
At the petrol pump around Doe Lea, still?
The best position there is, then — that's where you are. Keep it off. Phone.