How Worried Should You Be? Petrol in a Diesel Car in Balls Hill
Not started? Then less worried than you likely feel. Petrol resting in a diesel tank does nothing to your motor until something draws it through the system — your ignition priming the pump, the starter, or driving on its own. So the truthful answer to the first query anyone around Balls Hill asks, "have I ruined it?", is normally no. Petrol in Diesel is who to call, with your engine left off, so it remains that way. Further down, this page sets out what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Inside the motor: what petrol in a diesel really does
On its way through an engine, diesel does two jobs. It protects first, and after that does it burn. What keeps the surfaces inside your high-pressure pump and the injectors from wearing against each other is the diesel passing through them — they are made to extremely fine clearances.
The second job petrol does not do at all, and the first it does poorly. The knocking 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 thinner than diesel, it strips out the protection the system rests on, and any pump working on such a mix is wearing itself.
Put these together and the shape of the problem is clear. The damage is done by movement, not by contact. Petrol in a tank is a fuel problem. Whatever a worn pump sheds travels on, borne by your fuel, into your injectors downstream, which is why a pump that has worked on that petrol is where a mechanical fault starts.
How serious is petrol in a diesel? Four scenarios our technicians see in Balls Hill
The best case there can be: filled up, never started. That petrol is inside the tank and just that tank, and the task is a drain and a flush where the vehicle sits. This is the one scenario that can only really occur at a forecourt, since anywhere else the vehicle has been driven to get there.
Started for a second, or only your ignition on. Once primed, the fuel system has pulled petrol from your tank as far as the filter and your lines. That is generally still a simple job — a drain, a flush, and the fuel filter seen to.
Driven a couple of miles. Now the pump has spent these miles running on weakened fuel. The work is that tank, your lines, the fuel filter and clean fuel through the whole circuit, and how hard your car was driven matters as much as how far. Driving the children to Moorlands Primary School is one kind of trip. Very different once more: a run to Wolverhampton, under 10 miles away, or some distance on the M6, under 3 miles from Balls Hill, where your engine kept working hard.
It protested, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone lumpy. The fuel is not acting like diesel any more, and your engine is saying so. Pull up wherever you are — the verge on Tame Crossing, a lay-by, a side street — then leave the car there. The fuel drain and flush-through still come first, and they sort it out: if a car is pulled over early, permanent damage is very rare.
What Balls Hill people 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 will be." A fuller tank of the same mix is all it gives, because topping up removes nothing. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance assumes.
Not so: a newer diesel copes with a bit of petrol. Rather, the opposite. At higher pressure, through more precise parts: that is how a modern diesel handles its fuel, and so the protection counts for more, not less.
One myth that catches people out: if it starts and drives, it must be unharmed. Any petrol engine fed diesel normally won't run, so the motorist stops and the harm stops with them. Feed petrol to a diesel and it generally fires up, idles and pulls away like nothing has happened — all the while its pump wears. Fine and running are not the same at all.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different fault. What petrol has diluted stays diluted, and that petrol stays inside that tank anyway.
"Drain it yourself and you are sorted" — a myth, since after it's been running some petrol sits in the fuel filter and lines, ready to go straight back through your pump at the next start. And, a can of petrol drained at the kerbside is genuinely hazardous.
How does petrol in a diesel happen?
It's rarely carelessness, and no one does it on purpose. A diesel nozzle mostly will not fit a petrol vehicle, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and just in one direction.
It happens when habit and the vehicle stop matching. A motor that's new to you — a hire car, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the drive. A familiar forecourt with the pumps in a different order. Fuelling up in a hurry en route to Bescot Stadium, with a train to catch. Years of petrol motors behind you, a diesel Volkswagen Passat in front of you on the forecourt for its first tank — that is when. Add rain, a phone call or a back seat full of children, and the hand does what it has always done.
Next time you fill up in Balls Hill: avoiding petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, but not on every forecourt. The label is what matters.
- Check your filler flap. Many motors state the fuel type inside the flap or on the cap. Look at it on your first fill in a motor you don't know.
- One of each in the house? Label the key to the diesel — a coloured fob, a sticker — because meaning to remember isn't enough.
- "Diesel", aloud, before you lift the nozzle — every time a new or hired car needs its first tank. It sounds daft. It works.
- While you are thinking about something else, this is an easy mistake to make — so tuck your phone 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 checking the pump.
- Less petrol makes a thinner mix, so stop the moment you realise — though remembering that the next stage is unchanged. It is still not to crank it.
Put petrol in a diesel around Balls Hill already?
In that case, there's just a short order of things. Starting it is out, and so is switching on your ignition. If you're still at the forecourt — Esso or anywhere else — ask the staff to help you roll it away from the pump. Next, 0333 366 0103. We will ask what got in, roughly how much, and if it's been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different issue — Balls Hill has a page just for it.
Balls Hill petrol in a diesel tasks: why one costs more than another
There's no honest single quote for this, because the four scenarios above are four separate tasks. What shifts the cost is chiefly which of them you are in. Two things come after that: the petrol that went in as a share of what your tank holds, then the place your car is in and whether our van can reach it safely.
Before any quote, not after, we ask three queries: your fuel that got in, its quantity, and if it has run. That's why. A range becomes a straight figure once the answers are in.
About Balls Hill and where it is
Balls Hill is a suburban area situated near the lakeside in the West Midlands, with an elevation of around 129 metres. Balls Hill lies approximately 5.7 miles from Wolverhampton and 107.5 miles from London, placing it in a commuter belt with access to major cities. Balls Hill is characterised by its semi-detached housing stock and proximity to nearby places such as Hill Top and Wednesbury. Balls Hill has a population of around 7244 residents.
Across West Midlands and around Balls Hill: fuel drain cover
Hill Top, Mesty Croft and Wednesbury are among the locations near Balls Hill that the same vans work, answering petrol in diesel jobs across Balls Hill's WS postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots we drain, and your vehicle does not need to come to us.
Still at the pump around Balls Hill?
The best position there is, then — that's where you are. Switched off it stays; then phone.