Bilborough: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, if it has not been started. Everyone in Bilborough starts with "have I wrecked it?", and the fair answer is generally no: petrol left inside your tank of a diesel stays harmless until priming, cranking or driving pulls it into your fuel system. Petrol in Diesel is who to phone, with the motor kept off, and so it stays that way. What petrol really does to a diesel, how to gauge how far it has travelled, and how to stop it from happening again: that is the remainder of this page.
What petrol in a diesel does to the motor
On its way through a motor, diesel does two jobs. It protects first, and only then does it burn. Very fine clearances go into the injectors and the high-pressure pump, and only the diesel running through keeps those surfaces from grinding together.
Petrol does the first task poorly and the second not at all. It's runnier than diesel and removes the protection the system hinges on, and 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 opposite of what a diesel needs from its fuel. That is where the clattering comes from.
Put those together and the shape of the trouble is plain. The harm is done by movement, not by contact. A tank with petrol in it is a fuel problem. A pump that has been labouring on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Four situations our technicians see around Bilborough: how serious is petrol in a diesel?
Fuelled, and never started: nothing beats it. Being on a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol held in your tank alone, it's cleared and flushed right where it stands, and nothing more is needed.
Started for a moment, or just your ignition on. The fuel system has been bled, and so petrol has left that tank and got to the fuel filter and the lines. That's usually still a straightforward task — a drain, a flush, and the filter dealt with.
Some miles driven, and the pump has spent every one of them labouring on diluted fuel. Distance is only half of that; how hard it was driven matters just as much. Either way the work includes your tank, the lines, the fuel filter and fresh fuel through the entire system. The school run to Melbury Primary School is one matter. Very different a second time: a run to Nottingham, under 5 miles away, or any distance on the M1, under 3 miles from Bilborough, where your engine kept running hard.
Driven till it protested. Knocking, a ragged idle, smoke, a throttle that has gone soft. The engine is telling you the fuel is no longer acting like diesel. Whether it's the verge on Bracebridge Drive, a lay-by or a side street, stop there then leave it. A vehicle pulled over early very seldom has permanent damage, since the fuel drain and the flush-through, which still go first, sort it out.
What Bilborough motorists 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'll be." Nothing comes out when you top up — the tank just carries more of the same blend. Percentage isn't how a diesel fuel system copes with petrol, whatever that advice presumes.
"Modern diesels can handle a little petrol" — a myth, and nearer the reverse. A current diesel runs its fuel through finer components at higher pressure, which makes the protection matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there is no harm done." The motorist of a petrol motor fed diesel normally has no choice but to stop, since it will not run, and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile the pump wears. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an old workaround for a separate problem. What petrol has thinned remains weakened, and that petrol remains inside your tank anyway.
Myth: "Drain your tank yourself and you are sorted." Once the engine has been run, some of that petrol is no longer inside the tank: it is in the fuel filter and your lines, and it goes right back through your pump at your next start. It is also genuinely dangerous to drain petrol into a can at the roadside.
How petrol ends up: petrol in a diesel
A careless moment is seldom the cause, and no one means to do it. The petrol nozzle is the smaller 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 slip runs one way.
It occurs when habit and your car stop matching. Courtesy car, hire car, or a vehicle that is brand new. Households running one of each, petrol and diesel. Your usual forecourt, its pumps now in a different order. A train to catch, and a rushed fill on the way to Bulwell. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it happens. The hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel at your next fill-up in Bilborough
- The label is what matters, so read the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- Plenty of cars state the fuel type inside the filler flap or on the cap, and so check it on your first fill in any motor you don't know.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, in a house with one of each.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car needs its first tank. It sounds silly. It does the trick.
- Mistakes like this are simple to make while your mind is on something else, so your phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to refuse a petrol nozzle, and add-on devices exist for vehicles without one. They are a backstop, not a reason to stop checking the pump.
- Less petrol means a thinner mixture, and so stop the moment you realise — though remembering that your next stage is unchanged. It is still not to fire it up.
Bilborough: already put petrol in a diesel?
Then the order of things is short. Do not turn your ignition on, and don't crank it. If you are still at the forecourt — Asda or anywhere else — ask the attendants to help you push the vehicle clear of the pump. What went in, roughly how much, and if it has run: tell us those when you ring 0333 366 0103.
If it was AdBlue and not petrol, say so. That is a different issue — corrosion and deposits instead of lost protection — and it has its own page for Bilborough.
Bilborough petrol in a diesel tasks: why one costs more than another
The four scenarios above are four separate jobs, so no single quote for this would be fair. Which of them you're in is mostly what moves your cost. Beyond that it's the ratio — how much petrol was put in against how much your tank holds — and then where your car is and whether a van can get to it safely.
What went in, how much, and whether it's run — three questions our technicians ask before costing, not after, for precisely that reason. Those answers turn a range into a straight figure.
About Bilborough, briefly
Bilborough is a suburban area located in Nottinghamshire, England, with a population of around 5418 people, and is situated approximately 3.3 miles from Nottingham. Bilborough sits at an elevation of 75 metres, in a gently sloping inland area, and is characterised by its predominantly semi-detached housing stock. Bilborough is close to nearby places such as Strelley, Beechdale, and Wollaton, and is part of the wider Nottingham urban area. Bilborough is also within commuting distance of major cities, with London being around 110.9 miles away.
Fuel drain cover around Bilborough and across Nottinghamshire
Petrol in diesel calls in Bilborough — part of the NG postcode area — go to vans that likewise cover the places about it, Strelley, Beechdale and Wollaton included. Our engineers drain where your car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the petrol pump around Bilborough?
No position is better: that's where you now are. Call, and leave it turned off.