Should You Worry? Petrol in a Diesel Car in Bathpool
Not started? Then less worried than you likely feel. Everyone in Bathpool begins with "have I wrecked it?", and the fair answer is normally no: petrol left inside that tank of any diesel remains harmless until priming, cranking or driving pulls it into the system. To leave it like that, ring Petrol in Diesel and leave your engine switched off. 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 a second time.
Inside the engine: what petrol in a diesel does
On its way through a motor, diesel does two jobs. It protects to begin with, and after that does it burn. Made to very fine gaps, the fuel injectors and the pump depend on your diesel flowing through them to keep their surfaces from wearing against one another.
Petrol handles the first task badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump on that mixture to wear itself. It is equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the knocking.
The shape of the trouble is clear once you put those together. Not contact but circulation is what causes the harm. All a tank with petrol in it amounts to is a fuel issue. Whatever a worn pump sheds travels on, carried by your fuel, into the fuel injectors further along, which is why a pump that has been working on the petrol is where a mechanical problem begins.
How serious is petrol in a diesel? Four scenarios our technicians see in Bathpool
Filled but not once started — the best it gets. At a forecourt, and truly only there, that petrol is still limited to your tank — since everywhere else your car was driven to get to it. The task is emptying and rinsing on the spot.
Your ignition switched on, or a short start. With the system primed, the fuel lines and filter now contain petrol that has come from that tank. That is usually still a straightforward job — a drain, a flush, and the fuel filter dealt with.
A few miles driven, and the pump has spent each of them running on weakened fuel. The work is your tank, the fuel lines, the filter and fresh fuel through the entire circuit, and how hard your car was driven matters as much as how far. Short trips, like the school run to West Monkton Church of England School, are one matter. A run as far as Wells, under 25 miles away, is a very different job. So is any distance on the M5, under a mile from Bathpool, where the motor has been labouring hard the whole time.
Rattling, an uneven idle, smoke, a throttle gone soft: driven till it complained. The fuel is not behaving like diesel any more, and your engine is saying so. Stop wherever you are — the verge on St Quintin Park, a lay-by, a side street — and leave it there. What goes first is still the drain and flush, and that deals with it, with permanent damage very unusual when a car is stopped early.
Myths Bathpool motorists hear about petrol in a diesel
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 — that tank just carries more of the same mixture. That guidance supposes a diesel fuel system handles petrol by percentage. It doesn't.
"Newer diesels can handle a little petrol" — a myth, and nearer the opposite. At higher pressure, through more precise parts: that's how a current diesel moves its fuel, so the protection matters for more, not less.
One myth that catches motorists off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it usually won't run, so the driver stops — and the harm stops with them. Whilst the pump wears, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. Being able to run isn't the same as being fine.
Not so: a two-stroke additive lets you to drive home. It is an old fix, supposed for another problem. None of what petrol weakened gets put back by it — and later, your tank still contains that petrol.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol sits in the fuel filter and lines, ready to go straight back through your pump at the next start. Emptying petrol into a can at the roadside is also really hazardous.
How does petrol in a diesel occur?
It's seldom carelessness, and nobody does it on purpose. One way only, because of the nozzles: the smaller petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one mostly will not fit a petrol motor. That's how the forecourt makes it straightforward.
It happens when routine and your car stop matching. Any motor that is new to you — hired, on loan as a courtesy car, or just bought. A household with one petrol and one diesel on the drive. Your normal forecourt, its pumps now in a different order. Fuelling up in a rush on the way to Taunton, with a train to catch. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
How to prevent petrol in a diesel at your next fill-up around Bathpool
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Read the petrol pump's label; the colour is only a clue.
- Check the filler flap. Many cars state the fuel type inside the flap or on the cap. Look at it on your first fill in a car you don't know.
- A coloured fob or a sticker on your 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.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away and keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to reject a petrol nozzle, and add-on devices are available for motors without one. They are a safety net, not a reason to stop reading the pump.
- Less petrol means a weaker blend, and so stop as soon as you notice — though remembering that the next stage is unchanged. It's still not to crank it.
Bathpool: already put petrol in a diesel?
Short and simple, then, is the order of things. Do not switch the ignition on, and don't fire it up. Yet on the forecourt, at Sainsbury's or anywhere else? Ask the attendants to help you roll it away from the pump. What got in, about how much, and if it has run: tell us those when you phone 0333 366 0103.
Say so if it was AdBlue rather than petrol: it is a different problem, with its own page for Bathpool, because AdBlue brings corrosion and deposits rather than lost protection.
What makes one Bathpool petrol in a diesel job cost more than the next
Four different jobs sit behind the four scenarios above — which is why there is no fair single price. The situation itself does most of the work of moving the cost. Two things come after that: the petrol that was put in as a share of what your tank takes, then the place your car is in and whether our van can get to it safely.
Before any quote, not after, come three queries: your fuel that got in, its volume, and if it has run. That's why. Those replies are what change a range into one firm number.
About Bathpool, briefly
Bathpool is a village in Somerset, situated on the riverside at a low elevation of around 14 metres. Bathpool lies near several other small settlements, including Maidenbrook, Halcon, and Monkton Heathfield, and is approximately 22 miles from the city of Wells. Bathpool has a population of around 863 people, predominantly living in detached houses. Bathpool is also within commuting distance of larger cities, being around 131 miles from London.
Bathpool and Somerset: where our fuel drain cover reaches
Maidenbrook, Halcon and Monkton Heathfield are among the places near Bathpool that the same vans work, answering petrol in diesel calls across Bathpool's TA postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our engineers drain, and the vehicle does not need to come to us.
Still at the pump in Bathpool?
No position is better: that is where you now are. Turned off it stays; then ring.