How Worried Should You Be? Petrol in a Diesel Car in Middle Deal
Far less than you likely are, provided it hasn't been started. Until your ignition primes the pump, the starter turns, or your vehicle is driven, petrol in a diesel tank just waits there and does nothing. Which means the truthful reply to the first Middle Deal question — "have I ruined it?" — usually no. Petrol in Diesel is who to phone, with your engine left off, and so it remains that way. Further down, this page sets out what petrol really does inside a diesel, how far it might have gone, and how to stop it happening to you a second time.
The motor and petrol in a diesel: what happens
On its way through an engine, diesel does two jobs. Before it ignites, it lubricates — then it combusts. Very fine gaps are built into the fuel injectors and the high-pressure fuel pump, and only the diesel running through stops those surfaces grinding together.
Petrol handles the first job badly and the second not at all. The knocking comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips away the protection your system hinges on, and any pump running on that blend is wearing itself.
The shape of the problem is plain once you put those together. Not contact but movement is what does the damage. All a tank with petrol in it amounts to is a fuel problem. Whatever a worn pump sheds travels on, carried by the fuel, into your injectors further along, which is why a pump that has worked on the petrol is where a mechanical fault starts.
Petrol in a diesel around Middle Deal: how serious is it? Four situations
The best case there can be: filled up, not once started. The petrol is inside that tank and only your tank, and the job is a drain and a flush where the vehicle sits. This is the one scenario that can only truly happen at a forecourt, as anywhere else the car has been driven to get there.
A moment's running, or merely your ignition on. Once primed, the fuel system has pulled petrol from that tank as far as the fuel filter and the fuel lines. Drain, flush, deal with the filter: still normally easy.
Your pump has worked a couple of miles on weakened fuel — that's what driving the car meant. How hard the car was driven counts as much as how far, and the work covers that tank, the fuel lines, the filter and clean fuel through the whole circuit. On the school run to Deal Parochial Church of England Primary School, the miles is small. Very different a second time: a run to Canterbury, under 15 miles away, or some miles on the M20, under 15 miles from Middle Deal, where your engine never stopped running hard.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The engine is telling you your fuel is no longer behaving like diesel. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Mill Road. The drain and flush-through still go first, and they deal with it: if a vehicle is stopped early, permanent damage is very uncommon.
What Middle Deal motorists get told about petrol in a diesel — and the stories in it
Myth: topping up to full with diesel makes it fine. It doesn't. A bigger tank of the same mixture is all it gives, because topping up takes out nothing. The idea behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: a modern diesel copes with a bit of petrol. If anything, the reverse. A modern diesel runs its fuel through finer parts at higher pressure, which makes the protection matter more, not less.
"It starts, it drives, and so there is no harm" — the myth that catches more drivers than any other. A petrol motor fed diesel usually won't run, so the motorist stops and the harm stops with them. Feed petrol to a diesel and it generally starts, ticks over and drives away as if nothing happened — all while its pump wears. Fine and running aren't the same thing.
Myth: a two-stroke additive lets you to drive home. It was an old fix, supposed for another issue. It doesn't put back what petrol has thinned, and the petrol is still inside the tank later.
Myth: "Drain that tank yourself and you are sorted." After the motor has been run, some of the petrol is no longer in that tank: it is in the fuel filter and the fuel lines, and it goes right back through your pump on your next start. On top of that, petrol drained into a can by the road is truly risky.
Petrol in a diesel: how does it happen?
On purpose? Never. Through carelessness? Rarely, if ever. One way only, since of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one mostly won't fit a petrol vehicle. That is how the forecourt makes it simple.
When habit and the vehicle stop matching, it occurs. Courtesy car, hire car, or a car that is new. Two motors on one drive, one petrol, one diesel. Your ordinary forecourt, its pumps suddenly in a different order. Rushing for a train outside Deal and fuelling up en route. Years of petrol motors behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that is when. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
Next time you fill up around Middle Deal: preventing petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most usually do. Read the pump's label; the colour is just a clue.
- The first fill in an unfamiliar vehicle is the time to check the filler flap — inside it, or on the cap, many vehicles state which fuel to use.
- Good intentions count for less than a sticker or a fob in a vivid colour on your diesel's key if a house has one of each. So label it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump. It seems daft and it works.
- Put the phone away. This is an easy mistake to make while you're thinking about something else.
- Add-on devices are available for cars without one, and some diesels come with a filler that won't take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- The moment you realise, stop: less petrol in that tank means a thinner mix. What to do next does not change, though — still do not crank it.
Already put petrol in a diesel in Middle Deal?
The order of things is short, then. Leave it unstarted, with your ignition switched off too. The attendants at the forecourt — whether at the nearest petrol station itself or wherever you filled up — will normally help roll it away from the petrol pump if you ask. Then call 0333 366 0103 and tell us what was put in, roughly how much, and if it has run.
Corrosion and deposits are the trouble with AdBlue, where petrol brings lost protection. So if it was AdBlue, say so — and see its own Middle Deal page.
Why one petrol in a diesel job in Middle Deal costs more than another
The four scenarios above are four separate jobs, so no single quote for this would be honest. What moves your cost is chiefly which of them you are in. The ratio counts next, meaning how much of your tank is petrol, followed by the position of your car and whether reaching it is safe for a technician.
That is why our technicians ask three queries before quoting instead of after: what went in, how much, and if it's run. Given those replies, you get a straight figure rather than a range.
About Middle Deal and its setting
Middle Deal is a suburban area situated on the coast of Kent, with its elevation at around 9 metres above sea level. Middle Deal forms part of the larger Deal urban area, which includes nearby Lower Walmer and Upper Deal. Middle Deal is characterized by its predominantly terraced housing stock, reflecting its history of development as a residential area. Middle Deal is located approximately 14 miles from Canterbury and 69 miles from London.
Across Kent and around Middle Deal: fuel drain cover
Middle Deal sits in the CT postcode area, and our vans that answer petrol in diesel jobs there work the locations around it as well — Deal, Lower Walmer and Upper Deal among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians drain, and the vehicle doesn't need to move to us.
Middle Deal: still at the pump?
In that case, you couldn't be in a better spot. Call, and keep it turned off.