Should You Worry? Petrol in a Diesel Car in Springfield
Probably less than you are now — provided nobody has started the car. Until the ignition primes your pump, your starter cranks, or the vehicle is driven, petrol in a diesel tank just rests there and does nothing. Which makes the honest reply to that first Springfield query — "have I ruined it?" — normally no. To keep it that way, phone Petrol in Diesel and leave the engine switched off. The remainder of this page covers what petrol really does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
What petrol in a diesel does to the motor
On its way through an engine, diesel has two jobs. Before it combusts, it lubricates — then it ignites. Very fine gaps are built into your injectors and your high-pressure pump, and just your diesel running through keeps their surfaces from grinding together.
Petrol handles the first task poorly and the second not at all. Being less viscous than diesel, petrol strips away the protection a fuel system needs, so a pump on the blend to wear itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is why you get the knocking.
The shape of the issue is clear once you put those together. Not contact but movement is what causes the damage. A tank with petrol in it is a fuel problem. The start of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with your fuel to the fuel injectors beyond it.
Four scenarios our engineers see in Springfield: how serious is petrol in a diesel?
Fuelled, and not started: nothing beats it. Being at a forecourt is what makes this the case: elsewhere, the vehicle has been driven there to begin with. With that petrol held in the tank alone, it is cleared and cleaned on the spot, and nothing more is needed.
The ignition turned on, or a short start. With your system primed, your lines and filter now contain petrol that has come from your tank. Usually nothing more than emptying, rinsing and sorting the fuel filter, so still straightforward.
Your pump has spent a few miles on weakened fuel — that is what driving the vehicle meant. How hard the vehicle was driven matters as much as how far, and this work covers the tank, the fuel lines, the fuel filter and clean fuel through the whole circuit. Short trips, like the school run to the local primary school, are one matter. Very different a second time: a trip to Armagh, under 50 miles away, or some distance on the M77, over 50 miles from Springfield, where your engine kept running hard.
Driven until it complained. Clattering, a lumpy idle, smoke, a throttle that has gone soft. That is your motor telling you its fuel no longer is behaving like diesel. Whether it's the verge on Rock Street, a lay-by or a side road, stop where you are then leave it. What comes first is still the drain and flush-through, and that takes care of it, with long-term damage very rare when a car is stopped soon.
Springfield drivers 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. Topping up removes nothing; it gives you a bigger tank of the same mixture. A diesel fuel system doesn't accept petrol by percentage in the way that advice presumes.
Not so: a newer diesel copes with a bit of petrol. Rather, the opposite. Lubrication matters more on newer diesels, not less, because their fuel passes through smaller components at higher pressure.
Myth: "If it starts and drives, there's no damage done." This is the one that fools motorists. Feed diesel to a petrol motor and it generally won't run, so the motorist stops — and the harm stops with them. Feed petrol to a diesel and it normally starts, ticks over and drives away like nothing happened — all the while its pump is wearing. Running doesn't mean fine.
Myth: a two-stroke additive makes it safe to drive home. It is an old fix, meant for another problem. None of what petrol diluted is put back by it — and later, that tank still holds that petrol.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol sits in the fuel filter and lines, ready to go right back through your pump at the next start. On top of that, petrol emptied into a can by the road is genuinely dangerous.
Why petrol in a diesel happens at all
No one does it on purpose, and it is rarely carelessness. One way only, because 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 car. That's how the forecourt makes it straightforward.
When habit and the car stop matching, it happens. A new motor, a hire car or a courtesy car. Two motors on one drive, one petrol, one diesel. A well-known forecourt with the pumps in a different order. A rushed fill en route to the nearest station with a train to catch. Years of petrol vehicles behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that's when. Throw in rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
Avoiding petrol in a diesel next time you fill up around Springfield
- The label is what counts, so read the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, yet not on each forecourt.
- The first fill in an unfamiliar vehicle is the time to check your filler flap — on it, or on the cap, many vehicles state which fuel they take.
- Label your key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- It sounds silly and it works: on the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump.
- Whilst you're 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 come with a filler designed to reject a petrol nozzle, and add-on devices are available for cars without one. They are a backstop, not a reason to stop checking the pump.
- Less petrol means a weaker mix, so stop the moment you realise — though remembering that your next step is unchanged. It is still not to fire it up.
Petrol already in a diesel in Springfield? Start here
Then the order of things is short. Never fire it up, and do not turn your ignition on. Ask the staff to help you push it clear of the pump if you are still at the forecourt, whether that's the nearest petrol station or somewhere else. Phone 0333 366 0103 next, with three facts — your fuel, the approximate volume, and whether it's run.
Corrosion and deposits form the problem with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and read its own Springfield page.
One petrol in a diesel task in Springfield costs more than another. Why?
Four separate jobs sit behind the four scenarios above — which is why there's no fair single quote. Which of them you're in is mostly what moves your cost. The ratio matters next, meaning how much of the tank is petrol, followed by the position of the vehicle and whether reaching it is safe for our van.
Three queries come first, before quoting, rather than after — what was put in, how much, has it run — and this is the reason. Their answers are what turn a range into one firm number.
About Springfield, for a moment
Springfield is a small locality in County Fermanagh, situated inland at an elevation of 48 metres. Springfield lies near several nearby settlements, including Ballycassidy, Trory, and Monea, and is approximately 42 miles from the city of Armagh. Springfield has a population of around 527 people, predominantly living in detached housing. Springfield is located a significant distance from major cities, with London being around 373 miles away.
Fuel drain cover around Springfield and across County Fermanagh
Ballycassidy, Trory and Monea are among the places near Springfield that the same teams work, answering petrol in diesel jobs across Springfield's BT postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations our engineers work, and the vehicle doesn't need to come to us.
In Springfield and still at the pump?
Then, you couldn't be in a better position. Keep it switched off, and ring.