Should You Worry? Petrol in a Diesel Car in Hendy
Unstarted? Then less anxious than you probably are. Petrol resting in a diesel tank does nothing to your motor until something draws it through your fuel system — your ignition priming the pump, your starter, or the drive itself. So the fair answer to the first question anyone around Hendy asks, "have I ruined it?", is usually no. To leave the vehicle that way, ring Petrol in Diesel then leave the motor switched off. What petrol actually does to a diesel, how to judge how far it has gone, and how to keep it from happening again: that is the rest of this page.
What petrol in a diesel does to your engine
On its way through an engine, diesel has two tasks. It ignites, and before it combusts it lubricates. Very fine gaps are built into the fuel injectors and your high-pressure pump, and only your diesel running through keeps those surfaces from grinding together.
Poorly at the first, not at all at the second: that is petrol. It is runnier than diesel and strips away the protection your fuel system hinges on, so a pump running on a petrol mix is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the rattling comes from.
Seen together, they show the shape the issue takes. Not contact but movement is what does the harm. All a tank with petrol in it amounts to is a fuel fault. The start of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with the fuel to your injectors beyond it.
Four situations our engineers see in Hendy: how serious is petrol in a diesel?
Fuelled but never started — the best it gets. Only your tank has petrol in it, and so the job is emptying your tank and purging the fuel system where the vehicle sits. This scenario can only really take place on a forecourt: anywhere else, the car got there by being driven.
Started for a second, or just the ignition on. The system has been bled, so petrol has left that tank and got to your filter and the fuel lines. That is normally still a simple job — a drain, a flush, and the filter seen to.
Those few miles on the road meant the pump running on fuel thinned by petrol throughout. Mileage is only half of it; how hard it was driven counts just as much. Either way the work runs to the tank, your lines, the fuel filter and fresh fuel through the entire circuit. The school run to the local primary school is one matter. Very different again: a run to Swansea, under 10 miles away, or any mileage on the M4, under a mile from Hendy, where the motor kept labouring hard.
Driven on till it complained — rattling, smoke, a ragged idle, a dead throttle. The fuel is not behaving like diesel any more, and your motor is saying so. Leave it wherever it stops: a lay-by, a side street, the verge on Sawel Terrace. Permanent damage is very rare when a vehicle is stopped early, and the drain and flush that still go first deal with it.
Stories Hendy people hear about petrol in a diesel
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. That advice presumes a diesel fuel system handles petrol by percentage. It does not.
Myth: a current diesel copes with a bit of petrol. If anything, the opposite. Protection matters more on newer diesels, not less, since their fuel passes through smaller parts at higher pressure.
"It starts, it drives, so no harm done" — the myth that catches more people than any other. A petrol motor fed diesel normally will not run, and so the motorist stops and the damage 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 your pump grinds. A running engine doesn't mean fine.
An old workaround for a distinct issue lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol diluted gets put back by it — and afterwards, your tank still holds the petrol.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol sits in the filter and lines, waiting to go right back through your pump on the next start. And, a can of petrol filled at the kerbside is genuinely hazardous.
Petrol in a diesel: how does it occur?
No one does it on purpose, and it is seldom carelessness. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally will not fit a petrol vehicle. That's how the forecourt makes it straightforward.
It occurs when habit and the car stop matching. Hire cars, courtesy cars, and vehicles that are new to you. Two motors on one driveway, one petrol, one diesel. A forecourt you know, only with its pumps arranged differently. A hurried fill en route to Pontarddulais with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a motorist used to petrol: exactly when it occurs. Throw in rain, a phone call or a back seat full of children, and your hand does what it has always done.
Avoiding petrol in a diesel next time you fill up around Hendy
- The label is what counts, and so check the petrol pump rather than the colour: in the UK unleaded handles are normally green and diesel black, yet not on each forecourt.
- The first fill in an unfamiliar car is the time to check the filler flap — inside it, or on the cap, plenty of motors state which fuel to use.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key if a house has one of each. So mark it.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It seems daft and it does the trick.
- Mistakes like this are easy to make while your mind is on something else, and so the phone goes away.
- Add-on devices are available for cars without one, and some diesels are built with a filler that won't accept a petrol nozzle. Useful — but a backstop only, never a reason to stop checking the label.
- Spotting it mid-fill? Stop at once. A weaker blend follows from less petrol inside that tank, yet the next step remains the same: don't fire it up.
Put petrol in a diesel around Hendy already?
Then the order of things is short. Never fire it up, and do not switch the ignition on. If you are still at the forecourt — Shell or anywhere else — ask the staff to help you push the vehicle away from the petrol pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it has been run.
Say so if it was AdBlue instead of petrol: it is a different problem, with its own page for Hendy, because AdBlue brings corrosion and deposits rather than lost lubrication.
Why one petrol in a diesel task around Hendy costs more than another
A fair single price does not exist here: four situations, four separate tasks. Chiefly, your cost moves with which one you're in. The share counts next, meaning how much of that tank is petrol, and then the position of the car and whether getting to it is safe for our van.
Three queries come first, before any quote, instead of after — what was put in, how much, has it run — and that is the reason. Their answers are what turn a range into one firm number.
About Hendy and its setting
Hendy is a small coastal village in Carmarthenshire, situated near the mouth of the River Loughor, with Fforest and Pontarddulais nearby. Hendy has a population of around 1197 people and is characterized by semi-detached housing. Hendy is located close to Swansea, approximately 8 miles away, and is set in a low-lying coastal area at an elevation of 14 metres. Hendy benefits from its proximity to the city while maintaining a distinct village identity.
Hendy and Carmarthenshire: where our fuel drain cover runs
Fforest, Pontarddulais and Talyclun are among the locations around Hendy that the same vans work, answering petrol in diesel call-outs across Hendy's SA postcode area. Our engineers drain wherever the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Still at the petrol pump around Hendy?
Nothing beats it: that is where you now are. Leave the vehicle turned off, and ring.