Should You Worry? Petrol in a Diesel Car in Stoneyford
Far less than you likely are, provided it hasn't been started. "Have I wrecked it?" is the first question everyone in Stoneyford asks, and the truthful answer is usually no, since petrol left in a diesel tank hurts nothing until it is dragged through the fuel system — by ignition priming, by your starter, or by driving. Keep it like that: leave your motor off then call Petrol in Diesel. Further down, this page sets out what petrol actually does inside a diesel, how far it might have gone, and how to stop it happening to you again.
Petrol in a diesel: what does it do to your engine?
On its way through an engine, diesel does two tasks. Before it ignites, it lubricates — and then it burns. Very fine clearances are built into the fuel injectors and the high-pressure fuel pump, and just your diesel running through stops those surfaces grinding together.
Of these two jobs, petrol manages the first badly and the second never. It is thinner than diesel and takes away the protection the system hinges on, and so a pump running on a petrol blend 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's where the knocking comes from.
Taken together, they show what shape the trouble takes. Contact doesn't do the damage — circulation does. Any tank with petrol in it is a fuel fault. A pump that has been labouring on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with the fuel to your injectors further on.
Stoneyford, petrol in a diesel: four cases, from mild to significant
The best case there is: filled up, never started. On a forecourt, and genuinely only there, that petrol is still confined to that tank — because everywhere else the vehicle was driven to get to it. The task is draining and rinsing on the spot.
Ignition on, or started for a second. Once primed, your system has drawn petrol from your tank up to the fuel filter and the fuel lines. Still generally straightforward: drain, flush, and the fuel filter seen to.
A couple of miles driven, and your pump has spent every one of them running on thinned fuel. How hard the vehicle was driven counts as much as how far, and this work takes in the tank, the fuel lines, the fuel filter and clean fuel through the whole circuit. On the school run to the local primary school, the miles is short. Driving as far as Lisburn, under 10 miles away, makes a very different task — as does any distance on the M77, over 50 miles from Stoneyford, with the engine working hard the whole time.
Clattering, a ragged idle, smoke, a throttle gone soft: driven till it complained. That is your engine telling you its fuel no longer is behaving like diesel. Stop on the spot — on the verge on Heugh Road, at the kerb, down a side road — and don't move it. The fuel drain and flush-through still go first, and they take care of it: when a vehicle is pulled over soon, permanent damage is very uncommon.
Petrol in a diesel myths Stoneyford drivers hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing comes out when you top up — your tank just carries more of the same mixture. A diesel fuel system does not tolerate petrol by percentage in the way that guidance supposes.
If anything, the reverse holds. Myth: "A modern diesel can cope with a bit of petrol." A current diesel runs its fuel through finer parts at higher pressure, which makes the protection count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools people. The motorist of a petrol engine fed diesel normally has no choice but to stop, since it will not run, and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump wears. Being able to run isn't the same as being fine.
Myth: a two-stroke additive makes it safe to drive home. It is an old workaround, meant for another fault. What petrol has thinned remains weakened, and that petrol remains inside that tank regardless.
The next start sends petrol back round the pump out of your lines and the filter, where some of that ends up after the engine has been run. That's why draining the tank yourself doesn't leave you sorted — a myth. Emptying petrol into a can at the roadside is also genuinely risky.
Petrol in a diesel: how does it occur?
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle generally will not go into a petrol car, yet the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error simple, and only in that direction.
Routine and the vehicle falling out of step is how it happens. Courtesy car, hire car, or a vehicle that is brand new. Two motors on one driveway, one petrol, one diesel. Your normal forecourt, its pumps now in a different order. A rushed fill on the way to the nearest station with a train to catch. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. Throw in a back seat full of kids, a phone call or rain, and the hand wins.
Stoneyford motorists: how to avoid petrol in a diesel next time
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Check the petrol pump's label; the colour is just a clue.
- Check your filler flap. Many vehicles state the fuel inside the flap or on the cap. Look at it on the first fill in any vehicle you do not know.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, for a house with one of each.
- It sounds daft and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump.
- 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 petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to block a petrol nozzle, and add-on devices exist for motors without one. They are a safety net, not a reason to stop reading the petrol pump.
- Stop the moment you notice. Less petrol in your tank makes a thinner mixture. It does not change what to do next, which is still not to start it.
Stoneyford: already put petrol in a diesel?
The order of things is short, then. Starting it is out, and so is switching on the ignition. Ask the staff to help you roll it away from the pump if you're still on the forecourt, whether that's the nearest petrol station or anywhere else. Call 0333 366 0103 next, with three answers — your fuel, the approximate amount, and whether it has run.
If it was AdBlue rather than petrol, say so. That's a separate fault — corrosion and deposits rather than lost lubrication — and it has its own page for Stoneyford.
What makes one Stoneyford petrol in a diesel job cost more than the next
The four situations above are four different tasks, so no single quote for this would be honest. Which of them you're in is mostly what shifts your cost. Two things follow that: the petrol that got in as a proportion of what that tank takes, then the place the car is in and whether a van can get to it safely.
That's why our technicians ask three questions before pricing instead of after: what got in, how much, and whether it has run. Their replies are what change a range into one firm number.
About Stoneyford
Stoneyford is a small locality in County Antrim, situated inland at an elevation of 132 metres, approximately 5 miles from Lisburn. Stoneyford is characterised by its semi-detached housing and is close to nearby places such as Dundrod, Milltown, and Glenavy. Stoneyford has a population of around 720 people and is located about 326 miles from London.
Stoneyford and County Antrim: where our fuel drain cover runs
Petrol in diesel call-outs in Stoneyford — part of the BT postcode area — go to vans that likewise cover the locations round it, Dundrod, Milltown and Glenavy among them. The vehicle does not need to come to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the petrol pump in Stoneyford?
Then, you could not be in a better position. Call, and keep it turned off.