Petrol in a Diesel Car in Loughinisland: How Worried Should You Be?
Provided it has not been started, worry far less than you probably are. Until the ignition primes the pump, your starter cranks, or the car is driven, petrol in a diesel tank simply rests there and does nothing. Which means the honest reply to the first Loughinisland question — "have I wrecked it?" — normally no. To leave the car that way, ring Petrol in Diesel and leave your motor alone. Further down, this page sets out what petrol actually does inside a diesel, how far it may have gone, and how to stop it happening to you a second time.
The engine and petrol in a diesel: what happens
Diesel has two tasks on its way through a motor. Oiling comes before burning; it does both. What stops the surfaces inside the high-pressure fuel pump and the injectors from wearing against each other is the diesel flowing through them — they are built to extremely fine gaps.
Petrol handles the first job badly and the second not at all. A pump working on a petrol blend is wearing itself out, because petrol is runnier than diesel and strips out the protection the fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that is where the knocking starts.
Taken together, they show what shape the issue has. Not contact but movement is what does the harm. Where that petrol is only inside your tank, it is an issue of fuel, nothing more. Whatever a worn pump sheds goes on, borne by the fuel, into the injectors further along, which is why a pump that has worked on the petrol is where a mechanical issue begins.
Four situations our engineers see in Loughinisland: how bad is petrol in a diesel?
Fuelled up, never started. The best case there is. Being at a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With that petrol kept inside your tank alone, it's drained and purged on the spot, and nothing more is needed.
Your ignition switched on, or a brief start. Once primed, the system has pulled petrol from the tank up to the filter and the fuel lines. Still usually simple: drain, flush, and the fuel filter seen to.
Your pump has spent a couple of miles on weakened fuel — that's what driving the car meant. How hard the vehicle was driven matters as much as how far, and the work takes in the tank, the lines, the filter and clean fuel through the entire system. Short trips, like the school run to the local primary school, are one thing. Very different again: a trip to Lisburn, under 15 miles away, or any distance on the M77, over 50 miles from Loughinisland, where the motor kept working hard.
Driven on until it complained — knocking, smoke, a ragged idle, a soft throttle. The fuel isn't acting like diesel any more, and your motor is saying so. Stop wherever you are — the verge on B7041, a lay-by, a side street — and leave the car where it is. Long-term damage is very uncommon when a car is stopped soon, and the drain and flush-through that still come first take care of it.
Petrol in a diesel stories Loughinisland drivers hear
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you are left with a fuller tank, still the same mixture. Percentage is not how a diesel fuel system copes with petrol, whatever that advice presumes.
Myth: a modern diesel copes with a bit of petrol. If anything, the reverse. At higher pressure, through smaller components: that is how a modern diesel handles its fuel, so the lubrication matters more, not less.
One myth that catches motorists off guard: if it starts and drives, it must be unharmed. Diesel in a petrol motor usually leaves a motor that will not run: the driver stops, and so does the harm. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, while your pump wears. Fine and running are not the same at all.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different problem. It does not put back what petrol has thinned, and that petrol is still in your tank afterwards.
"Drain it yourself and you are sorted" — a myth, since after it has been running some petrol lies in the filter and lines, ready to go right back through the pump at your next start. It's also genuinely hazardous to drain petrol into a can at the roadside.
How petrol ends up: petrol in a diesel
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol car at all. The forecourt makes it simple, and the error runs one way.
Habit and the car getting out of step is when it happens. Courtesy car, hire car, or a vehicle that is brand new. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps laid out differently. Racing for a train at the nearest station and filling up en route. Years of petrol cars behind you, a diesel Volkswagen Tiguan in front of you at the forecourt for its first tank — that's when. Add rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Avoiding petrol in a diesel next time you fill up in Loughinisland
- Green for unleaded and black for diesel is usual in the UK — but not on each forecourt. Trust the label on the petrol pump, not the colour.
- Many vehicles state the fuel inside the filler flap or on the cap, and so check it on the first fill in a motor you do not know.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a household with one of each.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. It sounds daft and it works.
- Mistakes like this are straightforward to make whilst your mind is on something else, so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to block a petrol nozzle, and add-on devices exist for vehicles without one. They are a safety net, not a reason to stop checking the pump.
- Stop the moment you notice. Less petrol in the tank makes a thinner mix. It does not change what to do next, which is still not to start the vehicle.
Loughinisland: already put petrol in a diesel?
The order of things is short, then. Don't switch the ignition on, and don't fire it up. Yet at the forecourt, at the nearest petrol station or anywhere else? Ask the attendants to help you roll it clear of the pump. Call 0333 366 0103 next, with three answers — the fuel, the rough amount, and whether it has run.
Corrosion and deposits form the trouble with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and see its own Loughinisland page.
Why one petrol in a diesel job in Loughinisland costs more than another
Four different tasks sit behind the four situations above — which is why there is no fair single quote. Which of them you're in is chiefly what shifts your cost. Where the car is matters too, and whether a van can safely get to it, after the share of petrol to what your tank holds.
That's why we ask three queries before pricing rather than after: what went in, how much, and whether it's run. Given those replies, you get a straight figure instead of a range.
About Loughinisland and where it is
Loughinisland is a small locality in County Down, situated inland at an elevation of 45 metres, and is located near the communities of Drumaness, Seaforde, and Clough. Loughinisland has a population of approximately 848 people, and its housing stock is predominantly composed of detached homes. Loughinisland is within commuting distance of Lisburn, which is about 14.6 miles away.
Loughinisland and County Down: where our fuel drain cover reaches
Loughinisland waits in the BT postcode area, and our teams that answer petrol in diesel calls there work the spots near it as well — Drumaness, Seaforde and Clough among them. The car doesn't need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the pump around Loughinisland, still?
In that case, you couldn't be in a better position. Keep it off. Call.