Should You Worry? Petrol in a Diesel Car in Leitrim
Not started? Then less anxious than you likely are. Until your ignition primes the pump, your starter turns, or your vehicle is driven, petrol in a diesel tank simply rests there and does nothing. Which makes the truthful reply to the first Leitrim query — "have I wrecked it?" — normally no. Leave the engine off and phone Petrol in Diesel — that is how you keep it that way. The rest of this page explains what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you a second time.
Your engine and petrol in a diesel: what happens
On its way through an engine, diesel has two tasks. It combusts, and before it burns it protects. Designed to extremely fine tolerances, the injectors and the pump depend on your diesel flowing through them to keep their surfaces from wearing against one another.
Poorly at the first, not at all at the second: that is petrol. A pump working on a petrol mixture is wearing itself out, because petrol is runnier than diesel and takes away the protection the fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where the clattering starts.
Taken together, they make clear what shape the issue takes. The harm is done by movement, not by contact. All a tank with petrol in it amounts to is a fuel issue. Once your pump has been labouring on that petrol, a mechanical problem has started: anything shed by a pump that is wearing down is carried onward to the fuel injectors with the fuel.
How serious is petrol in a diesel? Four scenarios we see in Leitrim
The best case there can be: filled up, never started. Just your tank has petrol in it, so the task is emptying your tank and purging your system where the vehicle sits. This situation can only really take place on a forecourt: anywhere else, the vehicle got there by being driven.
Your ignition turned on, or a short start. Once primed, your system has pulled petrol out of your tank up to the filter and your lines. Still usually simple: drain, flush, and the filter sorted.
Driven a couple of miles. Now your pump has spent these miles working on diluted fuel. How hard your car was driven counts as much as how far, and this work covers that tank, the lines, the filter and clean fuel through the whole circuit. A school run to the local primary school is one thing. A run as far as Lisburn, under 25 miles away, is a very different job. So is any miles on the M77, over 50 miles from Leitrim, where the motor has been labouring hard the whole time.
Driven on till it complained — clattering, smoke, a ragged idle, a dead throttle. What you are hearing is your engine reporting fuel that no longer runs like diesel. Stop where you are — on the verge on High Row, at the kerb, down a side road — and don't move it again. A car stopped soon very seldom has permanent damage, as the drain and the flush, which still come first, take care of it.
Leitrim people and the petrol in a diesel stories they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing comes out when you top up — your tank simply holds more of the same blend. Percentage isn't how a diesel fuel system copes with petrol, however much that guidance assumes.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." A newer diesel sends its fuel through smaller components at higher pressure, which makes the protection count more, not less.
"It starts, it drives, and so there is no harm" — the myth that catches most drivers than any other. Any petrol motor fed diesel usually won't run, so the driver stops and the damage stops with them. While your pump grinds, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. Running doesn't mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an outdated workaround for a different fault. None of what petrol thinned is put back by it — and later, your tank still contains that petrol.
The next start sends petrol back round the pump out of the lines and the filter, where some of it sits once your engine has run. That is why a DIY tank drain does not leave you sorted — a myth. Clearing petrol into a can at the roadside is also genuinely risky.
Petrol in a diesel: how does it occur?
No one does it on purpose, and it is seldom carelessness. A diesel nozzle generally won't go into a petrol vehicle, but the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in that direction.
The moment routine stops matching the vehicle is the moment it occurs. A new motor, a hire car or a courtesy car. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. Racing for a train outside the nearest station and filling up en route. A new-to-you diesel Renault Clio, its first fuelling, and a motorist used to petrol: precisely when it occurs. Throw in a back seat full of children, a phone call or rain, and habit wins.
Next time you fill up around Leitrim: preventing petrol in a diesel
- The label is what counts, so read the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- The first fill in a new vehicle is the time to check the filler flap — inside it, or on the cap, plenty of motors state the fuel they take.
- A coloured fob or a sticker on your diesel's key does more than any amount of intending to remember, in a household with one of each.
- Before the nozzle comes off the pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Silly, perhaps, but it works.
- 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 pump.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add are available for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Less petrol makes a thinner mixture, and so stop as soon as you realise — though remembering that your next stage is unchanged. It's still not to start the vehicle.
Put petrol in a diesel in Leitrim already?
The order of things is short, then. Do not crank it, and do not switch your ignition on. If you're still on the forecourt — the nearest petrol station or anywhere else — ask the attendants to help you roll the car away from the pump. Phone 0333 366 0103 next, with three answers — your fuel, the approximate quantity, and if it's run.
Say so if it was AdBlue instead of petrol: it is a different problem, with its own page for Leitrim, since AdBlue brings corrosion and deposits instead of lost protection.
One petrol in a diesel job in Leitrim costs more than another. Why?
The four scenarios above are four separate tasks, so no single quote for this would be fair. The situation itself does most of the work of moving your cost. The ratio counts next, meaning how much of your tank is petrol, followed by the location of your car and whether getting to it is safe for a technician.
That is why our engineers ask three questions before pricing rather than after: what got in, how much, and whether it's run. A range turns into a straight figure once the replies are in.
About Leitrim
Leitrim is a small locality in County Down, situated inland at an elevation of 116 metres, and is located approximately 15.7 miles from Lisburn. Leitrim is characterized by its predominantly detached housing stock, reflecting the area's residential nature. Leitrim sits near other local places such as Castlewellan, Annsborough, and Moneyslane, in the wider countryside of Northern Ireland.
Fuel drain cover around Leitrim and across County Down
Castlewellan, Annsborough and Moneyslane are among the locations around Leitrim that the same teams work, answering petrol in diesel jobs across Leitrim's BT postcode area. Our engineers drain wherever your vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the petrol pump around Leitrim?
Then you are in the best spot there can be. Leave it turned off, then ring.