Petrol in a Diesel Car in Dundrum: How Worried Should You Be?
Provided it hasn't been started, worry less than you likely are. Everyone in Dundrum starts with "have I ruined it?", and the honest answer is usually no: petrol resting inside the tank of a diesel remains harmless till priming, cranking or driving draws it into your fuel system. Keep it that way: leave the motor off and ring Petrol in Diesel. Further down, you will find what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to your engine?
Passing through a motor, diesel does two things at once. Lubricating comes before burning; it does both. The high-pressure pump and the injectors are made to very fine clearances, and your diesel passing through them is what keeps those surfaces from grinding against one another.
Of these two tasks, petrol handles the first poorly and the second never. It is runnier than diesel and takes away the protection the fuel system rests 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 opposite of what a diesel needs from its fuel. That's where the clattering comes from.
Put these together and the shape of the problem is clear. Contact does not do the damage — movement does. A tank with petrol in it is a fuel fault. A pump that has been running on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with your fuel to your injectors downstream.
Dundrum, petrol in a diesel: four situations, from mild to major
The best case there can be: filled up, not once started. Being on a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With the petrol held inside that tank alone, it is emptied and rinsed on the spot, and nothing more is needed.
A brief spell of running, or merely the ignition on. With your system primed, the fuel lines and filter already contain petrol that came from the tank. Normally nothing more than clearing, flushing and sorting the filter, so still simple.
Those few miles driven were your pump running on fuel diluted by petrol throughout. The work is your tank, the fuel lines, the filter and clean fuel through the whole circuit, and how hard the car was driven counts as much as how far. Short trips, such as the school run to the local primary school, are one thing. Very different again: a run to Lisburn, under 25 miles away, or some distance on the M77, over 50 miles from Dundrum, where the engine never stopped labouring hard.
Driven till it protested. Knocking, an uneven idle, smoke, a throttle that has gone soft. The fuel isn't behaving like diesel any more, and the motor is saying so. Whether it is the verge on B7041, a lay-by or a side road, stop there and leave it. What comes first is still the drain and flush-through, and that deals with it, with lasting damage very unusual if a car is pulled over soon.
Dundrum people and the petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a fuller tank, still the same mix. Percentage isn't how a diesel fuel system tolerates petrol, whatever that advice presumes.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. At higher pressure, through smaller components: that is how a newer diesel moves its fuel, and so the lubrication matters more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there's no harm done." Diesel in a petrol motor generally means a motor that won't run: the driver stops, and so does the damage. Feed petrol to a diesel and it usually fires up, ticks over and drives away as if nothing happened — all while its pump is wearing. Fine and running are not the same at all.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different issue. None of what petrol weakened gets put back by it — and afterwards, your tank still holds that petrol.
Once the motor has been run, part of that petrol is in the filter and the fuel lines, not that tank — and the next start pulls it right back through your pump. So the myth "drain the tank yourself and you are sorted" does not stand up. Also, a can of petrol filled at the kerbside is truly hazardous.
Petrol in a diesel: how does it happen?
Carelessness is seldom the cause, and nobody means to do it. A diesel nozzle generally won't fit a petrol vehicle, yet the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and only in that direction.
It occurs when habit and your car stop matching. A new car, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. Your usual forecourt, its pumps now in a different order. Filling up in a rush on the way to the nearest station, with a train to catch. Precisely the moment it occurs: after years of driving petrol, a driver fills a diesel Volkswagen Passat for the first time. The hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel at your next fill-up in Dundrum
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Check the pump's label; the colour is just a hint.
- In a car you don't know, look inside the flap over your filler or at the cap before your first fill: many cars state the fuel type there.
- One of each in the home? Mark the key to the diesel — a bright fob, a sticker — since meaning to remember isn't enough.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new motor, say "diesel" aloud. Silly, yes, but it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away then keep your mind on the pump.
- Add-on devices exist for cars without one, and some diesels are built with a filler that won't take a petrol nozzle. Useful — but a backstop only, never a reason to stop checking the label.
- Stop as soon as you notice. Less petrol inside that tank means a thinner mix. It does not change what to do next, which is still not to crank it.
Put petrol in a diesel in Dundrum already?
Then the order of things is short. Leave it unstarted, with the ignition off as well. The attendants at the forecourt — whether at the nearest petrol station itself or wherever you filled up — will normally help push it clear of the petrol pump if you ask. Then phone 0333 366 0103 and tell us what went in, about how much, and if it's run.
Say so if it was AdBlue rather than petrol: it is a separate issue, with its own page for Dundrum, because AdBlue brings corrosion and deposits instead of lost protection.
Why one petrol in a diesel job around Dundrum costs more than another
There's no honest single quote for this, since the four scenarios above are four separate jobs. What moves the cost is chiefly which of them you are in. Two things follow that: the petrol that was put in as a proportion of what your tank takes, then the spot the car is in and whether our van can get to it safely.
What got in, how much, and if it has run — three queries our technicians ask before pricing, not after, for exactly that reason. The replies turn a range into a straight figure.
About Dundrum itself
Dundrum is a small coastal locality in County Down, Northern Ireland, with a population of around 816 people. Dundrum sits at a low elevation of 8 metres, near the towns of Ballymartin, Ballykinler, and Clough. Dundrum is characterized by its terraced housing and is located approximately 19 miles from Lisburn. Dundrum is also situated near the coast, providing scenic views and a unique setting.
Across County Down and in Dundrum: fuel drain cover
Ballymartin, Ballykinler and Clough are among the places near Dundrum that the same vans work, answering petrol in diesel jobs across Dundrum's BT postcode area. No need to move your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots we drain.
In Dundrum and still at the petrol pump?
Nothing beats it: that is where you now are. Ring, and leave it switched off.