Should You Worry? Petrol in a Diesel Car in Brynbryddan
Not started? Then less worried than you probably are. Everyone around Brynbryddan starts with "have I ruined it?", and the fair answer is normally no: petrol left in that tank of a diesel remains harmless till priming, cranking or driving draws it into your fuel system. Leave the engine off then call Petrol in Diesel — that is how you keep it like that. The remainder of this page sets out 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 again.
What petrol in a diesel does to the engine
Passing through a motor, diesel does two jobs at the same time. Before it burns, it lubricates — then it burns. Very fine gaps are built into the injectors and the high-pressure fuel pump, and only the diesel flowing through keeps those surfaces from grinding together.
Poorly at the first, not at all at the second: that's petrol. The clattering comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips out the protection the system depends on, and any pump working on such a blend is wearing itself.
Combined, those leave the shape of the problem plain. Contact doesn't do the damage — movement does. Where that petrol is only inside the tank, it is a fault of fuel, nothing more. The beginning of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to the injectors downstream.
How serious is petrol in a diesel? Four situations we see in Brynbryddan
Fuelled up, not once started. The best case there is. Being on a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol held inside that tank alone, it's drained and flushed on the spot, and nothing more is needed.
A brief spell of running, or just your ignition on. Your system has been bled, so petrol has left that tank and reached your filter and the lines. That is generally still a straightforward task — a drain, a flush, and the fuel filter dealt with.
Those few miles driven meant your pump working on fuel thinned by petrol the whole way. The work is that tank, the lines, the filter and fresh fuel through the entire system, and how hard your car was driven matters as much as how far. Short trips, such as the school run to the local primary school, are one matter. Any miles on the M4, under 3 miles from Brynbryddan, means the engine working hard throughout, and a run to Swansea, under 10 miles away, makes a very different job too.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The motor is telling you your fuel is no longer behaving like diesel. Stop on the spot — on the verge on Heol-y-Foel, at the kerb, down a side road — and don't move it again. What goes first is still the drain and flush, and that sorts it out, with lasting damage very unusual if a vehicle is pulled over quickly.
What Brynbryddan drivers get told about petrol in a diesel — and the myths in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Topping up takes out nothing; it gives you a fuller tank of the same mixture. That guidance presumes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. Smaller components and higher pressure are the way a modern diesel runs its fuel, and that makes the lubrication matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there is no harm done." A petrol motor fed diesel usually will not run, and so the motorist stops and the harm stops with them. A diesel fed petrol usually starts, ticks over and drives away as if nothing has happened, whilst the pump grinds. Running is not the same as fine.
"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 the petrol is still in your tank afterwards.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol lies in the filter and lines, ready to go right back through your pump on your next start. Besides, petrol drained into a can by the road is genuinely risky.
Why petrol in a diesel occurs so easily
A careless moment is rarely the cause, and no one means to do it. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol motor at all. The forecourt makes it simple, and the mistake runs one way.
When routine and the vehicle stop matching, it takes place. Courtesy car, hire car, or a motor that is brand new. One petrol and one diesel on the driveway of the same household. A well-known forecourt with the pumps in a different order. Filling up in a hurry on the way to Baglan, with a train to catch. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. With rain, a call coming in, or a car full of children to deal with, the hand simply does what it has always done.
How to prevent petrol in a diesel at your next fill-up in Brynbryddan
- A green handle for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Trust the label on the petrol pump, not the colour.
- In a car you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of cars state the fuel type there.
- Mark your key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- Before the nozzle comes off the pump the first time you fill a hired or new motor, say "diesel" aloud. Silly, perhaps, yet it does the trick.
- Whilst you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to reject a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop checking the petrol pump.
- The moment you notice, stop: less petrol in the tank makes a thinner blend. What to do next does not change, though — still do not start the car.
Brynbryddan: already put petrol in a diesel?
Then the order of things is short. Starting it is out, and so is switching on the ignition. Yet at the forecourt, at Tesco or anywhere else? Ask the attendants to help you push it clear of the petrol pump. What was put in, roughly how much, and if it's run: tell us those when you phone 0333 366 0103.
Corrosion and deposits form the issue with AdBlue, where petrol brings lost protection. So if it was AdBlue, say so — and read its own Brynbryddan page.
One petrol in a diesel task in Brynbryddan costs more than another. Why?
Four separate tasks lie behind the four scenarios above — which is why there is no fair single price. Chiefly, the cost moves with which one you are in. Where the vehicle is matters too, and whether a van can safely get to it, after the share of petrol to what that tank takes.
What was put in, how much, and if it has run — three queries we ask before pricing, not after, for precisely that reason. Those answers are what change a range into one firm number.
About Brynbryddan, briefly
Brynbryddan is a coastal locality in Neath Port Talbot, situated near the city of Swansea and overlooking the Bristol Channel. Brynbryddan sits at an elevation of 96 metres, with semi-detached housing being the predominant type of accommodation in the area. Brynbryddan is close to nearby places such as Cwmavon, Pantdu, and Caerhendy, and is approximately 156.6 miles west of London.
Fuel drain cover in Brynbryddan and across Neath Port Talbot
Petrol in diesel call-outs in Brynbryddan — part of the SA postcode area — go to teams that likewise cover the locations around it, Cwmavon, Pantdu and Caerhendy among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations we drain, and the vehicle does not need to move to us.
At the petrol pump in Brynbryddan, still?
Then you are in the best spot there is. Keep the vehicle turned off, then ring.