Should You Worry? Petrol in a Diesel Car in Myddyn-fych
Not started? Then less worried than you probably are. Everyone in Myddyn-fych begins with "have I wrecked it?", and the honest answer is normally no: petrol left inside your tank of a diesel stays harmless until priming, cranking or driving draws it into the fuel system. Leave your engine off then ring Petrol in Diesel — that is how you keep it like that. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has got, and the way to make sure you never do it again.
Inside the motor: what petrol in a diesel really does
Diesel does two tasks on its way through a motor. It lubricates first, and only then does it burn. Built to very fine clearances, the fuel injectors and your pump rely on your diesel flowing through them to keep their surfaces from wearing against one another.
Of these two jobs, petrol handles the first badly and the second not at all. A pump running on a petrol mix 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 reverse of what a diesel wants from its fuel — and that's where the clattering comes.
Together, those leave the shape of the problem clear. It's movement that causes the damage, not contact. A tank with petrol in it is a fuel fault. The beginning of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with the fuel to your injectors downstream.
Petrol in a diesel around Myddyn-fych: how bad is it? Four cases
Fuelled but not once started — as good as it gets. Being at a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With that petrol held in the tank alone, it's drained and purged on the spot, and nothing more is needed.
A brief spell of running, or just the ignition on. Your system has been primed, so petrol has left your tank and got to the fuel filter and the lines. Drain, flush, deal with the fuel filter: still usually straightforward.
A couple of miles driven, and your pump has spent every one of them labouring on diluted fuel. Tank, lines, filter, then fresh fuel put through the entire system: that's the work, and the way your car was driven counts as much as the miles. On the school run to the local primary school, the distance is small. A run as far as Swansea, under 15 miles away, is a very different task. So is any miles on the M4, under 5 miles from Myddyn-fych, where the motor has been running hard throughout.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven until it complained. The fuel isn't behaving like diesel any more, and the engine is telling you. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Bonllwyn. A vehicle stopped soon very seldom has permanent damage, since the fuel drain and the flush-through, which still go first, sort it out.
Myths Myddyn-fych drivers hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A fuller tank of the same mixture is all it gives, because topping up removes nothing. That advice assumes a diesel fuel system handles petrol by percentage. It doesn't.
"Modern diesels can handle a little petrol" — a myth, and closer to the opposite. At higher pressure, through more precise components: that's how a newer diesel handles its fuel, and so the lubrication matters for more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that catches motorists. Diesel in a petrol motor usually means a motor that won't run: the motorist stops, and so does the harm. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile 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 distinct problem. It doesn't put back what petrol has weakened, and the petrol is still in your tank after that.
The next start draws petrol back round your pump out of the lines and your filter, where some of that sits once the engine has been run. That's why draining the tank yourself does not sort it — a myth. Clearing petrol into a can at the roadside is also genuinely risky.
How does petrol in a diesel occur?
No one does it on purpose, and it's rarely carelessness. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol motor at all. The forecourt makes it simple, and the slip runs one way.
When routine and the vehicle stop matching, it occurs. Courtesy car, hire car, or a vehicle that is new. Two cars on one driveway, one petrol, one diesel. Your ordinary forecourt, its pumps now in a different order. A train to catch, and a hurried fill on the way to Ammanford. The first fill-up in a diesel Renault Clio after years of driving petrol is precisely the moment it occurs. With rain, a call arriving, or children to deal with, the hand simply does what it always has.
Preventing petrol in a diesel next time you fill up around Myddyn-fych
- The label is what counts, and so read the petrol pump instead of the colour: in the UK unleaded handles are normally green and diesel black, yet not on each forecourt.
- Inspect the filler flap. Many vehicles state the fuel type inside the flap or on the cap. Look at it on your first fill in a car you don't know.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, for a household 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 petrol pump.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away then keep your mind on the petrol pump.
- Add-on devices are available for vehicles without one, and some diesels come with a filler that won't accept a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Stop the moment you notice. Less petrol inside your tank means a weaker mixture. It does not change what to do next, which is still not to fire it up.
Put petrol in a diesel in Myddyn-fych already?
Short and simple, then, is the order of things. Don't start the car, and don't turn the ignition on. Yet at the forecourt, at Tesco or anywhere else? Ask the staff to help you roll the car clear of the petrol pump. Then call 0333 366 0103 and tell us what got in, about how much, and if it has run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a different fault — Myddyn-fych has a page all for it.
What makes one Myddyn-fych petrol in a diesel task cost more than the next
Four different tasks lie behind the four scenarios above — which is why there's no fair single quote. Mostly, your cost shifts with which one you are in. Next it's the proportion — how much petrol was put in against how much your tank takes — and then where your car is and whether a technician can reach it safely.
Ahead of any quote, not after, we ask three questions: the fuel that was put in, its amount, and whether it's run. That's why. Those answers are what change a range into one firm number.
About Myddyn-fych and its setting
Myddyn-fych is a locality situated on the banks of a river in Carmarthenshire, with an elevation of around 43 metres. Myddyn-fych lies near the communities of Tir-y-dail and Penybanc, and is approximately 12.9 miles from Swansea. Myddyn-fych has a population of around 1215 people, with semi-detached housing being the predominant type. Myddyn-fych is located in a region of south Wales that has been shaped by its industrial and agricultural heritage.
Across Carmarthenshire and around Myddyn-fych: fuel drain cover
Petrol in diesel jobs around Myddyn-fych — part of the SA postcode area — go to vans that also cover the places about it, Tir-y-dail, Ammanford and Penybanc included. A forecourt, a supermarket car park, a lay-by or your own drive are all places our engineers drain, and your car does not need to move to us.
At the pump around Myddyn-fych, still?
The best place there is, then — that is where you are. Keep it off. Call.