How Worried Should You Be? Petrol in a Diesel Car in Wattstown
Probably less than you are now — provided nobody has started it. "Have I wrecked it?" is the first question anyone around Wattstown asks, and the honest answer is usually no, since petrol resting in a diesel tank harms nothing until it's drawn through your fuel system — by ignition priming, by the starter, or by being driven. To leave the car like that, call Petrol in Diesel and leave your engine switched off. What petrol actually does to a diesel, how to gauge how far it's travelled, and how to keep it from happening a second time: that is the remainder of this page.
Inside your engine: what petrol in a diesel does
Diesel has two jobs on its way through an engine. It combusts, and before it combusts it lubricates. The high-pressure pump and the injectors are built to extremely fine gaps, and the diesel passing through them is what keeps those surfaces from wearing against one another.
Of those two jobs, petrol handles the first poorly and the second not at all. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection your system hinges on, and any pump working on such a blend is wearing itself.
The shape of the trouble is clear once you put those together. It is circulation that causes the harm, not contact. Petrol in the tank is a fuel fault. Once the pump has been working on that petrol, a mechanical problem has begun: whatever is shed by a pump that is wearing down travels onward to the injectors with the fuel.
Wattstown, petrol in a diesel: four situations, from mild to serious
Filled up, not once started. The best case there can be. Being on a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With that petrol held in your tank alone, it's cleared and cleaned on the spot, and nothing more is needed.
Started for a second, or only your ignition on. Once primed, your system has drawn petrol from your tank up to the filter and your lines. That's normally still a straightforward task — a drain, a flush, and the fuel filter dealt with.
A few miles driven, and the pump has spent each of them running on diluted fuel. Tank, lines, filter, then clean fuel put through the entire system: that is this work, and the way your car was driven matters as much as the mileage. Driving the children to the local primary school is one sort of trip. Any miles on the M4, under 10 miles from Wattstown, means your engine working hard throughout, and a run to Cardiff, under 15 miles away, is a very different task as well.
Driven on till it complained — knocking, smoke, an uneven idle, a soft throttle. That's the motor telling you its fuel has stopped behaving like diesel. Pull up where you are — on the verge on Aberllechau Road, at the kerb, down a side road — and do not move it. Long-term damage is very unusual when a car is stopped soon, and the fuel drain and flush-through that still come first sort it out.
Wattstown motorists and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed by topping up — you're left with a bigger tank, still the same mix. The assumption behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. A modern diesel runs its fuel through finer parts at higher pressure, which makes the lubrication count more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no damage done." Feed diesel to a petrol motor and it generally won't run, so the motorist stops — and the harm stops with them. While the pump grinds, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Running doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct problem. None of what petrol weakened is put back by it — and later, the tank still holds the petrol.
The next start sends petrol back round your pump from your lines and the filter, where some of that ends up after your engine has run. That is why draining the tank yourself doesn't leave you sorted — a myth. It's also really risky to drain petrol into a can at the roadside.
How it happens: petrol in a diesel
Nobody does it on purpose, and it is seldom carelessness. One way only, because of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one mostly won't fit a petrol car. That is how the forecourt makes it simple.
Habit and the car falling out of step is when it occurs. Hire cars, courtesy cars, and vehicles that are new to you. Households running one of each, petrol and diesel. Your ordinary forecourt, its pumps now in a different order. A train to catch, and a rushed fill en route to Dinas Rhondda. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist accustomed to petrol: exactly when it happens. The hand does what it has always done once you add rain, a phone call or a back seat full of kids.
Preventing petrol in a diesel next time you fill up in Wattstown
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Read the pump's label; the colour is only a hint.
- In a vehicle you do not know, look inside the flap over the filler or at the cap before your first fill: many vehicles state the fuel there.
- Mark the key. In a house 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 leaves the petrol pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Daft, yes, 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 petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to block a petrol nozzle, and add-on devices are available for motors without one. They are a safety net, not a reason to stop reading the petrol pump.
- Stop the moment you realise. Less petrol in your tank makes a weaker mix. It doesn't change what to do next, which is still not to fire it up.
Wattstown: already put petrol in a diesel?
In that case, there is only a short order of things. Do not switch your ignition on, and don't crank it. Still at the forecourt, at Shell or anywhere else? Ask the attendants to help you roll the vehicle away from the pump. Next, 0333 366 0103. We'll ask what went in, roughly how much, and if it has been run.
Corrosion and deposits form the trouble with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and read its own Wattstown page.
One petrol in a diesel job in Wattstown costs more than another. Why?
There is no fair single price for this, because the four situations above are four separate tasks. What shifts the cost is mostly which of them you're in. Next it is the proportion — how much petrol was put in against how much the tank takes — and after that where your car is and whether a van can reach it safely.
That is why our technicians ask three queries before pricing instead of after: what got in, how much, and whether it has run. Their answers are what change a range into one firm number.
About Wattstown
Wattstown is a small village in Rhondda Cynon Taf, situated on the riverside in south Wales. Wattstown has a population of around 1105 people and is characterized by its predominantly terraced housing. Wattstown is located near other villages such as Pontygwaith, Ynyshir, and Stanleytown, and is approximately 14.9 miles from Cardiff. Wattstown sits at an elevation of 136 metres, in a valley setting.
Across Rhondda Cynon Taf and around Wattstown: fuel drain cover
Wattstown waits in the CF postcode area, and our vans that answer petrol in diesel call-outs there work the locations around it as well — Pontygwaith, Ynyshir and Stanleytown among them. We drain wherever your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
In Wattstown and still at the petrol pump?
Then you're in the best spot there is. Phone, and leave it switched off.