Great Preston: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, provided it has not been started. "Have I wrecked it?" is the first thing anyone in Great Preston asks, and the truthful answer is normally no, because petrol left in a diesel tank hurts nothing until it is drawn through the fuel system — by ignition priming, by the starter, or by being driven. Leave your motor off and ring Petrol in Diesel — that keeps it that way. Keep reading for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and ways to make sure you don't do it again.
What petrol in a diesel does to the motor
Diesel has two jobs on its way through an engine. Before it ignites, it protects — and then it combusts. Very fine tolerances are built into the fuel injectors and the high-pressure pump, and just your diesel flowing through keeps those surfaces from grinding together.
Poorly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump on that mixture wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is where you get the knocking.
Put these together and the shape of the issue is clear. Not contact but movement is what causes the damage. All a tank with petrol in it amounts to is a fuel problem. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to your injectors further on.
How bad is petrol in a diesel? Four situations our technicians see in Great Preston
Fuelled but never started — as good as it gets. At a forecourt, and really only there, the petrol is still confined to the tank — since anywhere else your car was driven to get to it. The task is emptying and rinsing on the spot.
A moment's running, or merely your ignition on. Petrol has left your tank and reached your filter and the fuel lines, since the system has been bled. Still generally straightforward: drain, flush, and your filter dealt with.
Driven a few miles. Now the pump has spent these miles labouring on weakened fuel. How hard the vehicle was driven counts as much as how far, and this work covers your tank, the fuel lines, the fuel filter and fresh fuel through the entire system. On the school run to Great Preston VC CofE Primary School, the distance is small. Driving as far as Wakefield, under 10 miles away, makes a very different job — as does any distance on the M1, under 3 miles from Great Preston, with the motor working hard all the way.
Driven until it complained. Clattering, a lumpy idle, smoke, a throttle that has gone soft. The fuel is not behaving like diesel any more, and the motor is telling you. Pull up wherever you are — the verge on Whitehouse Lane, a lay-by, a side street — then leave it where it is. What comes first is still the drain and flush-through, and that deals with it, with long-term damage very uncommon if a car is stopped quickly.
What Great Preston drivers get told about petrol in a diesel — and the myths in it
Myth: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. That advice supposes a diesel fuel system handles petrol by percentage. It doesn't.
Myth: a newer diesel copes with a bit of petrol. If anything, the reverse. At higher pressure, through smaller parts: that's how a modern diesel handles its fuel, and so the protection counts more, not less.
"It starts, it drives, so there is no harm" — the myth that catches most drivers than any other. Diesel in a petrol motor normally means a motor that will not run: the driver stops, and so does the damage. A diesel fed petrol usually starts, ticks over and drives away as if nothing has happened, whilst the pump wears. 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 distinct fault. What petrol has weakened stays weakened, and that petrol stays in your tank anyway.
Myth: "Drain the tank yourself and you are sorted." After the motor has run, some of that petrol is no longer in that tank: it is in your filter and the lines, and it goes straight back through the pump at your next start. Also, a can of petrol drained at the roadside is truly hazardous.
How it happens: petrol in a diesel
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol vehicle at all. The forecourt makes it simple, and the slip runs one way.
It takes place when habit and your car stop matching. A vehicle that is new to you — a hire car, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Rushing for a train outside Woodlesford and fuelling up en route. Exactly the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. Add a back seat full of children, a phone call or rain, and habit takes over.
Next time you fill up in Great Preston: preventing petrol in a diesel
- Read the pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on each forecourt. The label is what counts.
- Plenty of vehicles state the fuel inside the filler flap or on the cap, so check it on the first fill in a motor you do not know.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key if a house has one of each. So mark it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It seems daft and it does the trick.
- While you're thinking about something else, this is an easy mistake to make — so put your phone away.
- Add-on devices exist for motors without one, and some diesels come with a filler that won't accept a petrol nozzle. Helpful — but a backstop at best, never a reason to stop checking the label.
- Noticing it halfway? Stop there and then. A weaker mix results from less petrol inside the tank, yet the next step remains the same: don't start it.
Petrol already in a diesel in Great Preston? Start here
In that case, there is just a short order of things. Starting it is out, and so is turning on the ignition. Still on the forecourt, at Oakdale Garage or anywhere else? Ask the staff to help you roll the vehicle away from the petrol pump. What was put in, roughly how much, and whether it has run: tell us that when you call 0333 366 0103.
If it was AdBlue instead of petrol, say so. That is a different fault — corrosion and deposits and not lost lubrication — and it has its own page for Great Preston.
Why one petrol in a diesel job in Great Preston costs more than another
Four different jobs lie behind the four situations above — which is why there's no fair single price. What shifts your cost is mostly which of them you're in. Next it's the share — how much petrol was put in against how much the tank takes — and after that where the vehicle is and whether a van can reach it safely.
Three queries come first, before quoting, rather than after — what went in, how much, has it run — and that is the reason. With the replies, there is a straight figure instead of a range.
About Great Preston and its setting
Great Preston is a village in West Yorkshire, situated on the riverside at an elevation of 62 metres, with semi-detached housing being the predominant type of accommodation. Great Preston lies approximately 6.9 miles from Wakefield and 164.5 miles from London, making it a relatively small community in the region. Great Preston is surrounded by nearby places such as Woodend, Little Preston, and Kippax, and has a population of around 829 residents. Great Preston benefits from its location in the Yorkshire and the Humber region, with its riverside setting providing a unique character to the village.
Fuel drain cover across West Yorkshire, Great Preston included
Our vans answering petrol in diesel jobs around Great Preston, in the LS postcode area, equally work the places around it, Woodend, Little Preston and Kippax among them. The vehicle doesn't need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the pump around Great Preston?
Then you're in the best place there can be. Phone, and keep it switched off.