Ryelands: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less anxious than you likely are. "Have I wrecked it?" is the first question anyone around Ryelands asks, and the truthful answer is usually no, since petrol left in a diesel tank harms nothing till it's drawn through your fuel system — by ignition priming, by your starter, or by being driven. Leave your motor off then ring Petrol in Diesel — that keeps it that way. 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.
Inside the motor: what petrol in a diesel does
On its way through a motor, diesel has two tasks. It burns, and before it burns it lubricates. What keeps the surfaces inside your high-pressure pump and the injectors from wearing against one another is the diesel flowing through them — they are made to extremely fine clearances.
The second job petrol doesn't do at all, and the first it does poorly. The clattering comes from petrol being designed not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication your system rests on, and any pump working on that mixture is wearing itself.
The shape of the issue is plain once you put those together. The damage is done by movement, not by contact. Where that petrol is only in that tank, it's an issue of fuel, nothing more. A pump that has been working on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with the fuel to the injectors further on.
Petrol in a diesel in Ryelands: how serious is it? Four situations
Fuelled but not once started — the best it gets. That petrol is inside your tank and just that tank, and the job is a drain and a flush where the car sits. This is the one situation that can only really happen on a forecourt, since anywhere else your car has been driven to get there.
A moment's running, or just your ignition on. With your system primed, your lines and filter already contain petrol that came from your tank. Drain, flush, see to the filter: still usually simple.
A couple of miles driven, and your pump has spent every one of them working on diluted fuel. Tank, lines, filter, then clean fuel put through the whole system: that is this work, and the way the vehicle was driven matters as much as the mileage. A school run to Leominster Primary School is one thing. A run as far as Hereford, under 15 miles away, is a very different job. So is any distance on the M50, under 25 miles from Ryelands, where the motor has been running hard throughout.
Knocking, an uneven idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you the fuel is no longer acting like diesel. Leave it where it has stopped: a lay-by, a side street, the verge on Ryelands Road. The fuel drain and flush-through still come first, and they deal with it: if a car is stopped quickly, permanent damage is very rare.
Ryelands drivers and the petrol in a diesel myths they hear
False: topping up to full with diesel makes it fine. It does not. Nothing comes out when you top up — the tank simply holds more of the same blend. Percentage is not how a diesel fuel system tolerates petrol, whatever that guidance supposes.
If anything, the reverse holds. Myth: "A modern diesel can cope with a bit of petrol." At higher pressure, through more precise parts: that is how a newer diesel moves its fuel, and so the lubrication matters more, not less.
One myth that catches people off guard: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the damage stops with them. A diesel fed petrol generally starts, ticks over and drives away as if nothing has happened, while the pump grinds. Fine and running are not the same at all.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different problem. None of what petrol thinned is put back by it — and later, your tank still contains the petrol.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol lies in your filter and lines, ready to go straight back through the pump at the next start. Also, a can of petrol filled at the roadside is truly dangerous.
Petrol in a diesel: how does it take place?
On purpose? Never. Through carelessness? Rarely, if ever. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, while the diesel one mostly won't fit a petrol motor. That is how the forecourt makes it easy.
Routine and the car falling out of step is when it occurs. Courtesy car, hire car, or a motor that is new. Two vehicles on one driveway, one petrol, one diesel. The pumps in a different order on a familiar forecourt. Rushing for a train outside Leominster and filling up en route. Years of petrol cars behind you, a diesel Volkswagen Passat in front of you on the forecourt for its first tank — that's when. Add a back seat full of kids, a phone call or rain, and the hand takes over.
Ryelands drivers: how to prevent petrol in a diesel next time
- The label is what counts, and so read the pump instead of the colour: in the UK unleaded handles are usually green and diesel black, yet not on each forecourt.
- In a motor you don't know, look inside the flap over the filler or at the cap before the first fill: plenty of motors print the fuel there.
- One of each in the house? Mark the key to the diesel — a bright fob, a sticker — since intending to remember isn't enough.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It seems silly and it does the trick.
- While you're thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Some diesels come with a filler designed to refuse a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the pump.
- Noticing it halfway? Stop at once. A thinner mixture follows from less petrol in that tank, yet the next step stays the same: do not crank it.
Put petrol in a diesel around Ryelands already?
Then the order of things is brief. Do not turn your ignition on, and don't fire it up. Still on the forecourt, at Morrisons or anywhere else? Ask the staff to help you roll it away from the pump. Then phone 0333 366 0103 and tell us what was put in, about how much, and whether it has run.
Say so if it was AdBlue instead of petrol: it is a separate fault, with its own page for Ryelands, since AdBlue brings corrosion and deposits rather than lost lubrication.
Why one petrol in a diesel job around Ryelands costs more than another
The four scenarios above are four separate jobs, so no single quote for this would be fair. The situation itself does most of the work of moving the cost. The ratio matters next, meaning how much of the tank is petrol, followed by the location of your car and whether getting to it is safe for a technician.
Three queries come first, before quoting, instead of after — what was put in, how much, has it run — and this is the reason. A range becomes a straight figure when those answers are in.
About Ryelands, briefly
Ryelands is a small hamlet in Herefordshire, situated inland at an elevation of around 100 metres. Ryelands lies approximately 11 miles from Hereford and 122 miles from London, placing it in a rural setting with nearby places including Newlands and Leominster. Ryelands has a population of around 610 people, predominantly living in terraced housing. Ryelands is characterized by its quiet, residential atmosphere, typical of many small hamlets in the West Midlands region.
Ryelands and Herefordshire: where our fuel drain cover reaches
Ryelands rests in the HR postcode area, and our vans that answer petrol in diesel jobs there work the locations around it as well — Newlands, Leominster and Barons Cross among them. No need to move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots we drain.
At the pump around Ryelands, still?
The best position there is, then — that is where you are. Leave the vehicle switched off, then ring.