Should You Worry? Petrol in a Diesel Car in Rushy Green
Far less than you probably are, if it has not been started. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through your fuel system — the ignition priming the pump, the starter, or the drive on its own. So the truthful answer to the first question anyone in Rushy Green asks, "have I ruined it?", is usually no. Leave the motor off and call Petrol in Diesel — that keeps it that way. The rest 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 doesn't happen to you a second time.
What petrol in a diesel does to your engine
Diesel has two tasks on its way through an engine. It lubricates first, and only then does it burn. What stops the surfaces inside the high-pressure fuel pump and the fuel injectors from wearing down against each other is your diesel passing through them — they're designed to extremely fine tolerances.
Poorly at the first, not at all at the second: that's petrol. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump running on the blend to wear itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the knocking.
The shape of the problem is plain once you put those together. The harm is done by circulation, not by contact. Petrol in the tank is a fuel fault. After the pump has been working on that petrol, a mechanical fault has begun: anything shed by a pump that is wearing is carried downstream to the injectors with the fuel.
Rushy Green, petrol in a diesel: four situations, from mild to major
Fuelled up, not once started. The best case there can be. On a forecourt, and truly only there, that petrol is still confined to that tank — since everywhere else your car was driven to reach it. The task is draining and flushing on the spot.
A moment's running, or merely the ignition on. Once primed, the fuel system has drawn petrol from the tank up to the filter and your lines. Drain, flush, deal with your filter: still normally easy.
The pump has spent a few miles on diluted fuel — that's what driving the car does. Tank, lines, filter, then fresh fuel put through the whole circuit: that's this work, and the way your car was driven counts as much as the miles. Short trips, such as the school run to Ringmer Primary and Nursery School, are one thing. A run as far as Brighton and Hove, under 15 miles away, is a very different job. So is any miles on the M23, under 25 miles from Rushy Green, where your engine has been labouring hard throughout.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. That is your motor telling you its fuel no longer is acting like diesel. Pull up where you are — on the verge on Greater Paddock, at the kerb, down a side road — and don't move it again. The drain and flush still come first, and they deal with it: if a car is stopped quickly, long-term damage is very rare.
What Rushy Green motorists get told about petrol in a diesel — and the stories in it
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you're left with a fuller tank, still the same mixture. Percentage is not how a diesel fuel system copes with petrol, however much that advice assumes.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." Lubrication matters more on newer diesels, not less, since their fuel passes through smaller parts at higher pressure.
"It starts, it drives, so there is no harm" — the myth that catches more motorists than any other. Feed diesel to a petrol motor and it normally will not run, so the driver stops — and the damage stops with them. Feed petrol to a diesel and it normally starts, ticks over and drives away like nothing happened — all the while its pump wears. Fine and running aren't the same thing.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different issue. What petrol has thinned remains weakened, and the petrol stays inside that tank regardless.
The next start sends petrol back round your pump out of the fuel lines and your filter, where some of it sits once the engine has run. That is why a DIY tank drain does not sort it — a myth. Draining petrol into a can at the kerbside is also genuinely dangerous.
Why petrol in a diesel takes place at all
Nobody does it on purpose, and it is rarely carelessness. One way only, since of the nozzles: the smaller petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one generally will not fit a petrol car. That is how the forecourt makes it straightforward.
The moment routine stops matching the vehicle is the moment it occurs. Hire cars, courtesy cars, and motors that are new to you. Two cars on one drive, one petrol, one diesel. A well-known forecourt with the pumps in a different order. Rushing for a train outside Glynde and filling up en route. A new-to-you diesel Renault Megane, its first fuelling, and a driver used to petrol: precisely when it happens. With rain, a call coming in, or a car full of children to deal with, your hand simply does what it always has.
Preventing petrol in a diesel next time you fill up in Rushy Green
- 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, but not on each forecourt.
- Check the filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on the first fill in a motor you do not know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of meaning to remember, in a home with one of each.
- Before the nozzle comes off the pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Daft, perhaps, yet it does the trick.
- Tuck the phone away. This is an easy mistake to make while you are thinking about something else.
- Add-on devices are available for motors without one, and some diesels come with a filler that will not take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- The moment you notice, stop: less petrol in that tank makes a thinner mixture. What to do next does not change, though — still don't start the vehicle.
Rushy Green: already put petrol in a diesel?
The order of things is brief, then. Leave it unstarted, with your ignition off too. If you are still on the forecourt — Busy Bee Garage or anywhere else — ask the attendants to help you push it clear of the pump. What was put in, roughly how much, and whether it's run: tell us that when you ring 0333 366 0103.
Corrosion and deposits form the issue with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and see its own Rushy Green page.
One petrol in a diesel task in Rushy Green costs more than another. Why?
The four scenarios above are four different jobs, so no single quote for this would be fair. Chiefly, the cost shifts with which one you are in. Beyond that it's the ratio — how much petrol went in against how much your tank takes — and then where the car is and whether a technician can get to it safely.
That's why our technicians ask three queries before pricing rather than after: what went in, how much, and whether it's run. Given the replies, there is a straight figure rather than a range.
About Rushy Green, for a moment
Rushy Green is a locality in East Sussex, situated inland at an elevation of 17 metres, approximately 10 miles north of Brighton and Hove. Rushy Green lies near several other small settlements, including Ashton Green, Ringmer, and Broyle Side, and is characterized by its predominantly semi-detached housing stock. Rushy Green is also relatively close to London, being about 43 miles south-east of the capital. Rushy Green has a population of around 961 residents.
Rushy Green and East Sussex: where our fuel drain cover reaches
Our teams answering petrol in diesel calls around Rushy Green, in the BN postcode area, also work the spots around it, Ashton Green, Ringmer and Broyle Side among them. You need not bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
In Rushy Green and still at the pump?
The best position there is, then — that's where you are. Switched off it stays; then ring.