Wyatts Green: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — provided nobody has started the car. Till your ignition primes your pump, the starter turns, or the car is driven, petrol in a diesel tank just rests there and does nothing. Which makes the honest reply to that first Wyatts Green query — "have I wrecked it?" — normally no. Leave your motor off then call Petrol in Diesel — that is how you keep it like that. The rest of this page covers what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you a second time.
What petrol in a diesel does to your engine
Diesel has two jobs on its way through a motor. It lubricates first, and after that does it burn. Extremely fine gaps are built into your injectors and the high-pressure pump, and just the diesel running through stops their surfaces grinding together.
Of these two tasks, petrol handles the first badly and the second not at all. A pump running on a petrol blend is wearing itself out, because petrol is runnier than diesel and strips out the protection your fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that is where the rattling comes.
Put these together and the shape of the trouble is clear. Contact does not do the harm — movement does. A tank with petrol in it is a fuel fault. The beginning of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with the fuel to your injectors beyond it.
Four situations our engineers see around Wyatts Green: how serious is petrol in a diesel?
Filled but not once started — as good as it gets. Being at a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol kept inside the tank alone, it's emptied and flushed on the spot, and nothing more is needed.
A moment's running, or just the ignition on. Once primed, the system has drawn petrol from the tank up to the fuel filter and your lines. Normally little more than clearing, flushing and sorting your filter, so still straightforward.
Those few miles on the road were your pump labouring on fuel diluted by petrol throughout. Tank, lines, filter, then fresh fuel put through the entire circuit: that is the work, and the way the vehicle was driven matters as much as the distance. Short trips, like the school run to Doddinghurst Infant School, are one thing. Any miles on the M25, under 5 miles from Wyatts Green, means your engine working hard throughout, and a run to Chelmsford, under 10 miles away, makes a very different job as well.
Driven on till it protested — clattering, smoke, a lumpy idle, a dead throttle. The fuel is not acting like diesel any more, and your motor is telling you. Whether it's the verge on Wyatt's Green Road, a lay-by or a side road, stop where you are and leave it. A car stopped quickly very seldom has permanent damage, as the fuel drain and the flush-through, which still go first, deal with it.
Myths Wyatts Green motorists hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing comes out when you top up — that tank simply carries more of the same blend. A diesel fuel system doesn't tolerate petrol by percentage in the way that advice supposes.
Myth: a modern diesel copes with a bit of petrol. If anything, the opposite. At higher pressure, through finer components: that's how a current diesel moves its fuel, so the protection counts for more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools drivers. The motorist of a petrol motor fed diesel normally stops, since it will not run, and the harm stops there. Feed petrol to a diesel and it generally starts, idles and drives away like nothing happened — all the while its pump wears. Fine and running are not the same thing.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct fault. It doesn't put back what petrol has weakened, and that petrol is still inside that tank after that.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol sits in the filter and lines, waiting to go right back through the pump at the next start. Also, a can of petrol drained at the roadside is genuinely dangerous.
How does petrol in a diesel occur?
It's seldom carelessness, and nobody does it on purpose. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle generally will not go into a petrol car at all. So the slip runs one way.
When habit and your car stop matching, it takes place. Courtesy car, hire car, or a vehicle that's brand new. Two vehicles on one drive, one petrol, one diesel. Your normal forecourt, its pumps now in a different order. Racing for a train outside Shenfield and filling up en route. A new-to-you diesel Renault Clio, its first fuelling, and a motorist accustomed to petrol: precisely when it happens. With rain, a call coming in, or children to deal with, your hand just does what it has always done.
Avoiding petrol in a diesel next time you fill up around Wyatts Green
- A green handle for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Go by the label on the petrol pump, not the colour.
- In a vehicle you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of cars state the fuel type there.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, for a household with one of each.
- Before the nozzle comes off the pump the first time you fill a hired or new vehicle, say "diesel" out loud. Silly, yes, but it works.
- Whilst you're thinking about something else, this is an easy mistake to make — so put the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to refuse a petrol nozzle, and add-on devices exist for cars without one. They are a safety net, not a reason to stop checking the petrol pump.
- Stop the moment you notice. Less petrol in your tank means a thinner mixture. It doesn't change what to do next, which is still not to fire it up.
Wyatts Green: already put petrol in a diesel?
Then the order of things is short. Don't switch the ignition on, and don't fire it up. If you are still on the forecourt — BP or anywhere else — ask the staff to help you roll the vehicle clear of the petrol pump. Then phone 0333 366 0103 and tell us what went in, roughly how much, and if it's run.
Corrosion and deposits are the trouble with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and read its own Wyatts Green page.
Wyatts Green petrol in a diesel jobs: why one costs more than another
There's no fair single quote for this, because the four situations above are four different jobs. Which of them you are in is mostly what shifts the cost. After that it's the ratio — how much petrol got in against how much that tank holds — and after that where your car is and whether our van can reach it safely.
Before any quote, not after, come three questions: the fuel that went in, the quantity, and if it's run. That is why. A range becomes a straight figure when the replies are in.
About Wyatts Green, briefly
Wyatts Green is a small village in Essex, situated inland at an elevation of 83 metres, and is located near the larger city of Chelmsford. Wyatts Green has a population of around 963 people and is characterized by predominantly detached housing. Wyatts Green is close to nearby places such as Doddinghurst, Peartree Green, and Hook End, and is about 21.9 miles from London.
Across Essex and around Wyatts Green: fuel drain cover
Doddinghurst, Peartree Green and Hook End are among the spots around Wyatts Green that the same teams work, answering petrol in diesel jobs across Wyatts Green's CM postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots our engineers drain, and the vehicle doesn't need to move to us.
Wyatts Green: still at the petrol pump?
No position is better: that's where you now are. Ring, and leave it turned off.