New Shildon: Petrol in a Diesel Car? How Worried to Be
Far less than you probably are, provided it hasn't been started. Petrol sitting in a diesel tank does nothing to the motor till something pulls it through the system — the ignition priming the pump, your starter, or the drive itself. So the truthful answer to the first question everyone in New Shildon asks, "have I wrecked it?", is usually no. Petrol in Diesel is who to call, with your engine kept off, and so it stays that way. Further down, this page sets out what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to the engine?
Diesel has two jobs on its way through a motor. Before it combusts, it lubricates — and then it burns. Very fine clearances go into the fuel injectors and the high-pressure pump, and only the diesel flowing through stops those surfaces grinding together.
Of these two jobs, petrol handles the first badly and the second never. The knocking comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication the fuel system hinges on, and any pump running on such a mix is wearing itself.
Taken together, they make clear the shape the issue takes. It's circulation that causes the harm, not contact. All a tank with petrol in it amounts to is a fuel problem. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the injectors further on.
How serious is petrol in a diesel? Four scenarios our engineers see in New Shildon
Filled up, not once started. The best case there is. Being on a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol held in your tank alone, it's drained and flushed right where it stands, and nothing more is needed.
Ignition on, or started for a second. Petrol has left that tank and reached your filter and the fuel lines, since your system has been primed. Still generally easy: drain, flush, and the filter sorted.
The pump has worked a few miles on weakened fuel — that's what driving the vehicle meant. Mileage is only half of that; how hard it was driven counts just as much. Either way the work includes the tank, the fuel lines, the fuel filter and clean fuel through the entire system. Short trips, like the school run to Timothy Hackworth Primary School, are one matter. Any miles on the A1(M), under 5 miles from New Shildon, means your engine has worked hard throughout, and a run to Durham, under 15 miles away, is a very different job as well.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. The engine is telling you the fuel is no longer behaving like diesel. Pull up wherever you are — the verge on B6282, a lay-by, a side street — and leave it there. Lasting damage is very rare when a car is stopped quickly, and the fuel drain and flush that still come first deal with it.
Myths New Shildon people hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing comes out when you top up — the tank simply holds more of the same blend. Percentage isn't how a diesel fuel system tolerates petrol, whatever that advice assumes.
If anything, the opposite holds. Myth: "A current diesel can cope with a bit of petrol." At higher pressure, through finer components: that's how a current diesel moves its fuel, and so the lubrication matters for more, not less.
This is the one that fools people. Myth: "If it starts and drives, there's no damage done." Feed diesel to a petrol motor and it usually won't run, and so the motorist stops — and the damage stops with them. Feed petrol to a diesel and it generally starts, idles and drives away as if nothing has happened — all the while its pump wears. Being able to run isn't the same as being fine.
Not so: a two-stroke additive makes it safe to drive home. It was an old fix, supposed for another fault. What petrol has thinned remains thinned, and that petrol stays inside your tank anyway.
The next start sends petrol back round the pump from the lines and the fuel filter, where some of it ends up after the motor has run. That's why draining your tank yourself doesn't leave you sorted — a myth. Besides, petrol cleared into a can by the road is genuinely dangerous.
How petrol ends up: petrol in a diesel
It is rarely carelessness, and no one does it on purpose. A diesel nozzle generally will not fit a petrol car, but the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and only in that direction.
The moment habit stops matching the vehicle is the moment it takes place. Courtesy car, hire car, or a car that is brand new. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. Rushing for a train outside Shildon and fuelling up en route. A new-to-you diesel Renault Megane, its first fuelling, and a motorist used to petrol: exactly when it occurs. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
New Shildon motorists: how to avoid petrol in a diesel next time
- Check the pump, not the colour. In the UK unleaded handles are normally green and diesel black, but not on every forecourt. The label is what counts.
- In a car you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of motors print the fuel there.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a house with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump. It sounds silly and it does the trick.
- 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.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to block a petrol nozzle, and aftermarket devices exist for the rest. Treat it as a backstop, then keep reading the petrol pump.
- Less petrol means a weaker mix, and so stop as soon as you notice — though remembering that your next step is unchanged. It is still not to start the car.
Petrol already in a diesel around New Shildon? Begin here
Short and simple, then, is the order of things. Leave it unstarted, with the ignition switched off too. If you are still at the forecourt — JET or anywhere else — ask the attendants to help you roll the car away from the petrol pump. Ring 0333 366 0103 next, with three facts — your fuel, the approximate volume, and if it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a separate issue — New Shildon has a page just for it.
New Shildon petrol in a diesel tasks: why one costs more than another
An honest single quote does not exist here: four scenarios, four separate jobs. Chiefly, the cost moves with which situation you are in. After that it is the ratio — how much petrol got in against how much your tank takes — and after that where the car is and whether a technician can reach it safely.
What was put in, how much, and whether it's run — three queries our technicians ask before quoting, not after, for exactly that reason. The replies change a range into a straight figure.
About New Shildon itself
New Shildon is a suburban area in County Durham, situated approximately 10.9 miles from the city of Durham. New Shildon lies inland, with an elevation of around 126 metres, and is located near the communities of Shildon, Sunnydale, and Eldon Lane. New Shildon has a population of around 2755 people, predominantly residing in terraced housing.
New Shildon and Durham: where our fuel drain cover reaches
Shildon, Sunnydale and Eldon Lane are among the locations near New Shildon that the same teams work, answering petrol in diesel calls across New Shildon's DL postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations our technicians drain, and the car does not need to come to us.
New Shildon: still at the pump?
Then you're in the best place there is. Keep it off. Call.