Darrington: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, provided it has not been started. Until the ignition primes your pump, the starter cranks, or the vehicle is driven, petrol in a diesel tank just waits there and does nothing. Which makes the honest reply to the first Darrington question — "have I wrecked it?" — usually no. Keep it like that: leave the motor off then ring Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and the way to make sure you never do it again.
Petrol in a diesel: what does it do to your engine?
Diesel does two tasks on its way through a motor. It lubricates to begin with, and after that does it burn. Very fine clearances go into the fuel injectors and the high-pressure pump, and only the diesel running through stops those surfaces grinding together.
The second job petrol doesn't do at all, and the first it does poorly. The knocking comes from petrol being designed 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 protection your system rests on, and any pump working on that mixture is wearing itself.
The shape of the problem is clear once you put those together. It is movement that does the harm, not contact. Petrol in a tank is a fuel fault. The start of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with your fuel to your injectors downstream.
Darrington, petrol in a diesel: four situations, from mild to significant
The best case there is: filled up, never started. Being at a forecourt is what makes this the case: elsewhere, your car has been driven there to begin with. With that petrol kept in the tank alone, it is emptied and rinsed right where it stands, and nothing more is needed.
A brief spell of running, or just your ignition on. Petrol has left your tank and got to the fuel filter and the lines, because the fuel system has been bled. Usually nothing more than emptying, cleaning and sorting your filter, so still simple.
Driven a few miles. Now the pump has spent those miles working on thinned fuel. The work is the tank, the lines, the fuel filter and clean fuel through the entire system, and how hard the car was driven matters as much as how far. Short trips, such as the school run to Darrington Church of England Primary School, are one matter. A run as far as Wakefield, under 10 miles away, is a very different task. So is any miles on the A1(M), under a mile from Darrington, where the engine has been running hard the whole time.
Driven until it complained. Clattering, a ragged idle, smoke, a throttle that has gone soft. The engine is telling you the fuel is no longer behaving like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Philip's Lane. Long-term damage is very unusual if a car is stopped soon, and the drain and flush that still go first take care of it.
Myths Darrington motorists hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. A diesel fuel system doesn't tolerate petrol by percentage in the way that advice assumes.
"Modern diesels can handle a little petrol" — a myth, and nearer the opposite. Smaller parts and higher pressure are the way a modern diesel runs its fuel, and that makes the lubrication count more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there is no damage done." Diesel in a petrol motor generally leaves a motor that won't run: the motorist stops, and so does the harm. While the pump wears, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. Being able to run is not the same as being fine.
An outdated workaround for a separate problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol diluted is put back by it — and later, your tank still holds the petrol.
Once the engine has run, part of the petrol sits in the fuel filter and the lines, not your tank — and the next start sends it right back through your pump. So the myth "drain the tank yourself and you're sorted" doesn't stand up. On top of that, petrol emptied into a can by the road is truly hazardous.
How does petrol in a diesel occur?
Carelessness is seldom the cause, and no one means to do it. A diesel nozzle mostly will not fit a petrol car, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error simple, and only in that direction.
Habit and the car getting out of step is when it happens. Any car that's new to you — a hire car, on loan as a courtesy car, or just bought. One petrol and one diesel on the drive of the same household. A forecourt you know, only with its pumps arranged differently. Fuelling up in a rush on the way to Pontefract Baghill, with a train to catch. A new-to-you diesel Skoda Octavia, its first fuelling, and a driver used to petrol: exactly when it takes place. Your hand does what it has always done when you add rain, a phone call or a back seat full of kids.
Darrington drivers: how to avoid petrol in a diesel next time
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Check the pump's label; the colour is just a hint.
- In a vehicle you do not know, look inside the flap over the filler or at the cap before the first fill: plenty of vehicles print the fuel type there.
- One of each in the house? Mark the key to your diesel — a coloured fob, a sticker — since meaning 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.
- Mistakes like this are straightforward to make whilst your mind is on something else, and so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to block a petrol nozzle, and add-on devices are available for vehicles without one. They are a safety net, not a reason to stop reading the petrol pump.
- Stop as soon as you notice. Less petrol inside the tank makes a weaker mixture. It does not change what to do next, which is still not to crank it.
Petrol already in a diesel around Darrington? Start here
Then the order of things is short. Leave it unstarted, with your ignition off too. If you are still on the forecourt — Applegreen or anywhere else — ask the staff to help you push the car clear of the petrol pump. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it has been run.
Corrosion and deposits form the trouble with AdBlue, where petrol brings lost protection. So if it was AdBlue, say so — and see its own Darrington page.
One petrol in a diesel job in Darrington costs more than another. Why?
The four situations above are four separate jobs, so no single price for this would be fair. Chiefly, your cost shifts with which one you are in. Two things come after that: the petrol that was put in as a proportion of what your tank takes, then the spot the vehicle is in and whether a technician can reach it safely.
Three questions come first, before quoting, rather than after — what was put in, how much, has it run — and that is the reason. Those answers turn a range into a straight figure.
About Darrington
Darrington is a small village in West Yorkshire, situated inland at an elevation of around 40 metres, and is located approximately 9 miles from Wakefield. Darrington has a population of around 578 people and is characterised by predominantly detached housing. Darrington is part of a network of rural settlements that include nearby Carleton, Stapleton, and other local communities.
Fuel drain cover across West Yorkshire, Darrington included
Our vans answering petrol in diesel call-outs in Darrington, in the WF postcode area, equally work the locations near it, Carleton, Eastbourne and Stapleton included. The vehicle does not need to come to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the petrol pump around Darrington?
Then, you couldn't be in a better place. Leave it switched off, and ring.