How Worried Should You Be? Petrol in a Diesel Car in Overtown
Probably less than you are now — as long as nobody has started it. "Have I ruined it?" is the first question everyone in Overtown asks, and the truthful answer is generally no, since petrol left in a diesel tank hurts nothing till it's dragged through your fuel system — by ignition priming, by your starter, or by being driven. Petrol in Diesel is who to call, with the motor left off, and so it stays that way. The rest of this page explains what petrol actually 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 the motor
On its way through a motor, diesel has two tasks. It lubricates to begin with, and only then does it burn. Very fine tolerances go into your injectors and the high-pressure pump, and just your diesel running through keeps those surfaces from grinding together.
Badly at the first, not at all at the second: that's petrol. The clattering comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the system hinges on, and any pump running on such a mixture is wearing itself.
The shape of the problem is plain once you put those together. It is movement that causes the harm, not contact. Any tank with petrol in it is a fuel issue. A pump that has been running on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Petrol in a diesel in Overtown: how bad is it? Four situations
Filled up, and not started: nothing beats it. Being at a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With that petrol held inside your tank alone, it is cleared and purged on the spot, and nothing more is needed.
Ignition on, or started for a moment. With your system primed, your lines and filter already hold petrol that came from your tank. Drain, flush, deal with the filter: still usually simple.
The pump now worked a couple of miles on weakened fuel — that is what driving the vehicle does. How hard your car was driven counts as much as how far, and the work covers the tank, the fuel lines, your filter and clean fuel through the whole circuit. A school run to Wroughton Infant School is one matter. Any miles on the M4, under 3 miles from Overtown, means the engine working hard throughout, and a run to Bath, under 50 miles away, is a very different job too.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone ragged. What you are hearing is the engine reporting fuel that no longer runs like diesel. Whether it's the verge on Overtown Lane, a lay-by or a side road, stop there and leave it. The fuel drain and flush still come first, and they deal with it: if a vehicle is pulled over soon, long-term damage is very unusual.
What Overtown people get told about petrol in a diesel — and the myths in it
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Topping up takes out nothing; it gives you a bigger tank of the same mix. A diesel fuel system does not accept petrol by percentage in the way that advice presumes.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. Protection matters more on modern diesels, not less, since their fuel passes through finer parts at higher pressure.
Myth: "If it starts and drives, there is no harm done." This is the one that fools motorists. Diesel in a petrol motor generally means a motor that will not run: the motorist stops, and so does the damage. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump wears. Fine and running are not the same thing.
Myth: "Add some two-stroke oil and drive it home." It is an outdated workaround for a different problem. It does not put back what petrol has weakened, and that petrol is still in that tank later on.
Myth: "Drain the tank yourself and you're sorted." After the motor has run, some of the petrol is no longer in that tank: it is in the fuel filter and the fuel lines, and it goes right back through the pump at the next start. Emptying petrol into a can by the roadside is also really risky.
How petrol ends up: petrol in a diesel
A careless moment is rarely the cause, and no one means to do it. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol vehicle at all. The forecourt makes it simple, and the slip runs one way.
It happens when habit and your car stop matching. 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. A rushed fill on the way to Swindon with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: exactly when it takes place. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
Overtown drivers: how to avoid petrol in a diesel next time
- Green for unleaded and black for diesel is normal in the UK — but not on every forecourt. Trust the label on the petrol pump, not the colour.
- In a motor you don't know, look inside the flap over your filler or at the cap before the first fill: plenty of vehicles state the fuel there.
- Mark your key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It sounds silly and it works.
- Tuck your phone away. This is an easy mistake to make while you are thinking about something else.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- Stop as soon as you notice. Less petrol in the tank means a thinner mix. It does not change what to do next, which is still not to fire it up.
Put petrol in a diesel around Overtown already?
In that case, there's just a short order of things. Leave it unstarted, with the ignition off as well. Yet at the forecourt, at Esso or anywhere else? Ask the staff to help you push it away from the petrol pump. Next, 0333 366 0103. We will ask what went in, roughly how much, and if it has been run.
Corrosion and deposits are the problem with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and read its own Overtown page.
One petrol in a diesel job in Overtown costs more than another. Why?
The four scenarios above are four separate tasks, so no single price for this would be honest. Chiefly, the cost shifts with which one you're in. Two things come after that: the petrol that got in as a proportion of what your tank takes, then the spot the vehicle is in and whether a technician can reach it safely.
Ahead of any quote, not after, come three queries: the fuel that got in, the quantity, and whether it has run. That is why. The replies change a range into a straight figure.
About Overtown
Overtown is a small suburban area in Wiltshire, situated inland at an elevation of 186 metres. Overtown lies near the villages of Hodson, Elcombe, and Wroughton, and is approximately 26.5 miles from the city of Bath. Overtown has a population of around 608 people, with semi-detached housing being the predominant type in the area. Overtown is also within commuting distance of London, being around 71 miles to the west of the capital.
Fuel drain cover around Overtown and across Wiltshire
Petrol in diesel call-outs around Overtown — part of the SN postcode area — go to vans that also cover the places round it, Hodson, Elcombe and Wroughton among them. No need to bring the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places we drain.
Still at the petrol pump in Overtown?
In that case, you could not be in a better place. Keep it off. Phone.