Petrol in a Diesel Car in Stapleford: How Worried Should You Be?
If it has not been started, worry far less than you likely are. "Have I wrecked it?" is the first question everyone in Stapleford asks, and the truthful answer is generally no, because petrol resting in a diesel tank harms nothing until it's drawn through the system — by ignition priming, by the starter, or by driving. To leave the car like that, ring Petrol in Diesel and leave the engine alone. The remainder of this page explains what petrol really does to a diesel, how to tell 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 the motor
Two jobs fall to diesel on its journey round a motor. Before it burns, it lubricates — and then it combusts. Your high-pressure pump and the fuel injectors are built to extremely fine clearances, and your diesel passing through them is what keeps those surfaces from wearing against one another.
Of those two tasks, petrol handles the first badly and the second never. The clattering comes from petrol being made not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the fuel system depends on, and any pump working on that mixture is wearing itself.
Together, those leave the shape of the problem plain. Not contact but circulation is what does the damage. A tank with petrol in it is a fuel problem. A pump that has been working on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the injectors downstream.
How serious is petrol in a diesel? Four scenarios we see in Stapleford
Fuelled but not once started — as good as it gets. Only your tank has petrol in it, and so the job is emptying your tank and purging your system where the vehicle stands. This situation can only truly take place on a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a moment. Your system has been bled, and so petrol has left that tank and reached your filter and your lines. That is normally still a simple job — a drain, a flush, and the fuel filter seen to.
Driven a few miles. Now your pump has spent these miles working on weakened fuel. Distance is only half of it; how hard it was driven matters just as much. Either way the work includes your tank, the fuel lines, the filter and clean fuel through the whole circuit. Short trips, like the school run to Stapleford Community Primary School, are one matter. A run as far as Cambridge, under 5 miles away, is a very different job. So is any mileage on the M11, under 3 miles from Stapleford, where the motor has been labouring hard throughout.
Driven on till it protested — knocking, smoke, a lumpy idle, a soft throttle. That is your engine telling you its fuel no longer is acting like diesel. Stop where you are — on the verge on Gog Magog Way, at the kerb, down a side road — and don't move it again. Long-term damage is very uncommon when a vehicle is pulled over quickly, and the drain and flush-through that still come first take care of it.
Petrol in a diesel myths Stapleford motorists hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mix. The assumption behind the guidance — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite holds. Myth: "A current diesel can cope with a bit of petrol." A modern diesel runs its fuel through finer components at higher pressure, which makes the protection count more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there is no harm done." The motorist of a petrol motor fed diesel usually stops, since it will not run, and the harm stops there. A diesel fed petrol normally starts, idles and drives away as though nothing has happened, while your pump wears. Being able to run is not proof of being fine.
An old fix for a separate issue lies behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has weakened remains weakened, and that petrol remains in that tank regardless.
The next start sends petrol back round your pump out of the fuel lines and the fuel filter, where some of that sits after the motor has run. That is why a DIY tank drain doesn't leave you sorted — a myth. Besides, petrol drained into a can by the road is truly hazardous.
How does petrol in a diesel occur?
It's rarely carelessness, and nobody does it on purpose. The forecourt makes it easy: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally will not go into a petrol vehicle at all. So the slip runs one way.
Habit and your car falling out of step is when it happens. Courtesy car, hire car, or a motor that is new. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. Filling up in a rush on the way to Shelford, with a train to catch. Years of petrol motors behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that is when. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
How to prevent petrol in a diesel at your next fill-up in Stapleford
- Green for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Go by the label on the pump, not the colour.
- In a motor you don't know, look inside the flap over the filler or at the cap before your first fill: many cars state the fuel there.
- Label your key. In a household with one of each, a coloured fob or a sticker on the 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 take the nozzle off the petrol pump. It seems silly and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck the phone away and keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to reject a petrol nozzle, and add-on devices are available for cars without one. They are a safety net, not a reason to stop reading the pump.
- As soon as you notice, stop: less petrol in the tank means a weaker blend. What to do next doesn't change, though — still do not crank it.
Stapleford: already put petrol in a diesel?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition off too. If you are still at the forecourt — Esso or anywhere else — ask the attendants to help you roll the vehicle away from the pump. Next, 0333 366 0103. We'll ask what was put in, roughly how much, and if it has been run.
If it was AdBlue rather than petrol, say so. That is a separate fault — corrosion and deposits instead of lost protection — and it has its own page for Stapleford.
Why one petrol in a diesel task in Stapleford costs more than another
The four situations above are four different jobs, so no single quote for this would be honest. Which of them you are in is mostly what shifts your cost. Where your car is matters too, and whether a van can safely reach it, after the share of petrol to what the tank holds.
Three queries come first, before any quote, instead of after — what went in, how much, has it run — and this is the reason. Those replies are what change a range into one firm number.
About Stapleford
Stapleford is a village in Cambridgeshire, situated on the River Granta, with a low elevation of around 23 metres. Stapleford lies near the city of Cambridge, approximately 4.2 miles to the southeast, and is close to nearby places such as Freestones Corner, Great Shelford, and Little Shelford. Stapleford has a population of around 1616 people, predominantly living in detached houses.
Stapleford and Cambridgeshire: where our fuel drain cover reaches
Stapleford waits in the CB postcode area, and the teams that answer petrol in diesel call-outs there work the locations near it as well — Freestones Corner, Great Shelford and Little Shelford among them. The vehicle doesn't need to come to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Stapleford and still at the pump?
The best spot there is, then — that's where you are. Keep it off. Phone.