Great Cornard: Petrol in a Diesel Car? How Worried to Be
Probably less than you already are — provided no one has started the vehicle. Till your ignition primes the pump, the starter turns, or the car is driven, petrol in a diesel tank simply sits there and does no harm. Which means the truthful reply to that first Great Cornard question — "have I wrecked it?" — usually no. Leave the motor off then phone Petrol in Diesel — that is how you keep it like that. Below, this page sets out what petrol really does inside a diesel, how far it may have gone, and how to stop it happening to you a second time.
Inside your engine: what petrol in a diesel really does
Passing through a motor, diesel is doing two jobs at once. Lubricating comes before burning; it does both. What keeps the surfaces inside your high-pressure pump and the injectors from wearing against each other is the diesel flowing through them — they're built to very fine tolerances.
Petrol handles the first task badly and the second not at all. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection the system rests on, and any pump running on such a mix is wearing itself.
Combined, those make the shape of the problem clear. It's movement that does the damage, not contact. All a tank with petrol in it amounts to is a fuel fault. After the pump has been running on that petrol, a mechanical problem has begun: whatever is shed by a pump that's grinding is carried downstream to the injectors with your fuel.
Great Cornard, petrol in a diesel: four situations, from mild to serious
The best case there is: filled up, not once started. Only that tank has petrol in it, and so the task is clearing your tank and flushing the system where the car sits. This scenario can only truly occur at a forecourt: anywhere else, the car got there by being driven.
A moment's running, or merely the ignition on. With the fuel system primed, the lines and filter now hold petrol that came from the tank. Drain, flush, see to the fuel filter: still normally straightforward.
Driven a few miles. Now your pump has spent these miles running on thinned fuel. How hard the vehicle was driven counts as much as how far, and this work covers the tank, the fuel lines, the fuel filter and clean fuel through the whole system. On the school run to Wells Hall Primary School, the distance is small. Any mileage on the M11, under 25 miles from Great Cornard, means the motor has worked hard throughout, and a run to Colchester, under 15 miles away, makes a very different job too.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. That is your engine telling you its fuel no longer is acting like diesel. Leave it where it stops: a lay-by, a side street, the verge on Nursery Road. What comes first is still the drain and flush-through, and that takes care of it, with long-term damage very rare when a vehicle is pulled over soon.
Stories Great Cornard drivers hear about petrol in a diesel
False: topping up to full with diesel makes it fine. It does not. Topping up takes out nothing; it gives you a fuller tank of the same mix. A diesel fuel system doesn't accept petrol by percentage in the way that advice supposes.
Myth: a current diesel copes with a bit of petrol. If anything, the reverse. More precise components and higher pressure are the way a newer diesel runs its fuel, and that makes the lubrication count more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools people. A petrol engine fed diesel usually will not run, and so the driver stops and the damage stops with them. A diesel fed petrol generally starts, idles and drives away as if nothing has happened, whilst your pump grinds. Fine and running aren't the same at all.
Myth: a two-stroke additive lets you to drive home. It was an old fix, supposed for another fault. It does not put back what petrol has weakened, and that petrol is still inside that tank later on.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol sits in the fuel filter and lines, ready to go straight back through the pump on your next start. It's also truly hazardous to drain petrol into a can by the roadside.
Why petrol in a diesel happens so easily
A careless moment is seldom the cause, and nobody means to do it. The forecourt makes it simple: the petrol nozzle is the slimmer 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 vehicle at all. So the slip runs one way.
It occurs when habit and the vehicle stop matching. Any vehicle that is new to you — hired, 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. Filling up in a hurry on the way to Sudbury Suffolk, with a train to catch. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. With rain, a call coming in, or a car full of children to deal with, the hand simply does what it always has.
Avoiding petrol in a diesel next time you fill up around Great Cornard
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on every forecourt. The label is what matters.
- The first fill in a strange car is the time to check the filler flap — inside it, or on the cap, many vehicles state the fuel to use.
- A coloured fob or a sticker on the 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 your first fill in a new or hired car, say "diesel" out loud before you lift 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.
- Add-on devices exist for motors without one, and some diesels come with a filler that will not take a petrol nozzle. Helpful — but a backstop only, never a reason to stop checking the label.
- Noticing it halfway? Stop at once. A weaker mix follows from less petrol inside the tank, yet the next step remains the same: do not start the vehicle.
Great Cornard: already put petrol in a diesel?
Then the order of things is short. Leave it unstarted, with the ignition off too. Ask the staff to help you push it clear of the pump if you are still on the forecourt, whether that is Sainsbury's or somewhere else. Call 0333 366 0103 next, with three facts — the fuel, the approximate volume, and whether it's run.
Corrosion and deposits form the trouble with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and see its own Great Cornard page.
One petrol in a diesel job in Great Cornard costs more than another. Why?
Four separate jobs lie behind the four situations above — which is why there's no fair single price. Chiefly, your cost moves with which situation you're in. Where the vehicle is counts too, and whether a van can safely get to it, after the proportion of petrol to what your tank holds.
What was put in, how much, and whether it has run — three queries our engineers ask before pricing, not after, for precisely that reason. Given those replies, you get a straight figure instead of a range.
About Great Cornard, briefly
Great Cornard is a suburban area in Suffolk, situated on the River Stour at an elevation of 27 metres. Great Cornard lies near the market town of Sudbury and the village of Little Cornard, with the city of Colchester approximately 11 miles to the south. Great Cornard has a mix of housing types, but semi-detached homes are particularly prevalent in the area. Great Cornard is also close to other nearby places, including Henny Street and Cornard Tye, and is around 52 miles from London.
Fuel drain cover in Great Cornard and across Suffolk
Little Cornard, Henny Street and Cornard Tye are among the spots near Great Cornard that the same teams work, answering petrol in diesel call-outs across Great Cornard's CO postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations our engineers work, and the vehicle doesn't need to come to us.
In Great Cornard and still at the pump?
The best place there is, then — that is where you are. Leave it switched off, and ring.