Alwalton: Petrol in a Diesel Car? How Worried to Be
If it has not been started, you can worry far less than you probably are. Petrol resting in a diesel tank does nothing to the motor until something draws it through the fuel system — the ignition priming your pump, your starter, or the drive on its own. So the truthful answer to the first question anyone around Alwalton asks, "have I wrecked it?", is normally no. Keep it that way: leave the engine off and call Petrol in Diesel. What petrol really does to a diesel, how to judge how far it's travelled, and how to stop it from happening again: that's the remainder of this page.
What petrol in a diesel does to the motor
Passing through an engine, diesel does two things at once. It ignites, and before it combusts it lubricates. The high-pressure pump and the fuel injectors are built to very fine clearances, and the diesel passing through them is what stops those surfaces from grinding against one another.
Petrol handles the first task badly and the second not at all. The rattling 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 runnier than diesel, it strips away the protection your system depends on, and any pump running on such a mixture is wearing itself.
Taken together, they make clear what shape the trouble takes. Contact does not do the harm — movement does. All a tank with petrol in it amounts to is a fuel fault. The beginning of a mechanical one is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Four scenarios our engineers see in Alwalton: how serious is petrol in a diesel?
Filled but not once started — as good as it gets. That petrol is in the tank and only the tank, and the job is a drain and a flush where the car sits. This is the one situation that can only truly take place on a forecourt, since anywhere else the vehicle has been driven to get there.
Started for a second, or only the ignition on. With the fuel system primed, your lines and filter now contain petrol that came from your tank. Drain, flush, see to your filter: still usually easy.
A few miles driven, and the pump has spent every one of them labouring on weakened fuel. The work is that tank, the lines, your filter and clean fuel through the entire system, and how hard the vehicle was driven matters as much as how far. Short trips, like the school run to Orton Wistow Primary School, are one thing. A run as far as Peterborough, under 5 miles away, is a very different job. So is any mileage on the Great North Road, under a mile from Alwalton, where your engine has been working hard the whole time.
Driven on till it protested — clattering, smoke, a lumpy idle, a dead throttle. What you are hearing is the motor reporting fuel that no longer behaves like diesel. Stop where you are — on the verge on Allerton Garth, at the kerb, down a side road — and don't move it again. A car stopped early very seldom has lasting damage, since the fuel drain and the flush-through, which still go first, take care of it.
Myths Alwalton motorists hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing comes out when you top up — that tank just holds more of the same blend. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance assumes.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. Lubrication matters more on current diesels, not less, because their fuel passes through finer parts at higher pressure.
This is the one that fools people. Myth: "If it starts and drives, there is no harm done." The motorist of a petrol motor fed diesel usually has no choice but to stop, because it will not run, and the damage stops with them. While the pump grinds, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. Being able to run is not the same as being fine.
Myth: "Add some two-stroke oil and drive the car home." It is an old workaround for a distinct problem. It doesn't put back what petrol has thinned, and that petrol is still inside the tank afterwards.
Myth: "Drain that tank yourself and you are sorted." After your engine has run, some of that petrol is no longer inside your tank: it is in your filter and the lines, and it goes right back through your pump on the next start. It's also really hazardous to drain petrol into a can by the kerbside.
How does petrol in a diesel take place?
No one does it on purpose, and it is seldom carelessness. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle generally won't go into a petrol vehicle at all. So the error runs one way.
It takes place when routine and your car stop matching. A new vehicle, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. A familiar forecourt with the pumps in a different order. A train to catch, and a rushed fill en route to Peterborough. Precisely the moment it occurs: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. Throw in rain, a phone call or a back seat full of children, and your hand repeats what it has always done.
How to prevent petrol in a diesel on your next fill-up around Alwalton
- A green handle 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.
- Plenty of motors state the fuel type inside the filler flap or on the cap, and so check there on the first fill in a car you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of intending to remember, for a home with one of each.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car needs its first tank. It sounds silly. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away and keep your mind on the pump.
- Some diesels have a filler designed to refuse a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the pump.
- Stop the moment you realise. Less petrol inside the tank makes a thinner mixture. It doesn't change what to do next, which is still not to start the vehicle.
Already put petrol in a diesel around Alwalton?
The order of things is brief, then. Leave it unstarted, with your ignition off as well. Ask the staff to help you roll it clear of the petrol pump if you are still on the forecourt, whether that's Welcome Break or somewhere else. Phone 0333 366 0103 next, with three answers — the fuel, the approximate volume, and whether it has run.
Say so if it was AdBlue instead of petrol: it's a separate problem, with its own page for Alwalton, since AdBlue brings corrosion and deposits instead of lost lubrication.
What makes one Alwalton petrol in a diesel task cost more than the next
Four separate tasks sit behind the four situations above — which is why there's no fair single price. The scenario itself does most of the work of moving the cost. Where the vehicle is counts too, and whether a van can safely get to it, after the share of petrol to what that tank takes.
Before any quote, not after, come three queries: your fuel that went in, the quantity, and if it's run. That is why. A range becomes a straight figure when those answers are in.
About Alwalton, for a moment
Alwalton is a small suburban area situated on the banks of the River Nene in Cambridgeshire, with a mix of detached housing and open spaces. Alwalton lies close to the city of Peterborough, approximately 4 miles to the west, and is part of the wider Peterborough urban area. Alwalton's riverside setting and low elevation of around 26 metres give it a distinctive character, with nearby places like Orton Northgate and Lynch Wood also forming part of the local landscape.
Fuel drain cover across Cambridgeshire, Alwalton included
The vans answering petrol in diesel calls around Alwalton, in the PE postcode area, equally work the places around it, Orton Northgate, Lynch Wood and Chesterton included. Our engineers drain where the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the pump in Alwalton, right now?
Then you are in the best place there can be. Turned off it remains; then ring.