How Worried Should You Be? Petrol in a Diesel Car in Larkfield
Not started? Then less anxious than you probably are. Everyone in Larkfield starts with "have I ruined it?", and the fair answer is normally no: petrol resting inside that tank of a diesel remains harmless till priming, cranking or driving pulls it into the fuel system. Keep it that way: leave the engine off and ring Petrol in Diesel. Further down, you will find what petrol actually does inside a diesel, how far it may have got, and how to stop it happening to you a second time.
What petrol in a diesel does to the motor
On its way through an engine, diesel does two jobs. Oiling comes before burning; it does both. The high-pressure fuel pump and the injectors are made to very fine tolerances, and the diesel passing through them is what stops those surfaces from wearing against each other.
Badly at the first, not at all at the second: that is petrol. The clattering 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 out the lubrication the system hinges on, and any pump running on that mix is wearing itself.
The shape of the problem is plain once you put those together. The harm is done by movement, not by contact. Any tank with petrol in it is a fuel issue. Whatever a worn pump sheds goes on, borne by the fuel, into your injectors downstream, which is why a pump that has worked on that petrol is where a mechanical fault begins.
How serious is petrol in a diesel? Four situations our technicians see around Larkfield
The best case there is: filled up, never started. That petrol is in the tank and just that tank, and the job is a drain and a flush where your car sits. This is the one scenario that can only really take place on a forecourt, since anywhere else the car has been driven to get there.
Ignition on, or started for a moment. The system has been primed, so petrol has left that tank and reached your filter and the lines. Usually nothing more than clearing, cleaning and seeing to your filter, and so still straightforward.
A few miles driven, and your pump has spent every one of them running on thinned fuel. Tank, lines, filter, then fresh fuel put through the entire system: that's this work, and the way the vehicle was driven matters as much as the mileage. Driving the kids to Brookfield Junior School is one sort of trip. Very different again: a run to Southend-on-Sea, under 25 miles away, or any distance on the M20, under a mile from Larkfield, where your engine never stopped working hard.
Driven on till it complained — rattling, smoke, a ragged idle, a dead throttle. The engine is telling you your fuel is no longer acting like diesel. Stop on the spot — on the verge on Kingfisher Road, at the kerb, down a side road — and don't move it. Lasting damage is very unusual if a car is stopped quickly, and the fuel drain and flush that still go first take care of it.
Larkfield motorists and that petrol in a diesel myths they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing is removed by topping up — you're left with a fuller tank, still the same mix. The idea behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the reverse is true. Myth: "A modern diesel can cope with a bit of petrol." Smaller 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 damage done." This is the one that catches people. Feed diesel to a petrol engine and it generally won't run, and so the motorist stops — and the harm stops with them. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, while the pump grinds. Fine and running aren't the same thing.
An outdated workaround for a separate fault is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol weakened is put back by it — and afterwards, the tank still holds that petrol.
Once your engine has run, part of the petrol sits in your filter and the lines, not your tank — and your next start pulls it straight back through the pump. So the myth "drain that tank yourself and you are sorted" does not stand up. Besides, petrol cleared into a can by the road is truly risky.
Why petrol in a diesel occurs so easily
A careless moment is rarely the cause, and nobody means to do it. The forecourt makes it easy: the petrol nozzle is the slimmer of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle mostly won't go into a petrol motor at all. So the slip runs one way.
It happens when habit and your car stop matching. Courtesy car, hire car, or a motor that is brand new. A household with one petrol and one diesel on the drive. A well-known forecourt with the pumps in a different order. A train to catch, and a hurried fill en route to New Hythe. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver accustomed to petrol: exactly when it occurs. With rain, a call arriving, or a car full of children to deal with, the hand simply does what it always has.
Preventing petrol in a diesel next time you fill up in Larkfield
- A green handle 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.
- Many vehicles state the fuel type inside your filler flap or on the cap, and so check there on your first fill in any car you do not know.
- One of each in the household? Mark the key to your diesel — a bright fob, a sticker — because meaning to remember isn't enough.
- Before the nozzle leaves the pump the first time you fill a hired or new car, say "diesel" aloud. Daft, perhaps, yet it works.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away then keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices are available for cars without one. They are a safety net, not a reason to stop checking the petrol pump.
- The moment you notice, stop: less petrol inside the tank makes a thinner blend. What to do next does not change, though — still do not start the car.
Already put petrol in a diesel around Larkfield?
Then the order of things is brief. Don't turn your ignition on, and don't fire it up. Yet at the forecourt, at Esso or anywhere else? Ask the staff to help you push the vehicle away from the petrol pump. Then call 0333 366 0103 and tell us what was put in, roughly how much, and if it has run.
Say so if it was AdBlue instead of petrol: it is a separate problem, with its own page for Larkfield, because AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel job around Larkfield costs more than another. Why?
There is no fair single price for this, because the four situations above are four different jobs. Chiefly, your cost shifts with which situation you are in. Beyond that it is the ratio — how much petrol was put in against how much that tank takes — and after that where the car is and whether our van can reach it safely.
That is why our engineers ask three queries before costing rather than after: what went in, how much, and whether it has run. A range becomes a straight figure when those answers are in.
About Larkfield and its setting
Larkfield is a village situated on the riverside in Kent, with an elevation of around 29 metres. Larkfield lies near the towns of Ditton, Lunsford, and New Hythe, and is approximately 20 miles from Southend-on-Sea. Larkfield has a population of around 2698 people, predominantly living in semi-detached housing. Larkfield is also within commuting distance of London, being around 28 miles from the city.
Across Kent and around Larkfield: fuel drain cover
Larkfield rests in the ME postcode area, and the teams that answer petrol in diesel calls there work the places around it as well — Ditton, Lunsford and New Hythe among them. No need to bring your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots we drain.
Larkfield: still at the petrol pump?
The best place there is, then — that is where you are. Leave the vehicle switched off, then ring.