Littlebourne: Petrol in a Diesel Car? How Worried to Be
Probably less than you already are — provided no one has started it. Till your ignition primes your pump, the starter cranks, or the car is driven, petrol in a diesel tank simply waits there and does nothing. Which makes the honest reply to the first Littlebourne question — "have I wrecked it?" — normally no. To keep the vehicle like that, ring Petrol in Diesel then leave your engine alone. The rest of this page sets out what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
Inside the engine: what petrol in a diesel does
On its way through a motor, diesel does two tasks. It lubricates first, and after that does it burn. Very fine gaps go into the injectors and the high-pressure fuel pump, and only the diesel running through keeps those surfaces from grinding together.
The second job petrol doesn't do at all, and the first it does badly. A pump running on a petrol mixture is wearing itself out, since petrol is thinner than diesel and strips out the lubrication your fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where the rattling starts.
Put those together and the shape of the trouble is clear. The damage is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel fault. Once the pump has been working on that petrol, a mechanical fault has begun: whatever is shed by a pump that's wearing down travels downstream to your injectors with your fuel.
Petrol in a diesel in Littlebourne: how serious is it? Four situations
Filled up, and not started: no case is better. On a forecourt, and genuinely only there, the petrol is still limited to that tank — since anywhere else your car was driven to get to it. The job is draining and rinsing on the spot.
Your ignition turned on, or a brief start. Once primed, the system has pulled petrol out of your tank as far as the fuel filter and the lines. Still generally simple: drain, flush, and the fuel filter sorted.
Those few miles on the road meant your pump labouring on fuel diluted by petrol throughout. The work is that tank, your lines, your filter and fresh fuel through the whole circuit, and how hard the car was driven counts as much as how far. On the school run to Littlebourne Church of England Primary School, the mileage is small. A run as far as Canterbury, under 5 miles away, is a very different task. So is any mileage on the M2, under 15 miles from Littlebourne, where the engine has been running hard throughout.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven till it complained. The fuel isn't behaving like diesel any more, and the engine is saying so. Whether it's the verge on Orchard Close, a lay-by or a side street, stop there and leave it. Permanent damage is very rare if a vehicle is stopped soon, and the drain and flush-through that still come first sort it out.
Littlebourne people and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. A bigger tank of the same mixture is all it gives, since topping up removes nothing. The assumption behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. Finer parts and higher pressure are the way a current diesel runs its fuel, and that makes the lubrication count more, not less.
This is the one that catches drivers. Myth: "If it starts and drives, there is no harm done." Any petrol engine fed diesel normally will not run, and so the motorist stops and the damage stops with them. Feed petrol to a diesel and it usually fires up, idles and drives away like nothing happened — all the while its pump wears. Being able to run is not proof of being fine.
Not so: a two-stroke additive makes it safe to drive home. It was an old workaround, meant for another issue. What petrol has diluted remains diluted, and that petrol remains inside your tank regardless.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol sits in your filter and lines, ready to go straight back through the pump on your next start. Emptying petrol into a can at the roadside is also really risky.
How it happens: petrol in a diesel
It's rarely carelessness, and no one does it on purpose. The forecourt makes it easy: the petrol nozzle is the slimmer of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol car at all. So the slip runs one way.
The moment habit stops matching your car is the moment it happens. A vehicle that is new to you — hired, on loan as a courtesy car, or brand new. One petrol and one diesel on the drive of the same household. The pumps in a different order on a well-known forecourt. Rushing for a train outside Bekesbourne and filling up en route. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it has always done.
Littlebourne 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 each forecourt. Trust the label on the pump, not the colour.
- The first fill in an unfamiliar car is the time to check the filler flap — on it, or on the cap, many cars state the fuel they take.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, for a house with one of each.
- Before the nozzle comes off the petrol pump the first time you fill a hired or new vehicle, say "diesel" aloud. Daft, yes, yet it works.
- While you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to block a petrol nozzle, and add-on devices exist for vehicles without one. They are a backstop, not a reason to stop checking the petrol pump.
- Noticing it halfway? Stop at once. A weaker mixture results from less petrol inside the tank, yet your next step remains the same: don't fire it up.
Petrol already in a diesel around Littlebourne? Begin here
Short and simple, then, is the order of things. Never start the car, and don't turn your ignition on. If you're still on the forecourt — Shell or anywhere else — ask the attendants to help you roll it away from the petrol pump. Phone 0333 366 0103 next, with three facts — your fuel, the rough volume, and whether it has run.
Say so if it was AdBlue rather than petrol: it's a separate problem, with its own page for Littlebourne, because AdBlue brings corrosion and deposits instead of lost protection.
One petrol in a diesel job in Littlebourne costs more than another. Why?
A fair single quote doesn't exist here: four scenarios, four separate jobs. The situation itself does most of the work of moving the cost. Two things come after that: the petrol that was put in as a proportion of what the tank takes, then the spot your car is in and whether our van can get to it safely.
What went in, how much, and if it's run — three questions we ask before quoting, not after, for precisely that reason. Their replies are what turn a range into one firm number.
About Littlebourne
Littlebourne is a village situated on the banks of the River Stour in Kent, with a low elevation of around 14 metres above sea level. Littlebourne lies close to the city of Canterbury, approximately 3.7 miles away, and is surrounded by nearby villages such as Ickham and Wickhambreaux. Littlebourne has a mix of housing types, but semi-detached homes are the most predominant. Littlebourne is located within the South East region of England, about 58 miles from London.
Littlebourne and Kent: where our fuel drain cover runs
Petrol in diesel calls around Littlebourne — part of the CT postcode area — go to teams that also cover the locations round it, Ickham, Bramling and Wickhambreaux included. You need not bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots we drain.
In Littlebourne and still at the petrol pump?
Then you're in the best position there is. Switched off it remains; then phone.