Coupe Green: Petrol in a Diesel Car? How Worried to Be
If it hasn't been started, you can worry far less than you probably are. "Have I ruined it?" is the first question anyone in Coupe Green asks, and the honest answer is generally no, because petrol resting in a diesel tank hurts nothing till it is drawn through the system — by ignition priming, by your starter, or by being driven. To keep it like that, call Petrol in Diesel and leave your engine switched off. What petrol really does to a diesel, how to gauge how far it's travelled, and how to stop it from happening again: that's the rest of this page.
What petrol in a diesel does to the motor
Passing through an engine, diesel is doing two things at once. It burns, and before it burns it protects. What keeps the surfaces inside the high-pressure pump and your injectors from wearing against one another is the diesel passing through them — they are made to very fine gaps.
The second job petrol does not do at all, and the first it does badly. A pump running on a petrol mix is wearing itself out, because petrol is runnier than diesel and takes away the protection the fuel system relies on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that is where any rattling comes.
Taken together, they make clear what shape the trouble has. It is circulation that does the damage, not contact. Where the petrol is only inside the tank, it is a problem of fuel, nothing more. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to the injectors downstream.
Petrol in a diesel around Coupe Green: how serious is it? Four situations
Fuelled but not once started — the best it gets. At a forecourt, and genuinely only there, that petrol is still limited to that tank — since anywhere else the car was driven to reach it. The task is emptying and rinsing on the spot.
Ignition on, or started for a moment. Your system has been primed, so petrol has left the tank and got to the filter and the fuel lines. Still normally simple: drain, flush, and your filter dealt with.
Your pump has spent a few miles on weakened fuel — that's what driving the vehicle does. Tank, lines, filter, then clean fuel put through the entire system: that is this work, and the way the car was driven matters as much as the miles. Short trips, such as the school run to Coupe Green Primary School, are one thing. A run as far as Preston, under 5 miles away, is a very different job. So is any distance on the M61, under 3 miles from Coupe Green, where your engine has been running hard throughout.
Driven until it protested. Knocking, a lumpy idle, smoke, a throttle that has gone soft. The fuel isn't behaving like diesel any more, and your engine is saying so. Whether it's the verge on Daub Hall Lane, a lay-by or a side road, stop there then leave it. Lasting damage is very uncommon if a vehicle is pulled over early, and the fuel drain and flush-through that still go first sort it out.
Myths Coupe Green motorists hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. That advice assumes a diesel fuel system handles petrol by percentage. It does not.
"Newer diesels can handle a little petrol" — a myth, and nearer the opposite. A newer diesel runs its fuel through smaller parts at higher pressure, which makes the lubrication count more, not less.
One myth that catches people out: if it starts and drives, it must be unharmed. Any petrol engine fed diesel usually will not run, so the motorist stops and the harm stops with them. Feed petrol to a diesel and it normally fires up, idles and drives away like nothing happened — all the while its pump wears. Running doesn't mean fine.
Myth: a two-stroke additive makes it safe to drive home. It is an old workaround, supposed for another problem. None of what petrol thinned gets put back by it — and afterwards, the tank still holds the petrol.
If the motor has run, part of the petrol is in your filter and your lines, not your tank — and your next start pulls it straight back through the pump. So the myth "drain your tank yourself and you are sorted" doesn't hold. Also, a can of petrol drained by the roadside is truly dangerous.
How does petrol in a diesel happen?
It's seldom carelessness, and nobody does it on purpose. One way only, because of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally will not fit a petrol car. That's how the forecourt makes it easy.
Habit and the car falling out of step is when it occurs. A new vehicle, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. A forecourt you know, but with its pumps arranged differently. A train to catch, and a hurried fill on the way to Bamber Bridge. A new-to-you diesel Volkswagen Tiguan, its first fuelling, and a driver accustomed to petrol: precisely when it occurs. Add rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Next time you fill up around Coupe Green: avoiding petrol in a diesel
- Green for unleaded and black for diesel is normal in the UK — but not on every forecourt. Trust the label on the pump, not the colour.
- In a car 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.
- A coloured fob or a sticker on the diesel's key does 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 fuel a hired or new car, say "diesel" aloud. Daft, perhaps, but it works.
- Mistakes like this are simple to make whilst your mind is on something else, so your phone goes away.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the petrol pump.
- As soon as you notice, stop: less petrol inside that tank means a thinner mixture. What to do next does not change, though — still don't start the vehicle.
Put petrol in a diesel in Coupe Green already?
Short and simple, then, is the order of things. Do not start the vehicle, and do not turn your ignition on. The attendants on the forecourt — whether at Texaco itself or wherever you filled up — will normally help push it away from the petrol pump if you ask. Next, 0333 366 0103. We'll ask what was put in, about how much, and if it has been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate problem — Coupe Green has a page all for it.
What makes one Coupe Green petrol in a diesel job cost more than the next
There's no fair single quote for this, because the four scenarios above are four separate jobs. What shifts your cost is chiefly which of them you are in. Where the vehicle is counts too, and whether our van can safely get to it, after the proportion of petrol to what the tank holds.
Three queries come first, before quoting, instead of after — what went in, how much, has it run — and that is the reason. Their answers are what turn a range into one firm number.
About Coupe Green and its setting
Coupe Green is a village in Lancashire, situated on the riverside at an elevation of 45 metres, with detached housing being the predominant type of accommodation. Coupe Green lies close to the city of Preston, approximately 3.4 miles away, and is near other local places such as Coup Green, Gregson Lane, and Higher Walton. Coupe Green has a population of around 850 residents and is located in the North West region of England, about 186.4 miles from London.
Across Lancashire and in Coupe Green: fuel drain cover
Coupe Green waits in the PR postcode area, and our vans that answer petrol in diesel calls there work the locations near it as well — Coup Green, Gregson Lane and Higher Walton among them. A forecourt, a supermarket car park, a lay-by or your own drive are all locations we drain, and the vehicle does not need to move to us.
At the petrol pump around Coupe Green, right now?
In that case, you couldn't be in a better spot. Switched off it remains; then phone.