Petrol in a Diesel Car in Cornwood: How Worried Should You Be?
Provided it hasn't been started, worry far less than you probably are. Everyone around Cornwood begins with "have I wrecked it?", and the honest answer is normally no: petrol resting inside the tank of any diesel remains harmless till priming, cranking or driving pulls it into the fuel system. Leave the engine off and call Petrol in Diesel — that is how you keep it like that. Below, this page sets out what petrol actually does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Inside your engine: what petrol in a diesel does
Passing through an engine, diesel does two jobs at once. Before it ignites, it lubricates — then it ignites. Very fine gaps go into the injectors and the high-pressure pump, and just the diesel running through stops their surfaces grinding together.
Petrol handles the first job poorly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump running on that mixture to wear itself. It is also made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the rattling.
Together, those leave the shape of the trouble plain. Contact doesn't do the damage — movement does. A tank with petrol in it is a fuel problem. The start of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds moves on with the fuel to the fuel injectors downstream.
Petrol in a diesel in Cornwood: how bad is it? Four cases
Fuelled but not once started — the best it gets. That petrol is in that tank and only the tank, and the job is a drain and a flush where the vehicle stands. This is the one scenario that can only truly take place at a forecourt, because anywhere else your car has been driven to get there.
Ignition on, or started for a second. Your system has been primed, so petrol has left your tank and reached your filter and your lines. Still normally straightforward: drain, flush, and the fuel filter dealt with.
Those few miles driven meant your pump working on fuel thinned by petrol throughout. How hard the vehicle was driven counts as much as how far, and the work takes in that tank, the lines, the filter and clean fuel through the entire circuit. Driving the kids to Cornwood Church of England Primary School is one sort of trip. A run as far as Plymouth, under 10 miles away, is a very different task. So is any mileage on the M5, under 50 miles from Cornwood, where your engine has been running hard the whole time.
Driven on until it complained — rattling, smoke, a lumpy idle, a dead throttle. The fuel isn't behaving like diesel any more, and your engine is telling you. Whether it's the verge on Newtown, a lay-by or a side road, stop where you are and leave it. What comes first is still the drain and flush-through, and that takes care of it, with permanent damage very rare when a vehicle is stopped early.
Cornwood drivers and the petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed by topping up — you're left with a bigger tank, still the same mix. Percentage is not how a diesel fuel system copes with petrol, however much that guidance assumes.
Not so: a current diesel copes with a bit of petrol. Rather, the opposite. Lubrication matters more on current diesels, not less, since their fuel passes through finer parts at higher pressure.
"It starts, it drives, so there is no harm" — the myth that trips up more people than any other. Any petrol motor fed diesel usually will not run, and so the motorist stops and the damage stops with them. While the pump wears, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the car home." It is an old fix for a separate fault. It does not put back what petrol has thinned, and the petrol is still inside your tank later.
Myth: "Drain your tank yourself and you are sorted." Once your engine has run, some of the petrol is no longer in your tank: it is in your filter and the fuel lines, and it goes straight back through your pump on your next start. And, a can of petrol filled at the kerbside is truly hazardous.
Petrol in a diesel: how does it occur?
Nobody does it on purpose, and it is seldom carelessness. 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, while a diesel nozzle mostly won't go into a petrol car at all. So the slip runs one way.
The moment habit stops matching the vehicle is the moment it happens. A vehicle that is new to you — a hire car, on loan as a courtesy car, or just bought. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps arranged differently. A train to catch, and a hurried fill on the way to Ivybridge. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Tiguan for the first time. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
Avoiding petrol in a diesel next time you fill up around Cornwood
- The label is what counts, and so check the petrol pump instead of the colour: in the UK unleaded handles are normally green and diesel black, yet not on every forecourt.
- The first fill in a new vehicle is the time to check the filler flap — inside it, or on the cap, many cars state the fuel they take.
- Label the key. In a house with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It sounds daft and it works.
- Tuck your phone away. This is an easy mistake to make while you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop checking the petrol pump.
- Stop the moment you realise. Less petrol inside the tank means a weaker blend. It doesn't change what to do next, which is still not to crank it.
Already put petrol in a diesel in Cornwood?
The order of things is brief, then. Starting it is out, and so is turning on your ignition. Ask the staff to help you push it away from the pump if you're still at the forecourt, whether that's Tesco or somewhere else. Call 0333 366 0103 next, with three answers — your fuel, the approximate amount, and if it has run.
Corrosion and deposits are the problem with AdBlue, where petrol brings lost protection. So if it was AdBlue, say so — and read its own Cornwood page.
Why one petrol in a diesel task in Cornwood costs more than another
There's no fair single quote for this, since the four situations above are four different tasks. Mostly, your cost moves with which one you're in. Two things come after that: the petrol that got in as a proportion of what that tank holds, then the place the vehicle is in and whether a van can get to it safely.
Three questions come first, before any quote, rather than after — what got in, how much, has it run — and this is the reason. The replies change a range into a straight figure.
About Cornwood
Cornwood is a village situated on the River Yealm in Devon, with a mix of rural and riverside landscapes at an elevation of around 127 metres. Cornwood lies approximately 8.5 miles from Plymouth and is surrounded by nearby places such as Corntown, Lutton, and Yondertown. Cornwood has a population of around 555 people and is characterised by predominantly detached housing.
Cornwood and Devon: where our fuel drain cover runs
The teams answering petrol in diesel jobs around Cornwood, in the PL postcode area, equally work the locations near it, Corntown, Lutton and Yondertown included. You need not move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
In Cornwood and still at the pump?
Nothing beats it: that is where you are. Call, and keep it switched off.