How Worried Should You Be? Petrol in a Diesel Car in Hathersage
Probably less than you already are — provided nobody has started the vehicle. Everyone around Hathersage starts with "have I wrecked it?", and the honest answer is normally no: petrol resting inside that tank of any diesel stays harmless until priming, cranking or driving draws it into your fuel system. Leave your motor off then call Petrol in Diesel — that keeps it like that. The remainder of this page covers what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
What petrol in a diesel does to the motor
Diesel does two jobs on its way through a motor. It combusts, and before it combusts it lubricates. Designed to very fine gaps, the fuel injectors and your pump rely on the diesel flowing through them to keep their surfaces from wearing against one another.
Petrol does the first job poorly and the second not at all. A pump running on a petrol mixture is wearing itself out, because petrol is runnier than diesel and strips out the lubrication the fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where the knocking comes.
Put those together and the shape of the problem is clear. It is movement that causes the damage, not contact. All a tank with petrol in it amounts to is a fuel issue. The beginning of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to the injectors downstream.
Four situations our engineers see around Hathersage: how bad is petrol in a diesel?
The best case there is: filled up, not once started. Being on a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol held in that tank alone, it's cleared and flushed right where it stands, and nothing more is needed.
Ignition on, or started for a moment. Once primed, the fuel system has drawn petrol from your tank up to your filter and the lines. Drain, flush, see to the fuel filter: still normally straightforward.
Your pump has spent a couple of miles on weakened fuel — that is what driving the car does. How hard the car was driven matters as much as how far, and this work covers your tank, the fuel lines, your filter and fresh fuel through the entire system. On the school run to Hathersage St Michael's CofE (Aided) Primary School, the miles is short. Getting as far as Sheffield, under 10 miles away, makes a very different job — as does any miles on the M1, under 15 miles from Hathersage, with the engine working hard all the way.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven until it complained. The fuel is not behaving like diesel any more, and the motor is saying so. Leave it wherever it stops: a lay-by, a quiet street, the verge on The Crofts. What comes first is still the drain and flush-through, and that sorts it out, with lasting damage very uncommon if a vehicle is pulled over soon.
What Hathersage people get told about petrol in a diesel — and the myths in it
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. A bigger tank of the same mixture is all you get, because topping up takes out nothing. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance presumes.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the reverse. A modern diesel runs its fuel through smaller components at higher pressure, which makes the protection matter more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up more drivers than any other. Any petrol engine fed diesel normally will not run, so the motorist stops and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump wears. Fine and running aren't the same thing.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different issue. That petrol is still inside your tank afterwards, and whatever it has thinned is not put back.
The next start sends petrol back round the pump out of your lines and your filter, where some of it ends up after the engine has been run. That is why a DIY tank drain doesn't leave you sorted — a myth. It is also really hazardous to drain petrol into a can by the roadside.
How does petrol in a diesel happen?
Carelessness is seldom the cause, and no one means to do it. The forecourt makes it easy: 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 will not go into a petrol car at all. So the error runs one way.
The moment routine stops matching the vehicle is the moment it happens. Courtesy car, hire car, or a motor that is brand new. Two motors on one driveway, one petrol, one diesel. A forecourt you know, but with its pumps laid out differently. Fuelling up in a hurry en route to the nearest station, with a train to catch. The first fill-up in a diesel Volkswagen Tiguan after years of driving petrol is exactly the moment it happens. Add 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 at your next fill-up around Hathersage
- The label is what counts, so read the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on every forecourt.
- Plenty of vehicles state the fuel inside your filler flap or on the cap, so check there on the first fill in a vehicle you do not know.
- Good intentions count for less than a sticker or a fob in a vivid colour on your diesel's key if a house has one of each. So label it.
- Before the nozzle comes off the pump the first time you fill a hired or new motor, say "diesel" out loud. Silly, yes, but it works.
- Tuck the phone away. This is an easy mistake to make whilst you are thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to block a petrol nozzle, and aftermarket devices are available for the rest. Treat it as a backstop, then keep reading the pump.
- Less petrol makes a thinner blend, so stop as soon as you notice — though remembering that the next step is unchanged. It's still not to crank it.
Put petrol in a diesel in Hathersage already?
The order of things is brief, then. Don't start the car, and don't switch the ignition on. If you are still on the forecourt — Texaco or anywhere else — ask the staff to help you roll it away from the petrol pump. Next, 0333 366 0103. We will ask what got in, about how much, and if it has been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a separate fault — Hathersage has a page all for it.
One petrol in a diesel job in Hathersage costs more than another. Why?
The four situations above are four different jobs, so no single price for this would be fair. The scenario itself does most of the work of moving your cost. The share matters next, meaning how much of the tank is petrol, followed by the position of your car and whether reaching it is safe for a technician.
That is why we ask three queries before costing instead of after: what went in, how much, and if it has run. A range becomes a straight figure once those replies are in.
About Hathersage and where it is
Hathersage is a village situated in the Derbyshire countryside, beside the River Derwent, with a mix of semi-detached housing and other residential properties. Hathersage sits at an elevation of around 156 metres, near the edge of the Peak District National Park, and is close to nearby places such as Leadmill and Offerton. Hathersage is located approximately 8.5 miles from Sheffield, making it a commuter base for the city, and is about 141 miles from London. Hathersage has a population of around 1046 people, living in a variety of housing types, predominantly semi-detached homes.
Across Derbyshire and around Hathersage: fuel drain cover
The teams answering petrol in diesel call-outs in Hathersage, in the S postcode area, also work the places near it, Leadmill, Hathersage Booths and Offerton among them. The vehicle doesn't need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Hathersage: still at the pump?
The best spot there is, then — that is where you are. Keep it off. Call.