Should You Worry? Petrol in a Diesel Car in Dudbridge
Less than you likely are, if it hasn't been started. Everyone in Dudbridge begins with "have I ruined it?", and the fair answer is usually no: petrol resting inside that tank of any diesel remains harmless till priming, cranking or driving pulls it into the fuel system. To keep it that way, call Petrol in Diesel and leave your engine switched off. Further down, 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.
What petrol in a diesel does to the motor
Passing through an engine, diesel is doing two jobs at the same time. It protects to begin with, and after that does it burn. Designed to extremely fine gaps, the injectors and the pump rely on the diesel flowing through them to keep their surfaces from wearing against one another.
Petrol handles the first job poorly and the second not at all. It is runnier than diesel and strips away the protection your fuel system depends on, and so a pump running on a petrol mix is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the knocking comes from.
Taken together, they make clear what shape the trouble has. The damage is done by movement, not by contact. Any tank with petrol in it is a fuel fault. Once your pump has been labouring on that petrol, a mechanical issue has begun: anything shed by a pump that's wearing travels downstream to your injectors with your fuel.
How serious is petrol in a diesel? Four situations our engineers see in Dudbridge
Filled up, and never started: nothing beats it. On a forecourt, and truly only there, that petrol is still limited to that tank — since anywhere else the car was driven to reach it. The job is draining and rinsing on the spot.
Ignition on, or started for a second. Petrol has come out of that tank and got to your filter and your lines, because your system has been bled. Drain, flush, deal with your filter: still normally simple.
A few miles driven, and your pump has spent each of them working on diluted fuel. Tank, lines, filter, then fresh fuel put through the entire system: that is the work, and the way your car was driven counts as much as the miles. Short trips, such as the school run to St Matthew's Church of England Primary School, are one matter. Any distance on the M5, under 5 miles from Dudbridge, means the engine working hard throughout, and a run to Gloucester, under 10 miles away, makes a very different job as well.
Knocking, a ragged idle, smoke, a throttle gone soft: driven until it complained. That is the engine telling you its fuel has stopped acting like diesel. Whether it is the verge on Selsley Hill, a lay-by or a side road, stop there and leave it. What goes first is still the drain and flush-through, and that sorts it out, with lasting damage very rare when a car is stopped early.
Petrol in a diesel myths Dudbridge drivers hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. A diesel fuel system does not tolerate petrol by percentage in the way that guidance assumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. More precise components and higher pressure are how a newer diesel runs its fuel, and that makes the protection matter more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches motorists. The driver of a petrol engine fed diesel usually stops, since it will not run, and the damage stops with them. A diesel fed petrol normally starts, idles and drives away as if nothing has happened, while your pump grinds. Being able to run isn't the same as being fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate issue. What petrol has thinned stays weakened, and the petrol remains in that tank regardless.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol sits in your filter and lines, waiting to go right back through the pump at the next start. Besides, petrol drained into a can by the road is truly risky.
How does petrol in a diesel happen?
It is rarely carelessness, and nobody does it on purpose. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol car at all. The forecourt makes it easy, and the mistake runs one way.
The moment routine stops matching the vehicle is the moment it takes place. Courtesy car, hire car, or a motor that is new. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps arranged differently. A train to catch, and a hurried fill en route to Stroud. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist used to petrol: exactly when it happens. Your hand does what it has always done once you add rain, a phone call or a back seat full of children.
How to prevent petrol in a diesel at your next fill-up in Dudbridge
- A green handle for unleaded and black for diesel is usual in the UK — but not on each forecourt. Go by the label on the pump, not the colour.
- In a car you do not know, look inside the flap over the filler or at the cap before your first fill: plenty of vehicles print the fuel type there.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key when a house has one of each. So label it.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car gets its first tank. It seems silly. It does the trick.
- Whilst you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to refuse a petrol nozzle, and aftermarket devices are available for the remainder. Treat it as a safety net, and keep reading the petrol pump.
- Stop as soon as you notice. Less petrol inside that tank makes a thinner blend. It doesn't change what to do next, which is still not to fire it up.
Dudbridge: already put petrol in a diesel?
Short and simple, then, is the order of things. Leave it unstarted, with the ignition switched off as well. Ask the attendants to help you roll it clear of the pump if you're still on the forecourt, whether that is Esso or somewhere else. Then ring 0333 366 0103 and tell us what got in, about how much, and if it has run.
If it was AdBlue rather than petrol, say so. That's a separate problem — corrosion and deposits rather than lost lubrication — and it has its own page for Dudbridge.
Why one petrol in a diesel job in Dudbridge costs more than another
There's no fair single price for this, since the four situations above are four different jobs. Chiefly, your cost shifts with which one you are in. Two things follow that: the petrol that was put in as a share of what the tank holds, then the spot the car is in and whether a technician can reach it safely.
Three questions come first, before any quote, rather than after — what went in, how much, has it run — and this is the reason. A range turns into a straight figure when the answers are in.
About Dudbridge itself
Dudbridge is a suburban area in Gloucestershire, situated on the riverside at an elevation of 41 metres, with semi-detached housing being the predominant type of accommodation. Dudbridge lies near the city of Gloucester, approximately 8.7 miles away, and is close to nearby places such as Cainscross, Rodborough, and Selsley. Dudbridge is home to around 3200 residents and forms part of the wider Gloucester urban area. Dudbridge is located in the South West region of England, about 92.1 miles west of London.
Across Gloucestershire and around Dudbridge: fuel drain cover
The teams answering petrol in diesel call-outs in Dudbridge, in the GL postcode area, equally work the spots near it, Cainscross, Rodborough and Selsley among them. No need to move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
In Dudbridge and still at the pump?
The best spot there is, then — that is where you are. Phone, and leave it switched off.