How Worried Should You Be? Petrol in a Diesel Car in Bacon End
Provided it hasn't been started, worry far less than you likely are. Everyone in Bacon End begins with "have I ruined it?", and the honest answer is generally no: petrol resting in that tank of a diesel remains harmless till priming, cranking or driving draws it into your fuel system. To keep the car that way, phone Petrol in Diesel and leave your motor alone. The rest of this page sets out 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 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 tolerances go into your injectors and the high-pressure fuel pump, and just your diesel flowing through keeps those surfaces from grinding together.
Badly at the first, not at all at the second: that is petrol. It is runnier than diesel and strips away the lubrication the fuel system rests on, so a pump running on a petrol mixture is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the rattling comes from.
Put these together and the shape of the trouble is clear. Contact does not do the harm — movement does. Petrol in a tank is a fuel problem. Whatever a worn pump sheds travels on, borne by the fuel, into the injectors further along, which is why a pump that has been working on the petrol is where a mechanical issue starts.
Bacon End, petrol in a diesel: four cases, from mild to major
Fuelled up, never started. The best case there is. Only your tank has petrol in it, so the job is draining your tank and cleaning the fuel system where the car sits. This situation can only really take place at a forecourt: anywhere else, your car got there by being driven.
Your ignition turned on, or a short start. With your system primed, the lines and filter now contain petrol that has come from your tank. Drain, flush, see to the fuel filter: still usually simple.
The pump has spent a couple of miles on thinned fuel — that is what driving the vehicle meant. Tank, lines, filter, then clean fuel put through the entire circuit: that is the work, and the way your car was driven counts as much as the mileage. Driving the children to Great Dunmow Primary School is one kind of trip. Driving as far as Chelmsford, under 10 miles away, makes a very different job — as does any mileage on the M11, under 10 miles from Bacon End, with the motor working hard all the way.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone uneven. The fuel is not behaving like diesel any more, and the engine is telling you. Stop wherever you are — the verge on Bacon End Road, a lay-by, a side street — then leave the vehicle there. The drain and flush still come first, and they take care of it: when a vehicle is pulled over early, long-term damage is very rare.
What Bacon End drivers get told about petrol in a diesel — and the stories in it
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a bigger tank, still the same mix. That guidance supposes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. At higher pressure, through smaller components: that is how a newer diesel handles its fuel, so the protection matters more, not less.
"It starts, it drives, and so there is no harm" — the myth that catches most people than any other. A petrol motor fed diesel normally will not run, so the motorist stops and the harm stops with them. While the pump wears, a diesel fed petrol usually starts, ticks over and drives away as if nothing has happened. Running does not mean fine.
Myth: "Add some two-stroke oil and drive the car home." It is an old fix for a distinct fault. It does not put back what petrol has diluted, and the petrol is still inside that tank afterwards.
The next start draws petrol back round the pump out of your lines and the fuel filter, where some of that sits once the motor has run. That is why a DIY tank drain does not sort it — a myth. On top of that, petrol cleared into a can by the road is truly hazardous.
Why petrol in a diesel happens so easily
Carelessness is seldom the cause, and no one means to do it. A diesel nozzle mostly won't go into a petrol vehicle, yet the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in that direction.
Routine and the car getting out of step is how it takes place. A new car, a hire car or a courtesy car. Two cars on one driveway, one petrol, one diesel. A familiar forecourt with the pumps in a different order. A rushed fill en route to Stansted Airport with a train to catch. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Renault Clio for the first time. Throw in a back seat full of kids, a phone call or rain, and the hand wins.
Preventing petrol in a diesel next time you fill up around Bacon End
- The label is what matters, so check the pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- In a vehicle you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of motors print the fuel type there.
- Label your key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car gets its first tank. It seems daft. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck the phone away then keep your mind on the petrol pump.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to refuse a petrol nozzle, and aftermarket devices exist for the rest. Count it as a backstop, and keep checking the pump.
- The moment you notice, stop: less petrol inside that tank means a weaker mixture. What to do next doesn't change, though — still do not crank it.
Put petrol in a diesel in Bacon End already?
The order of things is short, then. Don't switch the ignition on, and don't crank it. If you're still at the forecourt — Tesco or anywhere else — ask the staff to help you push the car away from the pump. What was put in, about how much, and if it's run: tell us those when you phone 0333 366 0103.
If it was AdBlue rather than petrol, say so. That is a different issue — corrosion and deposits and not lost lubrication — and it has its own page for Bacon End.
One petrol in a diesel job in Bacon End costs more than another. Why?
The four situations above are four separate jobs, so no single quote for this would be fair. What shifts your cost is mostly which of them you're in. Where the vehicle is counts too, and whether a van can safely get to it, after the ratio of petrol to what that tank holds.
What got in, how much, and whether it's run — three questions our technicians ask before pricing, not after, for precisely that reason. Those replies are what change a range into one firm number.
About Bacon End
Bacon End is a small hamlet in Essex, situated inland at an elevation of around 74 metres, and is located approximately 9.6 miles from Chelmsford. Bacon End is characterized by its predominantly detached housing stock and is surrounded by nearby places such as Baconend Green and Philpot End. Bacon End remains a quiet rural community, with High Roding also nearby, and is about 30.4 miles from London.
Across Essex and in Bacon End: fuel drain cover
Bacon End waits in the CM postcode area, and the teams that answer petrol in diesel jobs there work the places around it as well — Baconend Green, Philpot End and High Roding among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots we drain, and your car doesn't need to move to us.
Bacon End: still at the petrol pump?
The best place there is, then — that's where you are. Turned off it remains; then ring.