How Worried Should You Be? Petrol in a Diesel Car in Horn Park
Far less than you likely are, provided it hasn't been started. "Have I wrecked it?" is the first thing everyone around Horn Park asks, and the honest answer is generally no, because petrol resting in a diesel tank hurts nothing until it is dragged through your fuel system — by ignition priming, by your starter, or by driving. Leave the engine off then phone Petrol in Diesel — that is how you keep it that way. What petrol really does to a diesel, how to judge how far it's travelled, and how to stop it from happening a second time: that is the remainder of this page.
Petrol in a diesel: what does it do to the engine?
Passing through an engine, diesel is doing two things at once. Before it burns, it lubricates — then it burns. Designed to extremely fine tolerances, your injectors and the pump depend on your diesel moving through them to stop their surfaces wearing against one another.
Petrol handles the first task poorly and the second not at all. The knocking comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the protection your system depends on, and any pump running on such a mix is wearing itself.
Put those together and the shape of the problem is plain. Not contact but circulation is what causes the harm. Where the petrol is only in the tank, it is an issue of fuel, nothing more. After the pump has been working on that petrol, a mechanical fault has begun: whatever is shed by a pump that's wearing down is carried onward to the injectors with the fuel.
How bad is petrol in a diesel? Four scenarios our engineers see in Horn Park
Fuelled but not once started — the best it gets. At a forecourt, and genuinely only there, that petrol is still confined to the tank — because anywhere else your car was driven to get to it. The job is draining and purging on the spot.
Ignition on, or started for a moment. Your system has been primed, so petrol has left that tank and reached the fuel filter and your lines. That is generally still an easy task — a drain, a flush, and the filter seen to.
A few miles driven, and the pump has spent each of them working on diluted fuel. Distance is only half of it; how hard it was driven counts equally. Either way the work runs to that tank, the fuel lines, the fuel filter and fresh fuel through the whole system. On the school run to Horn Park Primary School, the mileage is small. Very different again: a run to London, under 10 miles away, or some mileage on the M20, under 10 miles from Horn Park, where your engine never stopped labouring hard.
Driven until it protested. Knocking, an uneven idle, smoke, a throttle that has gone soft. That's the motor telling you its fuel has stopped acting like diesel. Stop wherever you are — the verge on Simnel Road, a lay-by, a side street — then leave the vehicle there. The drain and flush-through still come first, and they sort it out: if a vehicle is pulled over soon, lasting damage is very uncommon.
What Horn Park people get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed by topping up — you are left with a fuller tank, still the same mix. The idea behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. At higher pressure, through more precise parts: that is how a current diesel moves its fuel, so the protection counts more, not less.
One myth that catches people out: if it starts and drives, it must be unharmed. Feed diesel to a petrol motor and it usually won't run, and so the motorist stops — and the harm stops with them. A diesel fed petrol generally starts, ticks over and drives away as if nothing has happened, while your pump grinds. Running isn't the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old fix, supposed for another problem. None of what petrol diluted is put back by it — and afterwards, the tank still contains that petrol.
Once the motor has been run, part of that petrol is in your filter and your lines, not that tank — and the next start pulls it right back through your pump. So the myth "drain your tank yourself and you're sorted" doesn't hold. And, a can of petrol drained by the roadside is genuinely dangerous.
How it happens: petrol in a diesel
A careless moment is seldom the cause, and nobody means to do it. The petrol nozzle is the smaller of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol vehicle at all. The forecourt makes it easy, and the slip runs one way.
The moment routine stops matching the vehicle is the moment it occurs. Courtesy car, hire car, or a vehicle that is brand new. A household with one petrol and one diesel on the drive. A forecourt you know, but with its pumps arranged differently. Filling up in a rush on the way to Lee, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist accustomed to petrol: precisely when it occurs. Throw in a back seat full of kids, a phone call or rain, and habit wins.
Horn Park people: how to avoid petrol in a diesel next time
- The label is what matters, so read the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- In a motor you don't know, look inside the flap over your filler or at the cap before the first fill: many motors state the fuel there.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of intending to remember, in a home with one of each.
- It seems daft and it does the trick: on the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- Whilst you are thinking about something else, this is an easy mistake to make — so put the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to reject a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop reading the petrol pump.
- Noticing it mid-fill? Stop at once. A thinner mix results from less petrol in the tank, but the next step remains the same: do not crank it.
Already put petrol in a diesel in Horn Park?
In that case, there's just a short order of things. Leave it unstarted, with your ignition off as well. If you are still at the forecourt — Esso Express or anywhere else — ask the staff to help you roll it clear of the petrol pump. Next, 0333 366 0103. We will ask what got in, about how much, and if it has been run.
Say so if it was AdBlue instead of petrol: it is a different problem, with its own page for Horn Park, because AdBlue brings corrosion and deposits instead of lost lubrication.
Horn Park petrol in a diesel tasks: why one costs more than another
The four scenarios above are four different jobs, so no single price for this would be honest. Mostly, your cost shifts with which situation you're in. After that it's the share — how much petrol was put in against how much that tank takes — and then where your car is and whether a technician can get to it safely.
Three questions come first, before quoting, instead of after — what went in, how much, has it run — and this is the reason. A range becomes a straight figure once the answers are in.
About Horn Park and its setting
Horn Park is a suburban area in south east London, situated near the River Thames at an elevation of 41 metres. Horn Park is located close to several other suburban areas, including Middle Park, Lee, and Grove Park. Horn Park has a population of approximately 7434 people and is characterised by semi-detached housing. Horn Park is around 7.8 miles from central London, making it a commuter-friendly location.
Horn Park and Greater London: where our fuel drain cover runs
Middle Park, Lee and Grove Park are among the locations near Horn Park that the same vans work, answering petrol in diesel jobs across Horn Park's SE postcode area. The car does not need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the petrol pump around Horn Park, still?
Nothing beats it: that is where you now are. Keep it off. Ring.