Osidge: Petrol in a Diesel Car? How Worried to Be
Far less than you probably are, provided it hasn't been started. Until the ignition primes your pump, the starter cranks, or the car is driven, petrol in a diesel tank just sits there and does nothing. Which makes the truthful reply to that first Osidge question — "have I ruined it?" — normally no. To keep the vehicle like that, call Petrol in Diesel and leave the engine alone. What petrol actually does to a diesel, how to judge how far it's travelled, and how to stop it from happening again: that is the remainder of this page.
The motor and petrol in a diesel: what happens
Two tasks fall to diesel on its route round a motor. Before it burns, it protects — then it ignites. What stops the surfaces inside the high-pressure fuel pump and the fuel injectors from grinding against each other is the diesel flowing through them — they are designed to extremely fine gaps.
Poorly at the first, not at all at the second: that is petrol. A pump running on a petrol blend is wearing itself out, because petrol is runnier than diesel and takes away the lubrication the fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where the rattling comes.
The shape of the trouble is plain once you put those together. It's movement that does the damage, not contact. Petrol in a tank is a fuel fault. After your pump has been running on that petrol, a mechanical problem has begun: anything shed by a pump that's wearing down travels downstream to the injectors with the fuel.
Osidge, petrol in a diesel: four situations, from mild to serious
Fuelled up, not once started. The best case there is. On a forecourt, and genuinely only there, the petrol is still confined to that tank — since everywhere else the car was driven to reach it. The job is emptying and cleaning on the spot.
The ignition switched on, or a brief start. Once primed, the fuel system has drawn petrol from that tank as far as the fuel filter and the fuel lines. That's usually still a straightforward job — a drain, a flush, and the fuel filter seen to.
Those few miles on the road meant the pump running on fuel diluted by petrol the whole way. Distance is only half of it; how hard it was driven matters equally. Either way the work runs to your tank, the lines, the fuel filter and clean fuel through the whole system. On the school run to Ashmole Primary School, the miles is short. Driving as far as London, under 10 miles away, makes a very different task — as does any mileage on the M25, under 5 miles from Osidge, with the motor labouring hard the whole time.
Rattling, an uneven idle, smoke, a throttle gone soft: driven until it complained. That's the motor telling you its fuel no longer is acting like diesel. Pull up wherever you are — the verge on Hampden Way, a lay-by, a side street — then leave the car where it is. A car pulled over soon very rarely has long-term damage, as the drain and the flush, which still go first, sort it out.
Myths Osidge people hear about petrol in a diesel
False: topping up to full with diesel makes it fine. It doesn't. A fuller tank of the same mix is all you get, because topping up takes out nothing. The assumption behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Not so: a current diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through more precise components: that is how a newer diesel moves its fuel, and so the lubrication counts more, not less.
The myth that catches drivers out: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it usually won't run, so the motorist stops — and the damage stops with them. Whilst your pump wears, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Running doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct fault. It doesn't put back what petrol has weakened, and the petrol is still in that tank afterwards.
The next start sends petrol back round the pump from the lines and the fuel filter, where some of it sits once your engine has been run. That is why draining your tank yourself does not leave you sorted — a myth. And, a can of petrol drained at the roadside is genuinely hazardous.
How does petrol in a diesel occur?
A careless moment is rarely the cause, and no one means to do it. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol motor at all. The forecourt makes it easy, and the slip runs one way.
Habit and the vehicle falling out of step is when it happens. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. The pumps in a different order on a well-known forecourt. A rushed fill on the way to New Southgate with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it occurs. With rain, a call coming in, or a car full of children to deal with, the hand simply does what it has always done.
Preventing petrol in a diesel next time you fill up around Osidge
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most usually do. Read the petrol pump's label; the colour is only a hint.
- 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 there.
- Mark the key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Silly, yes, yet it does the trick.
- Put your phone away. This is an easy mistake to make while you're thinking about something else.
- Add-on devices are available for motors without one, and some diesels come with a filler that won't accept a petrol nozzle. Helpful — but a backstop at best, never a reason to stop checking the label.
- As soon as you notice, stop: less petrol in that tank makes a thinner mix. What to do next doesn't change, though — still do not start the car.
Already put petrol in a diesel in Osidge?
The order of things is short, then. Don't switch your ignition on, and do not crank it. If you are still on the forecourt — Esso or anywhere else — ask the attendants to help you push the car clear of the pump. Then ring 0333 366 0103 and tell us what went in, roughly how much, and whether it has run.
Say so if it was AdBlue instead of petrol: it is a different issue, with its own page for Osidge, since AdBlue brings corrosion and deposits rather than lost lubrication.
One petrol in a diesel job in Osidge costs more than another. Why?
A fair single quote doesn't exist here: four situations, four separate jobs. Which of them you are in is chiefly what shifts the cost. Where your car is matters too, and whether a technician can safely get to it, after the share of petrol to what the tank holds.
That is why we ask three questions before pricing instead of after: what got in, how much, and whether it has run. The replies turn a range into a straight figure.
About Osidge and its setting
Osidge is a suburban area in north London, situated near the banks of the River Lee Navigation at an elevation of around 56 metres. Osidge is characterised by its semi-detached housing stock and is located approximately 8.5 miles from central London. Osidge borders nearby places such as Brunswick Park, Southgate, and New Southgate, forming part of the wider north London residential area.
Across Greater London and in Osidge: fuel drain cover
Petrol in diesel calls around Osidge — part of the N postcode area — go to teams that also cover the places round it, Brunswick Park, Southgate and New Southgate included. Our engineers drain wherever the vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
In Osidge and still at the pump?
The best position there is, then — that's where you are. Keep it off. Ring.