Breage: Petrol in a Diesel Car? How Worried to Be
Probably less than you are now — as long as no one has started it. "Have I ruined it?" is the first question anyone in Breage asks, and the honest answer is generally no, because petrol left in a diesel tank hurts nothing until it is dragged through the fuel system — by ignition priming, by the starter, or by being driven. Petrol in Diesel is who to ring, with your motor kept off, and so it stays that way. What petrol actually does to a diesel, how to judge how far it has gone, and how to keep it from happening again: that is the rest of this page.
What petrol in a diesel does to the motor
On its way through an engine, diesel has two tasks. It protects first, and after that does it burn. What keeps the surfaces inside the high-pressure pump and the injectors from grinding against each other is your diesel passing through them — they are built to very fine clearances.
The second job petrol does not do at all, and the first it does poorly. A pump working on a petrol mix is wearing itself out, since petrol is runnier than diesel and takes away the protection the fuel system depends on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that is where any knocking comes.
Put those together and the shape of the problem is clear. Not contact but movement is what does the harm. Where the petrol is only inside the tank, it is an issue of fuel, nothing more. After the pump has been working on that petrol, a mechanical problem has begun: anything shed by a pump that is grinding travels downstream to your injectors with your fuel.
Four situations our technicians see in Breage: how bad is petrol in a diesel?
The best case there can be: filled up, not once started. On a forecourt, and truly only there, that petrol is still confined to your tank — since anywhere else your car was driven to reach it. The task is draining and rinsing on the spot.
Your ignition switched on, or a brief start. Petrol has come out of the tank and got to the fuel filter and the lines, because the fuel system has been primed. Drain, flush, see to the fuel filter: still normally straightforward.
Driven a few miles. Now the pump has spent these miles labouring on diluted fuel. The work is the tank, the lines, the fuel filter and fresh fuel through the whole system, and how hard your car was driven matters as much as how far. A school run to Breage CofE Primary School is one thing. Getting as far as Truro, under 25 miles away, makes a very different task — as does any mileage on the M5, over 50 miles from Breage, with your engine labouring hard all the way.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The fuel is not acting like diesel any more, and the motor is telling you. Leave it wherever it stops: a lay-by, a quiet street, the verge on Pellor Road. What goes first is still the drain and flush-through, and that takes care of it, with lasting damage very unusual when a car is pulled over quickly.
Petrol in a diesel stories Breage people hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing is removed when you top up — the tank just carries more of the same blend. That advice assumes a diesel fuel system handles petrol by percentage. It does not.
Not so: a current diesel copes with a bit of petrol. If anything, the opposite. More precise parts and higher pressure are how a current diesel runs its fuel, and that makes the protection matter more, not less.
"It starts, it drives, and so there is no harm" — the myth that trips up most motorists than any other. Diesel in a petrol motor generally means a motor that won't run: the driver stops, and so does the damage. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump grinds. Being able to run isn't proof of being fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different problem. It doesn't put back what petrol has weakened, and the petrol is still in the tank after that.
Myth: "Drain that tank yourself and you are sorted." Once the motor has been run, some of the petrol is no longer in that tank: it is in the filter and your lines, and it goes right back through your pump at the next start. Also, a can of petrol drained by the roadside is genuinely hazardous.
Why petrol in a diesel occurs so easily
No one does it on purpose, and it is rarely carelessness. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol car. That's how the forecourt makes it straightforward.
The moment routine stops matching your car is the moment it takes place. A new car, a hire car or a courtesy car. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps arranged differently. A hurried fill on the way to St Erth with a train to catch. The first fill-up in a diesel Volkswagen Passat after years of driving petrol is precisely the moment it takes place. With rain, a call arriving, or a car full of children to deal with, the hand just does what it always has.
Preventing petrol in a diesel next time you fill up in Breage
- A green handle for unleaded and black for diesel is normal in the UK — but not on every forecourt. Go by the label on the petrol pump, not the colour.
- Plenty of motors state the fuel type inside your filler flap or on the cap, and so check there on your first fill in a vehicle you do not know.
- Label the key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- Before the nozzle comes off the petrol pump the first time you fuel a hired or new motor, say "diesel" aloud. Silly, yes, but it works.
- Tuck your phone away. This is an easy mistake to make while you are thinking about something else.
- Add-on devices are available for vehicles without one, and some diesels come with a filler that will not take a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label.
- As soon as you notice, stop: less petrol in your tank means a thinner mix. What to do next does not change, though — still don't fire it up.
Already put petrol in a diesel in Breage?
Then the order of things is short. Leave it unstarted, with the ignition switched off as well. Ask the staff to help you roll it away from the petrol pump if you're still at the forecourt, whether that is Pace or somewhere else. Next, 0333 366 0103. We'll ask what went in, roughly how much, and if it's been run.
Corrosion and deposits form the issue with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and read its own Breage page.
Why one petrol in a diesel task in Breage costs more than another
There is no fair single quote for this, since the four scenarios above are four separate tasks. Which of them you are in is mostly what shifts the cost. After that it's the share — how much petrol went in against how much the tank takes — and after that where your car is and whether a van can get to it safely.
That's why our engineers ask three queries before costing instead of after: what was put in, how much, and whether it's run. Their replies are what change a range into one firm number.
About Breage itself
Breage is a small village in Cornwall, situated on the coastal side of the Lizard Peninsula at an elevation of around 100 metres. Breage sits near the villages of Trevena and Trew, and is approximately 16 miles from the city of Truro. Breage has a population of around 622 people, with a predominance of semi-detached housing. Breage is located about 247 miles west of London, in the South West region of England.
Fuel drain cover across Cornwall, Breage included
The teams answering petrol in diesel call-outs in Breage, in the TR postcode area, also work the places near it, Trevena, Trew and Penhale Jakes included. The car does not need to move to us: we drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Breage: still at the pump?
Then you're in the best position there is. Turned off it remains; then phone.