How Worried Should You Be? Petrol in a Diesel Car in Chilbolton
Far less than you probably are, if it hasn't been started. Till the ignition primes your pump, your starter turns, or the vehicle is driven, petrol in a diesel tank simply waits there and does nothing. Which means the truthful reply to the first Chilbolton question — "have I ruined it?" — normally no. Petrol in Diesel is who to phone, with the motor left off, so it remains that way. The rest of this page sets out what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you a second time.
What petrol in a diesel does to the motor
Two tasks fall to diesel on its route through a motor. It lubricates first, and after that does it burn. The high-pressure fuel pump and the injectors are built to very fine gaps, and the diesel passing through them is what stops those surfaces from wearing against one another.
Petrol handles the first task poorly and the second not at all. Being less viscous than diesel, petrol strips away the protection a fuel system needs, leaving a pump running on the blend wearing itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the clattering.
The shape of the trouble is plain when you put those together. The harm is done by movement, not by contact. Petrol in a tank is a fuel problem. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the fuel injectors further on.
Petrol in a diesel in Chilbolton: how bad is it? Four cases
Filled up, and never started: no case is better. That petrol is in that tank and only the tank, and the job is a drain and a flush where your car stands. This is the one situation that can only truly occur at a forecourt, since anywhere else your car has been driven to get there.
Your ignition turned on, or a short start. With your system primed, the fuel lines and filter now hold petrol that has come from that tank. That's usually still a straightforward task — a drain, a flush, and the fuel filter dealt with.
A couple of miles driven, and your pump has spent each of them running on thinned fuel. How hard your car was driven counts as much as how far, and the work takes in your tank, the lines, the fuel filter and fresh fuel through the entire circuit. On the school run to Wherwell Primary School, the miles is short. Very different again: a run to Winchester, under 10 miles away, or some miles on the M3, under 10 miles from Chilbolton, where the engine never stopped labouring hard.
Driven on until it complained — knocking, smoke, a lumpy idle, a soft throttle. That is your motor telling you its fuel no longer is behaving like diesel. Whether it is the verge on Village Street, a lay-by or a side street, stop where you are then leave it. The drain and flush still come first, and they deal with it: if a car is stopped early, long-term damage is very unusual.
Myths Chilbolton motorists hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." A fuller tank of the same mix is all you get, since topping up removes nothing. The assumption behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: a newer diesel copes with a bit of petrol. If anything, the opposite. At higher pressure, through more precise components: that is how a modern diesel moves its fuel, so the lubrication counts more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that fools motorists. The motorist of a petrol engine fed diesel usually stops, since it will not run, and the damage stops with them. Feed petrol to a diesel and it usually starts, ticks over and drives away as if nothing has happened — all the while its pump wears. A running engine doesn't mean fine.
An outdated workaround for a separate problem lies behind this one. Myth: "Add some two-stroke oil and drive it home." The petrol is still in your tank afterwards, and whatever it has weakened is not put back.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol sits in the filter and lines, waiting to go right back through the pump at your next start. On top of that, petrol cleared into a can by the road is genuinely risky.
Petrol in a diesel: how does it take place?
A careless moment is rarely the cause, and no one means to do it. A diesel nozzle generally will not go into a petrol vehicle, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error straightforward, and only in one direction.
The moment habit stops matching your car is the moment it occurs. Courtesy car, hire car, or a motor that's new. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. A train to catch, and a rushed fill en route to Andover. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver accustomed to petrol: exactly when it occurs. With rain, a call coming in, or children to deal with, your hand just does what it has always done.
How to prevent petrol in a diesel on your next fill-up around Chilbolton
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Check the petrol pump's label; the colour is only a clue.
- Plenty of motors state the fuel type inside your filler flap or on the cap, so check there on your first fill in any vehicle you do not know.
- 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 intending to remember.
- "Diesel", aloud, before you pick up the nozzle — each 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, so tuck your phone away then keep your mind on the pump.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to refuse a petrol nozzle, and aftermarket devices exist for the rest. Count it as a backstop, then keep reading the petrol pump.
- As soon as you notice, stop: less petrol in that tank means a thinner mix. What to do next doesn't change, though — still do not start it.
Petrol already in a diesel in Chilbolton? Start here
The order of things is short, then. Don't turn your ignition on, and do not crank it. The attendants on the forecourt — whether at BP itself or wherever you filled up — will usually help roll it clear of the pump if you ask. Next, 0333 366 0103. We will ask what got in, about how much, and if it's been run.
If it was AdBlue rather than petrol, say so. That's a separate issue — corrosion and deposits rather than lost protection — and it has its own page for Chilbolton.
What makes one Chilbolton petrol in a diesel job cost more than the next
The four situations above are four different tasks, so no single price for this would be fair. Which of them you are in is mostly what moves your cost. After that it is the proportion — how much petrol was put in against how much that tank takes — and after that where the car is and whether our van can reach it safely.
What went in, how much, and if it has run — three questions we ask before pricing, not after, for precisely that reason. Their answers are what turn a range into one firm number.
About Chilbolton
Chilbolton is a small village in Hampshire, situated on the banks of the River Test at an elevation of around 45 metres. Chilbolton has a population of approximately 570 people and is characterised by predominantly detached housing. Chilbolton is located near the cities of Winchester and Southampton, and is close to nearby villages such as Wherwell and Fullerton. Chilbolton sits in a rural area, with the city of London around 61 miles to the east.
Fuel drain cover around Chilbolton and across Hampshire
Wherwell, Cottonworth and Fullerton are among the places around Chilbolton that the same teams work, answering petrol in diesel calls across Chilbolton's SO postcode area. The car doesn't need to move to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the petrol pump in Chilbolton, right now?
Then you're in the best spot there can be. Switched off it remains; then call.