Petrol in a Diesel Car in Kings Furlong: How Worried Should You Be?
Likely less than you are now — provided nobody has started it. Everyone in Kings Furlong begins with "have I ruined it?", and the fair answer is generally no: petrol resting in the tank of any diesel remains harmless until priming, cranking or driving pulls it into your fuel system. To keep it that way, ring Petrol in Diesel and leave your motor alone. Read on for three things: the effect petrol has inside a diesel motor, the clues of how far it has got, and the way to make sure you don't repeat it.
Inside the engine: what petrol in a diesel does
Passing through an engine, diesel is doing two things at the same time. It combusts, and before it combusts it lubricates. The high-pressure fuel pump and the injectors are made to very fine gaps, and your diesel passing through them is what keeps those surfaces from wearing down against one another.
Poorly at the first, not at all at the second: that's petrol. The clattering comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection your system depends on, and any pump working on that mix is wearing itself.
The shape of the problem is plain when you put those together. Not contact but movement is what causes the damage. Where the petrol is only inside the tank, it is an issue of fuel, nothing more. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to your injectors downstream.
How bad is petrol in a diesel? Four scenarios we see in Kings Furlong
Filled up, never started. The best case there can be. At a forecourt, and genuinely only there, the petrol is still limited to the tank — since everywhere else your car was driven to reach it. The task is emptying and flushing on the spot.
Your ignition turned on, or a short start. With the system primed, your lines and filter already hold petrol that has come from that tank. Drain, flush, see to your filter: still normally easy.
Driven a few miles. Now your pump has spent those miles running on weakened fuel. Tank, lines, filter, then fresh fuel put through the whole circuit: that's this work, and the way the car was driven counts as much as the distance. On the school run to Kings Furlong Junior School, the miles is short. Very different once more: a trip to Winchester, under 25 miles away, or some mileage on the M3, under a mile from Kings Furlong, where the motor never stopped working hard.
Driven until it protested. Knocking, a lumpy idle, smoke, a throttle that has gone soft. That's your engine telling you its fuel has stopped acting like diesel. Whether it is the verge on Kings Furlong Drive, a lay-by or a side road, stop there then leave it. The fuel drain and flush-through still come first, and they deal with it: when a vehicle is stopped quickly, lasting damage is very rare.
What Kings Furlong people get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Topping up takes out nothing; it gives you a bigger tank of the same mix. The assumption behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A newer diesel can cope with a bit of petrol." Finer parts and higher pressure are how a newer diesel runs its fuel, and that makes the protection matter more, not less.
"It starts, it drives, and so no harm done" — the myth that catches more people than any other. The motorist of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the harm stops there. Feed petrol to a diesel and it generally starts, idles and drives away like nothing happened — all while its pump is wearing. A running engine doesn't mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an old fix for a distinct issue. That petrol is still in the tank afterwards, and what it has weakened is not put back.
Once the motor has run, part of that petrol is in the filter and your lines, not that tank — and the next start sends it right back through the pump. So the myth "drain that tank yourself and you are sorted" doesn't stand up. It is also truly risky to drain petrol into a can by the kerbside.
How does petrol in a diesel happen?
A careless moment is seldom the cause, and no one means to do it. A diesel nozzle mostly won't fit a petrol motor, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake easy, and just in one direction.
When habit and the car stop matching, it occurs. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. Filling up in a hurry en route to Basingstoke, with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is precisely the moment it occurs. Add rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Avoiding petrol in a diesel next time you fill up around Kings Furlong
- A green handle for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Go by the label on the pump, not the colour.
- Many cars state the fuel inside your filler flap or on the cap, so check it on your first fill in a vehicle you do not know.
- Mark the key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump. It sounds daft and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so tuck your phone away and keep your mind on the petrol pump.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to reject a petrol nozzle, and aftermarket devices exist for the remainder. Treat it as a safety net, then keep checking the petrol pump.
- Stop as soon as you realise. Less petrol in that tank makes a thinner blend. It doesn't change what to do next, which is still not to fire it up.
Petrol already in a diesel in Kings Furlong? Start here
The order of things is short, then. Don't switch your ignition on, and don't crank it. If you're still at the forecourt — Morrisons or anywhere else — ask the attendants to help you roll it away from the petrol pump. What was put in, roughly how much, and whether it has run: tell us those when you call 0333 366 0103.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different issue — Kings Furlong has a page all for it.
One petrol in a diesel job in Kings Furlong costs more than another. Why?
The four scenarios above are four different tasks, so no single price for this would be fair. Which of them you are in is chiefly what shifts the cost. Where the vehicle is counts too, and whether a technician can safely get to it, after the ratio of petrol to what the tank holds.
Before any quote, not after, come three queries: the fuel that got in, the amount, and whether it has run. That's why. Those replies are what turn a range into one firm number.
About Kings Furlong, briefly
Kings Furlong is a suburban area in Hampshire, situated inland at an elevation of 87 metres, and forms part of the larger Basingstoke urban area. Kings Furlong is located near the suburbs of South Ham and Viables, and is approximately 16 miles from the city of Winchester. Kings Furlong has a population of around 6436 people, predominantly living in terraced housing. Kings Furlong is also within commuting distance of London, being around 45 miles from the capital.
Fuel drain cover across Hampshire, Kings Furlong included
Petrol in diesel call-outs around Kings Furlong — part of the RG postcode area — go to teams that also cover the spots about it, South Ham, Viables and Basingstoke among them. 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 Kings Furlong and still at the pump?
The best spot there is, then — that is where you are. Leave it switched off, then ring.