How Worried Should You Be? Petrol in a Diesel Car in Kingsclere
Far less than you likely are, if it has not been started. Everyone around Kingsclere begins with "have I wrecked it?", and the fair answer is generally no: petrol left in the tank of a diesel remains harmless until priming, cranking or driving pulls it into the system. Keep it like that: leave the motor off then call Petrol in Diesel. 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.
The engine and petrol in a diesel: what goes on
On its way through an engine, diesel has two tasks. It ignites, and before it ignites it protects. Your high-pressure pump and your injectors are designed to extremely fine clearances, and the diesel passing through them is what stops those surfaces from wearing against one another.
Petrol handles the first task badly and the second not at all. It's thinner than diesel and removes the lubrication the fuel system hinges on, so a pump running on a petrol blend is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the rattling comes from.
The shape of the trouble is clear once you put those together. The harm is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel issue. Whatever a worn pump sheds goes on, borne by your fuel, into the injectors downstream, which is why a pump that has been working on that petrol is where a mechanical fault starts.
Petrol in a diesel around Kingsclere: how bad is it? Four situations
Filled up, never started. The best case there can be. Being at a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol held inside your tank alone, it is emptied and purged right where it stands, and nothing more is needed.
Ignition on, or started for a moment. With your system primed, your lines and filter already hold petrol that came from that tank. Usually nothing more than clearing, rinsing and seeing to the filter, so still simple.
Driven a couple of miles. Now the pump has spent those miles labouring on thinned fuel. Miles is only half of that; how hard it was driven matters equally. Either way the work includes your tank, the fuel lines, your filter and fresh fuel through the whole circuit. Driving the children to Kingsclere Church of England Primary School is one kind of trip. Very different a second time: a run to Winchester, under 25 miles away, or any distance on the M3, under 10 miles from Kingsclere, where the engine kept running hard.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The engine is telling you the fuel is no longer acting like diesel. Stop wherever you are — the verge on Ashford Hill Road, a lay-by, a side street — and leave it where it is. Lasting damage is very rare if a vehicle is pulled over early, and the fuel drain and flush that still go first sort it out.
Petrol in a diesel myths Kingsclere people hear
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing comes out when you top up — the tank just carries more of the same mixture. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance supposes.
"Current diesels can handle a little petrol" — a myth, and closer to the opposite. At higher pressure, through finer components: that's how a modern diesel handles its fuel, so the lubrication counts for more, not less.
This is the one that catches drivers. Myth: "If it starts and drives, there is no harm done." The driver of a petrol motor fed diesel usually stops, since it will not run, and the damage stops with them. Feed petrol to a diesel and it generally fires up, ticks over and pulls away like nothing happened — all while its pump is wearing. Running isn't the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different issue. That petrol is still in the tank after that, and what it has thinned is not put back.
If the engine has been run, part of the petrol is in the fuel filter and the fuel lines, not the tank — and your next start sends it straight back through your pump. So the myth "drain your tank yourself and you are sorted" doesn't stand up. Clearing petrol into a can at the roadside is also truly risky.
Petrol in a diesel: how does it happen?
Carelessness is seldom the cause, and no one means to do it. One way only, because of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one mostly won't fit a petrol motor. That is how the forecourt makes it easy.
Habit and the vehicle getting out of step is when it happens. A new vehicle, a hire car or a courtesy car. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. Filling up in a rush en route to Thatcham, with a train to catch. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. Throw in rain, a phone call or a back seat full of children, and your hand repeats what it has always done.
Next time you fill up around Kingsclere: avoiding petrol in a diesel
- The label is what matters, and so check the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- In a motor you do not know, look inside the flap over the filler or at the cap before the first fill: many motors print the fuel type there.
- Mark the key. In a household with one of each, a coloured fob or a sticker on your 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" out loud before you take the nozzle off the pump. It seems daft and it works.
- While 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 have a filler built to block a petrol nozzle, and add-on devices exist for vehicles without one. They are a safety net, not a reason to stop checking the pump.
- Less petrol means a weaker mixture, and so stop as soon as you notice — while remembering that the next stage is unchanged. It's still not to fire it up.
Petrol already in a diesel in Kingsclere? Start here
In that case, there's just a short order of things. Don't start the vehicle, and don't turn the ignition on. If you're still at the forecourt — Shell or anywhere else — ask the attendants to help you push the car away from the petrol pump. Then ring 0333 366 0103 and tell us what got in, about how much, and if it's run.
If it was AdBlue and not petrol, say so. That is a separate issue — corrosion and deposits and not lost protection — and it has its own page for Kingsclere.
Why one petrol in a diesel task in Kingsclere costs more than another
A fair single quote does not exist here: four situations, four separate tasks. Mostly, the cost shifts with which situation you are in. After that it is the proportion — how much petrol got in against how much your tank takes — and then where the vehicle is and whether a van can get to it safely.
Ahead of any quote, not after, we ask three queries: the fuel that went in, the quantity, and whether it's run. That's why. The answers change a range into a straight figure.
About Kingsclere, briefly
Kingsclere is a village in north Hampshire, situated in a rural area with nearby woodlands and common land, and is located approximately 109 metres above sea level. Kingsclere sits near the edge of the North Wessex Downs, an Area of Outstanding Natural Beauty, and is close to the villages of Wolverton and Ecchinswell. Kingsclere has a mix of housing types, but semi-detached homes are predominant in the village. Kingsclere is within commuting distance of major cities, including Winchester and London.
Across Hampshire and around Kingsclere: fuel drain cover
The teams answering petrol in diesel call-outs around Kingsclere, in the RG postcode area, also work the places near it, Wolverton, Kingsclere Woodlands and Ecchinswell included. The car doesn't need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the petrol pump in Kingsclere?
Then you are in the best place there is. Turned off it remains; then ring.