Wansford: Petrol in a Diesel Car? How Worried to Be
Likely less than you already are — as long as no one has started it. Everyone in Wansford starts with "have I ruined it?", and the honest answer is generally no: petrol left in your tank of a diesel remains harmless until priming, cranking or driving draws it into the fuel system. Keep it like that: leave your motor off and call Petrol in Diesel. Further down, you will find what petrol actually does inside a diesel, how far it may have got, and how to stop it happening to you a second time.
What petrol in a diesel does to the engine
Two jobs fall to diesel on its journey through a motor. Oiling comes before burning; it does both. Made to very fine gaps, the injectors and the pump rely on the diesel moving through them to keep their surfaces from wearing against one another.
The second task petrol does not do at all, and the first it does badly. It is thinner than diesel and takes away the lubrication the system depends on, so a pump running on a petrol blend is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the clattering comes from.
The shape of the trouble is clear once you put those together. It's movement that causes the damage, not contact. Where that petrol is only in your tank, it's a fault of fuel, nothing more. After the pump has been labouring on that petrol, a mechanical fault has begun: whatever is shed by a pump that is grinding is carried onward to your injectors with your fuel.
Wansford, petrol in a diesel: four situations, from mild to major
The best case there can be: filled up, never started. Being at a forecourt is what makes this the case: elsewhere, your car has been driven there to begin with. With the petrol held inside that tank alone, it's emptied and purged right where it stands, and nothing more is needed.
A moment's running, or merely the ignition on. With the system primed, the lines and filter now hold petrol that came from your tank. Still normally straightforward: drain, flush, and the fuel filter sorted.
The pump has worked a couple of miles on weakened fuel — that is what driving the car meant. Miles is only half of that; how hard it was driven counts just as much. Either way the work includes your tank, your lines, the fuel filter and clean fuel through the entire system. The school run to Nassington Primary School is one thing. A run as far as Peterborough, under 10 miles away, is a very different task. So is any mileage on the Great North Road, under 10 miles from Wansford, where the engine has been working hard the whole time.
Driven till it complained. Rattling, an uneven idle, smoke, a throttle that has gone soft. The motor is telling you your fuel is no longer acting like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Yarwell Road. What comes first is still the drain and flush-through, and that deals with it, with permanent damage very unusual when a car is pulled over soon.
Petrol in a diesel stories Wansford drivers hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Topping up takes out nothing; it gives you a bigger tank of the same mix. A diesel fuel system doesn't accept petrol by percentage in the way that advice supposes.
Myth: a modern diesel copes with a bit of petrol. Rather, the reverse. A newer diesel sends its fuel through finer parts at higher pressure, which makes the lubrication matter more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that fools drivers. Any petrol motor fed diesel generally won't run, and so the motorist stops and the damage stops with them. Whilst the pump wears, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Running is not the same as fine.
An old fix for a distinct fault lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has weakened remains diluted, and that petrol stays in that tank anyway.
If your engine has been run, part of that petrol is in the fuel filter and the fuel lines, not that tank — and your next start pulls it straight back through the pump. So the myth "drain your tank yourself and you are sorted" does not stand up. Emptying petrol into a can at the kerbside is also really dangerous.
How it happens: petrol in a diesel
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle generally will not fit a petrol motor, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and only in one direction.
When routine and the car stop matching, it occurs. Hire cars, courtesy cars, and vehicles that are new to you. One petrol and one diesel on the drive of the same household. A forecourt you know, only with its pumps arranged differently. Racing for a train at Stamford and fuelling up en route. A new-to-you diesel Volkswagen Passat, its first fuelling, and a motorist accustomed to petrol: precisely when it occurs. The hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
Wansford motorists: how to avoid petrol in a diesel next time
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Check the petrol pump's label; the colour is just a hint.
- In a vehicle you do not know, look inside the flap over the filler or at the cap before the first fill: plenty of motors state the fuel type there.
- A coloured fob or a sticker on the diesel's key does more than any amount of intending to remember, for a household with one of each.
- Before the nozzle comes off the petrol pump the first time you fuel a hired or new motor, say "diesel" aloud. Silly, yes, yet it does the trick.
- Tuck your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Some diesels come with a filler built to block a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the petrol pump.
- Less petrol means a thinner mixture, so stop the moment you realise — while remembering that your next stage is unchanged. It's still not to crank it.
Petrol already in a diesel in Wansford? Begin here
Then the order of things is short. Don't crank it, and don't turn the ignition on. If you're still at the forecourt — BP or anywhere else — ask the attendants to help you roll it clear of the pump. Then ring 0333 366 0103 and tell us what got in, about how much, and whether it's run.
If it was AdBlue and not petrol, say so. That is a different fault — corrosion and deposits instead of lost protection — and it has its own page for Wansford.
Why one petrol in a diesel task around Wansford costs more than another
There's no honest single price for this, since the four scenarios above are four separate tasks. What moves your cost is chiefly which of them you're in. The share counts next, meaning how much of the tank is petrol, followed by the location of the vehicle and whether reaching it is safe for our van.
Ahead of any quote, not after, we ask three queries: your fuel that went in, the volume, and if it's run. That is why. A range turns into a straight figure when those answers are in.
About Wansford, briefly
Wansford is a village situated on the banks of the River Nene in Cambridgeshire, with a low elevation of around 22 metres. Wansford lies near the city of Peterborough, approximately 7 miles to the east, and is surrounded by other small villages such as Thornhaugh and Yarwell. Wansford has a population of around 631 people, predominantly living in detached houses. Wansford is located about 75 miles north of London, in the eastern part of England.
Fuel drain cover in Wansford and across Cambridgeshire
Petrol in diesel jobs in Wansford — part of the PE postcode area — go to teams that likewise cover the spots round it, Thornhaugh, Yarwell and Stibbington 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 pump in Wansford?
The best place there is, then — that is where you are. Keep the vehicle switched off, and ring.