Wellingborough: Petrol in a Diesel Car? How Worried to Be
Far less than you probably are, provided it hasn't been started. Until the ignition primes the pump, your starter turns, or your vehicle is driven, petrol in a diesel tank simply rests there and does no harm. Which means the honest reply to the first Wellingborough question — "have I ruined it?" — normally no. Leave the motor off then phone Petrol in Diesel — that keeps it that way. Read on for three things: the effect petrol has inside a diesel engine, the clues of how far it has got, and ways to make sure you never repeat it.
The motor and petrol in a diesel: what happens
Two tasks fall to diesel on its route through a motor. Before it combusts, it protects — then it combusts. What stops the surfaces inside your high-pressure pump and the injectors from grinding against each other is your diesel passing through them — they are made to extremely fine clearances.
The second job petrol does not do at all, and the first it does badly. It is runnier than diesel and removes the lubrication the system hinges on, and 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's where the knocking comes from.
Taken together, they make clear the shape the issue has. Contact doesn't do the harm — movement does. Petrol in the tank is a fuel fault. The start of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with the fuel to your injectors beyond it.
Wellingborough, petrol in a diesel: four situations, from mild to serious
Fuelled but not once started — as good as it gets. Just that tank has petrol in it, so the task is clearing the tank and rinsing your system where your car sits. This situation can only truly happen at a forecourt: anywhere else, the car got there by being driven.
Your ignition switched on, or a short start. Petrol has come out of that tank and reached the filter and your lines, because the fuel system has been bled. That is generally still an easy job — a drain, a flush, and your filter dealt with.
The pump now spent a couple of miles on weakened fuel — that is what driving the vehicle does. How hard the car was driven matters as much as how far, and this work takes in your tank, the lines, your filter and fresh fuel through the entire circuit. Driving the kids to Park Junior School, Wellingborough is one kind of trip. Getting as far as Milton Keynes, under 25 miles away, makes a very different task — as does any mileage on the M1, under 15 miles from Wellingborough, with the engine working hard all the way.
Clattering, a ragged idle, smoke, a throttle gone soft: driven until it complained. That is your engine telling you its fuel no longer is acting like diesel. Pull up wherever you are — the verge on Market Street, a lay-by, a side street — then leave the car where it is. The fuel drain and flush-through still go first, and they sort it out: if a car is pulled over quickly, permanent damage is very unusual.
What Wellingborough drivers get told about petrol in a diesel — and the stories in it
False: topping up to full with diesel makes it fine. It does not. Topping up takes out nothing; it gives you a bigger tank of the same mix. Percentage isn't how a diesel fuel system copes with petrol, however much that advice presumes.
If anything, the opposite holds. Myth: "A newer diesel can cope with a bit of petrol." Finer parts and higher pressure are how a modern diesel runs its fuel, and that makes the protection matter more, not less.
"It starts, it drives, so no harm done" — the myth that trips up most people than any other. Diesel in a petrol motor generally leaves a motor that won't run: the motorist 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 wears. Being able to run isn't proof of being fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct fault. The petrol is still inside the tank after that, and whatever it has diluted isn't put back.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol lies in your filter and lines, ready to go straight back through the pump at your next start. It is also truly dangerous to drain petrol into a can by the roadside.
Why petrol in a diesel takes place so easily
On purpose? Never. Through carelessness? Seldom, if ever. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle mostly won't go into a petrol motor at all. So the error runs one way.
It happens when routine and the car stop matching. A new car, a hire car or a courtesy car. Households running one of each, petrol and diesel. Your normal forecourt, its pumps suddenly in a different order. Racing for a train at the nearest station and filling up en route. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it always has.
Avoiding petrol in a diesel next time you fill up in Wellingborough
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Check the pump's label; the colour is just a hint.
- The first fill in an unfamiliar vehicle is the time to check the filler flap — on it, or on the cap, many cars state which fuel they take.
- One of each in the house? Label your key to your diesel — a coloured fob, a sticker — since meaning to remember isn't enough.
- It seems silly and it does the trick: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- Mistakes like this are easy to make whilst your mind is on something else, and so your phone goes away.
- Add-on devices are available for vehicles without one, and some diesels are built with a filler that will not accept a petrol nozzle. Helpful — but a safety net at best, never a reason to stop checking the label.
- Less petrol means a thinner mix, and so stop as soon as you realise — while remembering that the next stage is unchanged. It is still not to start the car.
Petrol already in a diesel in Wellingborough? Start here
Then the order of things is brief. Leave it unstarted, with the ignition off as well. If you are still on the forecourt — Morrisons or anywhere else — ask the staff to help you push it clear of the petrol pump. Ring 0333 366 0103 next, with three answers — the fuel, the approximate volume, and if it has run.
If it was AdBlue rather than petrol, say so. That's a separate issue — corrosion and deposits instead of lost protection — and it has its own page for Wellingborough.
What makes one Wellingborough petrol in a diesel job cost more than the next
The four scenarios above are four different jobs, so no single price for this would be honest. The situation itself does most of the work of moving your cost. Next it's the proportion — how much petrol was put in against how much the tank holds — and then where your car is and whether a van can reach it safely.
That is why we ask three questions before costing instead of after: what was put in, how much, and whether it's run. A range turns into a straight figure when the replies are in.
About Wellingborough, briefly
Wellingborough is a town in Northamptonshire, situated on the banks of the River Nene in the East Midlands region of England. Wellingborough has a population of approximately 28,148 people and is characterized by its predominantly terraced housing stock. Wellingborough sits at an elevation of 66 metres, about 60 miles north of London, and is close to nearby places such as Burrows Bush and Hatton Park. Wellingborough is also near the town of Irchester, with its smaller settlement of Little Irchester.
Across Northamptonshire and in Wellingborough: fuel drain cover
Burrows Bush, Hatton Park and Little Irchester are among the locations around Wellingborough that the same vans work, answering petrol in diesel jobs across Wellingborough's NN postcode area. You need not bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations where we work.
At the pump around Wellingborough, still?
Then you are in the best position there can be. Keep the car turned off, then ring.