How Worried Should You Be? Petrol in a Diesel Car in Wick
Likely less than you already are — provided no one has started the car. "Have I wrecked it?" is the first question anyone in Wick asks, and the honest answer is normally no, because petrol left in a diesel tank hurts nothing until it is drawn through the fuel system — by ignition priming, by your starter, or by being driven. To keep the car that way, ring Petrol in Diesel and leave the motor alone. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and the way to make sure you never repeat it.
Petrol in a diesel: what does it do to the motor?
Passing through a motor, diesel is doing two jobs at once. It lubricates first, and only then does it burn. Your high-pressure pump and the injectors are made to very fine gaps, and the diesel passing through them is what keeps those surfaces from wearing against each other.
Badly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump on the mixture wearing itself. It's equally made to resist igniting under compression — the opposite of what a diesel needs — which is why you hear the knocking.
Combined, those make the shape of the problem plain. Not contact but circulation is what causes the harm. Where the petrol is only in that tank, it's an issue of fuel, nothing more. The start of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with the fuel to the fuel injectors downstream.
How bad is petrol in a diesel? Four scenarios our engineers see around Wick
The best case there can be: filled up, never started. Being on a forecourt is what makes this the case: elsewhere, your car has been driven there to begin with. With the petrol held inside the tank alone, it's cleared and rinsed right where it stands, and nothing more is needed.
Ignition on, or started for a second. With the fuel system primed, your lines and filter already hold petrol that has come from that tank. That's usually still a straightforward task — a drain, a flush, and the filter dealt with.
The pump has worked a few miles on diluted fuel — that is what driving it meant. The work is your tank, the lines, the fuel filter and clean fuel through the entire system, and how hard your car was driven matters as much as how far. The school run to Wick Church of England Primary School is one thing. Very different again: a trip to Bath, under 10 miles away, or some mileage on the M4, under 5 miles from Wick, where the motor never stopped working hard.
Driven until it protested. Knocking, a lumpy idle, smoke, a throttle that has gone soft. What you are hearing is your motor signalling fuel that no longer acts like diesel. Whether it's the verge on Golden Valley Road, a lay-by or a side street, stop there then leave it. What comes first is still the fuel drain and flush, and that takes care of it, with permanent damage very rare when a car is stopped soon.
Wick motorists and that petrol in a diesel stories they hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up removes nothing; it gives you a bigger tank of the same mixture. The idea behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A modern diesel can cope with a bit of petrol." Lubrication matters more on current diesels, not less, because their fuel passes through smaller parts at higher pressure.
The myth that catches motorists out: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it usually won't run, and so the driver stops — and the harm stops with them. A diesel fed petrol usually starts, ticks over and drives away as if nothing has happened, while the pump wears. Running isn't the same as fine.
An old workaround for a different issue is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol diluted is put back by it — and later, the tank still contains the petrol.
Myth: "Drain that tank yourself and you are sorted." After your engine has been run, some of that petrol is no longer inside your tank: it's in your filter and your lines, and it goes right back through your pump on the next start. Also, a can of petrol drained by the roadside is genuinely risky.
How petrol ends up: petrol in a diesel
It is rarely carelessness, and no one does it on purpose. One way only, since of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one mostly will not fit a petrol car. That is how the forecourt makes it straightforward.
When routine and your car stop matching, it happens. Courtesy car, hire car, or a vehicle that's brand new. Households running one of each, petrol and diesel. The pumps in a different order on a familiar forecourt. Fuelling up in a rush on the way to Keynsham, with a train to catch. Precisely the moment it occurs: after years of driving petrol, someone fills a diesel Volkswagen Tiguan for the first time. Your hand does what it has always done when you add rain, a phone call or a back seat full of children.
Avoiding petrol in a diesel next time you fill up around Wick
- A green handle for unleaded and black for diesel is normal in the UK — but not on every forecourt. Go by the label on the pump, not the colour.
- In a car you don't know, look inside the flap over the filler or at the cap before the first fill: many cars print the fuel type there.
- Good intentions do less than a sticker or a fob in a bright colour on your diesel's key if a household has one of each. So label it.
- "Diesel", aloud, before you lift the nozzle — every time a new or hired car needs its first tank. It seems daft. It does the trick.
- Put the phone away. This is an easy mistake to make while you are thinking about something else.
- Add-on devices are available for motors without one, and some diesels are built with a filler that will not accept a petrol nozzle. Helpful — but a backstop only, never a reason to stop checking the label.
- Spotting it mid-fill? Stop there and then. A thinner blend results from less petrol inside your tank, but your next step remains the same: don't fire it up.
Petrol already in a diesel around Wick? Begin here
Short and simple, then, is the order of things. Leave it unstarted, with the ignition off too. Still on the forecourt, at BP or anywhere else? Ask the attendants to help you roll it clear of the pump. Phone 0333 366 0103 next, with three facts — the fuel, the rough amount, and whether it's run.
Corrosion and deposits are the issue with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and see its own Wick page.
One petrol in a diesel task around Wick costs more than another. Why?
The four situations above are four different jobs, so no single quote for this would be honest. Which of them you are in is mostly what moves your cost. Two things come after that: the petrol that was put in as a share of what that tank holds, then the spot the car is in and whether a technician can reach it safely.
Ahead of any quote, not after, we ask three queries: your fuel that was put in, the quantity, and if it has run. That is why. With those answers, you get a straight figure instead of a range.
About Wick and where it is
Wick is a village in Gloucestershire, situated on the riverside at an elevation of around 50 metres, with nearby landmarks including Wick Rocks and Holbrook Common. Wick lies close to the city of Bath, approximately 5.8 miles away, and is part of the wider South West region. Wick has a population of around 889 people, predominantly living in semi-detached housing. Wick is also near Bridgeyate, another local community.
Wick and Gloucestershire: where our fuel drain cover runs
The teams answering petrol in diesel call-outs around Wick, in the BS postcode area, equally work the places near it, Wick Rocks, Holbrook Common and Bridgeyate among them. We drain where your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the petrol pump in Wick?
Then you're in the best spot there can be. Keep it off. Ring.