Petrol in a Diesel Car in Downton: How Worried Should You Be?
Probably less than you already are — provided no one has started the car. Petrol sitting in a diesel tank does nothing to your motor until something pulls it through the fuel system — your ignition priming your pump, your starter, or the drive on its own. So the honest answer to the first query everyone in Downton asks, "have I ruined it?", is usually no. Keep it like that: leave the engine off and call Petrol in Diesel. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and the way to make sure you never repeat it.
Inside your engine: what petrol in a diesel does
On its way through an engine, diesel does two tasks. It protects to begin with, and after that does it burn. Made to extremely fine clearances, the injectors and the pump rely on your diesel flowing through them to stop their surfaces wearing against one another.
Poorly at the first, not at all at the second: that's petrol. It's thinner than diesel and takes away the protection the fuel system rests 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 opposite of what a diesel needs from its fuel. That is where the rattling comes from.
The shape of the issue is clear when you put those together. The damage is done by movement, not by contact. Where the petrol is only inside the tank, it is a problem of fuel, nothing more. The start of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with the fuel to the fuel injectors beyond it.
Petrol in a diesel in Downton: how bad is it? Four situations
The best case there is: filled up, never started. Only that tank has petrol in it, so the task is draining the tank and cleaning the system where the car sits. This situation can only truly happen on a forecourt: anywhere else, the vehicle got there by being driven.
Started for a moment, or only the ignition on. With the fuel system primed, your lines and filter now contain petrol that came from your tank. That's normally still a simple task — a drain, a flush, and the fuel filter seen to.
Those few miles driven meant your pump labouring on fuel diluted by petrol the whole way. How hard the vehicle was driven counts as much as how far, and the work covers the tank, your lines, your filter and fresh fuel through the entire circuit. Driving the children to Downton CofE VA Primary School is one sort of trip. A run as far as Salisbury, under 10 miles away, is a very different task. So is any miles on the M27, under 10 miles from Downton, where the engine has been running hard the whole time.
Driven on until it complained — knocking, smoke, a ragged idle, a dead throttle. That is the motor telling you its fuel no longer is behaving like diesel. Stop wherever you are — the verge on High Street, a lay-by, a side street — then leave it where it is. The drain and flush still come first, and they deal with it: when a vehicle is stopped soon, lasting damage is very rare.
Petrol in a diesel stories Downton motorists hear
False: topping up to full with diesel makes it fine. It does not. Nothing comes out when you top up — that tank simply carries more of the same mixture. That advice presumes a diesel fuel system tolerates petrol by percentage. It does not.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." A current diesel sends its fuel through smaller components at higher pressure, which makes the protection matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no damage done." Feed diesel to a petrol engine and it generally will not run, and so the driver stops — and the harm stops with them. Feed petrol to a diesel and it generally fires up, idles and pulls away as if nothing happened — all the while its pump wears. Being able to run isn't the same as 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 in that tank after that, and whatever it has diluted isn't put back.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol sits in the fuel filter and lines, waiting to go right back through your pump at your next start. It's also really dangerous to drain petrol into a can by the kerbside.
How petrol ends up: petrol in a diesel
It's rarely carelessness, and no one does it on purpose. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally won't go into a petrol vehicle at all. The forecourt makes it simple, and the mistake runs one way.
When routine and the car stop matching, it takes place. A new car, a hire car or a courtesy car. Two vehicles on one driveway, one petrol, one diesel. Your ordinary forecourt, its pumps now in a different order. A train to catch, and a rushed fill en route to Dean. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Nissan Qashqai for the first time. With rain, a call coming in, or a car full of children to deal with, your hand simply does what it has always done.
Avoiding petrol in a diesel next time you fill up in Downton
- Green for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Go by the label on the pump, not the colour.
- Many motors state the fuel type inside your filler flap or on the cap, so check there on the first fill in a vehicle you don't know.
- Good intentions count for less than a sticker or a fob in a bright colour on your diesel's key when a home has one of each. So mark it.
- "Diesel", out loud, before you pick up the nozzle — every time a new or hired car gets its first tank. It sounds daft. It works.
- Mistakes like this are simple to make whilst your mind is on something else, and so the phone goes away.
- Add-on devices are available for vehicles without one, and some diesels are built with a filler that will not take a petrol nozzle. Useful — but a backstop only, never a reason to stop checking the label.
- Stop the moment you realise. Less petrol in the tank means a thinner mix. It does not change what to do next, which is still not to crank it.
Put petrol in a diesel in Downton already?
Then the order of things is brief. Starting it is out, and so is turning on the ignition. Still at the forecourt, at Esso or anywhere else? Ask the staff to help you roll the car clear of the petrol pump. Then phone 0333 366 0103 and tell us what got in, roughly how much, and whether it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a separate fault — Downton has a page all for it.
Downton petrol in a diesel jobs: why one costs more than another
There's no fair single price for this, because the four scenarios above are four different tasks. Which of them you're in is chiefly what moves the cost. The proportion counts next, meaning how much of the tank is petrol, and then the position of the vehicle and whether reaching it is safe for a technician.
What got in, how much, and if it's run — three questions our engineers ask before pricing, not after, for precisely that reason. Those answers change a range into a straight figure.
About Downton, briefly
Downton is a village in Wiltshire, situated on the banks of the River Avon at an elevation of around 44 metres. Downton lies near the city of Salisbury, with which it has strong transport links, and is also close to smaller settlements like Wick and Morgans Vale. Downton has a population of approximately 888 residents, who mostly live in semi-detached housing. Downton is located about 78 miles west of London, making it a relatively accessible rural community.
Across Wiltshire and around Downton: fuel drain cover
Our teams answering petrol in diesel calls in Downton, in the SP postcode area, also work the places near it, Wick, Morgans Vale and Redlynch included. A forecourt, a supermarket car park, a lay-by or your own drive are all spots our technicians drain, and the car doesn't need to come to us.
At the petrol pump in Downton, still?
Then you're in the best position there is. Keep it off. Phone.