Should You Worry? Petrol in a Diesel Car in Hillside
Less than you likely are, provided it hasn't been started. Till the ignition primes the pump, your starter turns, or your vehicle is driven, petrol in a diesel tank just sits there and does nothing. Which means the truthful reply to the first Hillside query — "have I wrecked it?" — usually no. Keep it that way: leave your engine off and phone Petrol in Diesel. Below, this page sets out 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
On its way through an engine, diesel has two tasks. It burns, and before it burns it protects. Your high-pressure pump and the injectors are made to extremely fine tolerances, and the diesel passing through them is what stops those surfaces from wearing down against one another.
Petrol does the first task badly and the second not at all. It is thinner than diesel and strips away the lubrication your fuel system rests on, and 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.
Seen together, they make clear the shape the trouble has. Not contact but movement is what does the damage. All a tank with petrol in it amounts to is a fuel fault. Whatever a worn pump sheds goes on, carried by the fuel, into the injectors downstream, which is why a pump that has been working on that petrol is where a mechanical problem begins.
How serious is petrol in a diesel? Four scenarios our technicians see in Hillside
Filled up, not once started. The best case there can be. At a forecourt, and really only there, the petrol is still confined to that tank — since everywhere else the vehicle was driven to reach it. The task is emptying and flushing on the spot.
Ignition on, or started for a second. Petrol has come out of the tank and reached your filter and the lines, because the fuel system has been bled. That is usually still a straightforward task — a drain, a flush, and your filter dealt with.
Your pump has worked a couple of miles on diluted fuel — that is what driving it does. How hard the car was driven counts as much as how far, and this work takes in your tank, your lines, the filter and clean fuel through the whole circuit. Short trips, such as the school run to the local primary school, are one thing. A run as far as Glasgow, under 10 miles away, is a very different job. So is any distance on the M77, under 3 miles from Hillside, where the motor has been working hard the whole time.
Driven on until it complained — rattling, smoke, an uneven idle, a soft throttle. The fuel isn't acting like diesel any more, and your motor is telling you. Whether it's the verge on Hillside Grove, a lay-by or a side road, stop where you are and leave it. The fuel drain and flush-through still come first, and they sort it out: if a car is stopped quickly, permanent damage is very rare.
Myths Hillside drivers hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mix. Percentage is not how a diesel fuel system copes with petrol, however much that guidance assumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. More precise components and higher pressure are how a modern diesel runs its fuel, and that makes the lubrication matter more, not less.
"It starts, it drives, so there is no harm" — the myth that catches more people than any other. Feed diesel to a petrol engine and it normally won't run, and so the driver stops — and the harm stops with them. Feed petrol to a diesel and it generally starts, idles and drives away like nothing has happened — all while its pump wears. Being able to run isn't proof of being fine.
Myth: "Add some two-stroke oil and drive the car home." It is an outdated workaround for a distinct problem. It does not put back what petrol has weakened, and that petrol is still in the tank afterwards.
Once the motor has run, part of that petrol sits in the fuel filter and the fuel lines, not that tank — and your next start pulls it right back through your pump. So the myth "drain your tank yourself and you're sorted" does not hold. Also, a can of petrol filled at the kerbside is genuinely risky.
Why petrol in a diesel takes place so easily
On purpose? Never. Through carelessness? Seldom, if ever. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol car at all. The forecourt makes it easy, and the slip runs one way.
When routine and your car stop matching, it happens. A new car, a hire car or a courtesy car. One petrol and one diesel on the drive of the same household. A well-known forecourt with the pumps in a different order. A rushed fill en route to Barrhead with a train to catch. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Renault Clio for the first time. With rain, a call coming in, or a car full of children to deal with, the hand just does what it has always done.
How to avoid petrol in a diesel at your next fill-up in Hillside
- The label is what matters, and so read the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- In a motor you do not know, look inside the flap over your filler or at the cap before your first fill: plenty of vehicles state the fuel type there.
- Good intentions count for less than a sticker or a fob in a vivid colour on the diesel's key when a household has one of each. So label it.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It sounds silly and it works.
- While you're thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Add-on devices are available for cars without one, and some diesels come with a filler that will not take a petrol nozzle. Useful — but a safety net at best, never a reason to stop checking the label.
- Stop the moment you notice. Less petrol in the tank makes a thinner mixture. It doesn't change what to do next, which is still not to start the vehicle.
Put petrol in a diesel in Hillside already?
In that case, there's only a short order of things. Do not switch your ignition on, and don't crank it. The staff at the forecourt — whether at Asda itself or wherever you filled up — will usually help push it away from the pump if you ask. Next, 0333 366 0103. We'll ask what was put in, roughly how much, and if it has been run.
Say so if it was AdBlue instead of petrol: it's a different issue, with its own page for Hillside, because AdBlue brings corrosion and deposits rather than lost protection.
What makes one Hillside petrol in a diesel task cost more than the next
An honest single price doesn't exist here: four scenarios, four separate jobs. What shifts your cost is chiefly which of them you are in. The ratio counts next, meaning how much of your tank is petrol, and then the position of your car and whether reaching it is safe for a technician.
What was put in, how much, and whether it has run — three queries our engineers ask before pricing, not after, for precisely that reason. Their answers are what change a range into one firm number.
About Hillside
Hillside is a suburban area situated on the shores of a lake in East Renfrewshire, with a mix of flat housing and local amenities. Hillside sits at an elevation of 112 metres, close to the nearby communities of Levernside and West Arthurlie. Hillside is located near Lochlibo and is approximately 8 miles from Glasgow, making it a commuter base for the city. Hillside has a population of around 1784 residents.
Across East Renfrewshire and in Hillside: fuel drain cover
Hillside waits in the G postcode area, and our teams that answer petrol in diesel call-outs there work the spots near it as well — Levernside, West Arthurlie and Lochlibo among them. No need to move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places where we work.
Still at the petrol pump in Hillside?
The best place there is, then — that is where you are. Switched off it stays; then phone.