How Worried Should You Be? Petrol in a Diesel Car in Battlefield
Not started? Then less worried than you probably feel. "Have I ruined it?" is the first thing anyone around Battlefield asks, and the honest answer is generally no, since petrol left in a diesel tank harms nothing till it's dragged through your fuel system — by ignition priming, by the starter, or by being driven. Leave your motor off then phone Petrol in Diesel — that keeps it that way. What petrol really does to a diesel, how to gauge how far it has gone, and how to keep it from happening a second time: that's the rest of this page.
Petrol in a diesel: what does it do to the engine?
Two jobs fall to diesel on its journey round a motor. Lubricating comes before burning; it does both. The high-pressure pump and the fuel injectors are built to extremely fine gaps, and your diesel passing through them is what stops those surfaces from grinding against each other.
Badly at the first, not at all at the second: that's petrol. It's thinner than diesel and strips away the protection the fuel system depends 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 opposite of what a diesel needs from its fuel. That is where the rattling comes from.
Combined, those leave the shape of the problem clear. Contact does not do the harm — movement does. Petrol in a tank is a fuel problem. After your pump has been labouring on that petrol, a mechanical problem has started: anything shed by a pump that's grinding is carried onward to the injectors with your fuel.
How serious is petrol in a diesel? Four situations we see in Battlefield
Fuelled but never started — as good as it gets. Just the tank has petrol in it, so the task is draining that tank and purging the fuel system where the car stands. This situation can only really take place at a forecourt: anywhere else, the vehicle got there by being driven.
A moment's running, or just the ignition on. The fuel system has been primed, so petrol has left your tank and reached your filter and the lines. That's normally still a simple job — a drain, a flush, and your filter seen to.
Driven a few miles. Now your pump has spent these miles running on weakened fuel. Tank, lines, filter, then fresh fuel run through the whole circuit: that's this work, and the way the car was driven matters as much as the distance. On the school run to Greenacres Primary School, the mileage is short. Very different a second time: a run to Wrexham, under 25 miles away, or any mileage on the M54, under 10 miles from Battlefield, where the engine kept labouring hard.
Driven on until it protested — rattling, smoke, a ragged idle, a dead throttle. The fuel isn't acting like diesel any more, and your motor is saying so. Pull up wherever you are — the verge on Lion Coppice View, a lay-by, a side street — and leave the vehicle there. Long-term damage is very unusual when a vehicle is stopped soon, and the drain and flush-through that still come first sort it out.
Petrol in a diesel myths Battlefield people hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Topping up takes out nothing; it gives you a bigger tank of the same mixture. That advice assumes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. A newer diesel runs its fuel through more precise components at higher pressure, which makes the protection matter more, not less.
"It starts, it drives, and so there is no harm" — the myth that catches most motorists than any other. Diesel in a petrol motor generally means a motor that will not run: the motorist stops, and so does the damage. Feed petrol to a diesel and it usually starts, idles and pulls away like nothing has happened — all the while its pump is wearing. A running engine does not mean fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old fix, supposed for another issue. That petrol is still in that tank after that, and what it has weakened is not put back.
The next start sends petrol back round the pump from the lines and your filter, where some of it sits once your engine has been run. That's why draining the tank yourself does not leave you sorted — a myth. Also, a can of petrol filled at the roadside is truly hazardous.
How does petrol in a diesel take place?
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the narrower of the two and slides 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 simple, and the slip runs one way.
Routine and the car getting out of step is how it happens. Any car that's new to you — hired, on loan as a courtesy car, or brand new. One petrol and one diesel on the driveway of the same household. Your usual forecourt, its pumps now in a different order. A hurried fill on the way to Shrewsbury with a train to catch. Years of petrol vehicles behind you, a diesel Volkswagen Passat in front of you at the forecourt for its first tank — that's when. With rain, a call coming in, or a car full of children to deal with, the hand just does what it always has.
Next time you fill up around Battlefield: preventing petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most usually do. Check the pump's label; the colour is just a clue.
- Check the filler flap. Many cars state the fuel type inside the flap or on the cap. Look at it on the first fill in a vehicle you don't know.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key when a household has one of each. So mark it.
- Before the nozzle leaves the pump the first time you fuel a hired or new car, say "diesel" aloud. Daft, perhaps, but it does the trick.
- Put the phone away. This is an easy mistake to make while you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to refuse a petrol nozzle, and add-on devices exist for the remainder. Count it as a safety net, then keep reading the petrol pump.
- As soon as you realise, stop: less petrol inside that tank makes a thinner blend. What to do next doesn't change, though — still do not crank it.
Petrol already in a diesel around Battlefield? Begin here
Then the order of things is brief. Leave it unstarted, with the ignition switched off too. If you are still on the forecourt — BP or anywhere else — ask the attendants to help you roll the car clear of the petrol pump. What got in, about how much, and whether it's run: tell us that when you ring 0333 366 0103.
If it was AdBlue rather than petrol, say so. That's a separate problem — corrosion and deposits instead of lost lubrication — and it has its own page for Battlefield.
Why one petrol in a diesel job around Battlefield costs more than another
An honest single price does not exist here: four scenarios, four separate jobs. The situation itself does most of the work of moving the cost. The share counts next, meaning how much of your tank is petrol, followed by the position of the car and whether reaching it is safe for our van.
That is why our engineers ask three questions before quoting rather than after: what was put in, how much, and whether it's run. The replies turn a range into a straight figure.
About Battlefield itself
Battlefield is a suburban area in Shropshire, situated inland at an elevation of 73 metres, with detached housing being the predominant type of accommodation. Battlefield lies approximately 23.9 miles from Wrexham and is close to nearby places such as Upper Battlefield, Harlescott, and Sundorne. Battlefield has a population of around 1329 residents and is located about 139.3 miles from London.
Across Shropshire and around Battlefield: fuel drain cover
Upper Battlefield, Harlescott and Sundorne are among the places around Battlefield that the same teams work, answering petrol in diesel jobs across Battlefield's SY postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations our technicians work, and your car does not need to move to us.
Battlefield: still at the pump?
The best place there is, then — that is where you are. Keep it off. Call.