How Worried Should You Be? Petrol in a Diesel Car in Studlands Park
Unstarted? Then less anxious than you probably feel. Petrol resting in a diesel tank does nothing to your engine until something draws it through the fuel system — the ignition priming the pump, the starter, or the drive itself. So the honest answer to the first query everyone in Studlands Park asks, "have I wrecked it?", is usually no. Petrol in Diesel is who to phone, with the motor left off, so it remains that way. The rest of this page explains what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Inside the motor: what petrol in a diesel really does
On its way through a motor, diesel does two tasks. It combusts, and before it combusts it protects. Designed to very fine gaps, the fuel injectors and your pump rely on the diesel flowing through them to stop their surfaces wearing against one another.
Badly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump running on the blend wearing itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the knocking.
Put those together and the shape of the issue is plain. Contact does not do the damage — movement does. Where that petrol is only inside that tank, it is a problem of fuel, nothing more. The beginning of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Four situations we see in Studlands Park: how bad is petrol in a diesel?
The best case there can be: filled up, not once started. Only that tank has petrol in it, and so the job is emptying the tank and cleaning your system where your car stands. This situation can only truly happen at a forecourt: anywhere else, the car got there by being driven.
Ignition on, or started for a moment. With the system primed, your lines and filter now contain petrol that came from the tank. Usually nothing more than draining, purging and sorting the fuel filter, so still easy.
A couple of miles driven, and your pump has spent each of them labouring on diluted fuel. Tank, lines, filter, then clean fuel run through the entire system: that's the work, and the way the vehicle was driven matters as much as the distance. Short trips, such as the school run to Laureate Community Academy, are one thing. Any distance on the M11, under 15 miles from Studlands Park, means the motor working hard throughout, and a run to Ely, under 15 miles away, is a very different task too.
Driven until it protested. Clattering, an uneven idle, smoke, a throttle that has gone soft. That is the engine telling you its fuel no longer is behaving like diesel. Leave it where it stops: a lay-by, a side street, the verge on Aureole Walk. What goes first is still the drain and flush-through, and that takes care of it, with lasting damage very uncommon if a vehicle is stopped early.
Stories Studlands Park drivers hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing is removed by topping up — you are left with a fuller tank, still the same mix. Percentage isn't how a diesel fuel system copes with petrol, whatever that guidance presumes.
Not so: a newer diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through finer components: that's how a current diesel handles its fuel, so the lubrication counts more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that fools drivers. The motorist of a petrol motor fed diesel normally stops, because it will not run, and the harm stops with them. Feed petrol to a diesel and it usually starts, ticks over and drives away like nothing has happened — all the while its pump is wearing. Running does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different issue. That petrol is still in that tank after that, and what it has diluted is not put back.
"Drain it yourself and you are sorted" — a myth, since after it's been running some petrol sits in your filter and lines, ready to go straight back through your pump at the next start. And, a can of petrol filled at the roadside is truly dangerous.
How does petrol in a diesel occur?
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle generally won't fit a petrol vehicle, but the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and just in that direction.
The moment routine stops matching your car is the moment it takes place. Any motor that's new to you — a hire car, on loan as a courtesy car, or just bought. One petrol and one diesel on the drive of the same household. Your ordinary forecourt, its pumps suddenly in a different order. Rushing for a train at Newmarket and fuelling up en route. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: precisely when it takes place. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
How to avoid petrol in a diesel at your next fill-up in Studlands Park
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Read the petrol pump's label; the colour is only a clue.
- Plenty of cars state the fuel inside your filler flap or on the cap, so check there on the first fill in a vehicle you do not know.
- Good intentions do less than a sticker or a fob in a bright colour on your diesel's key if a home has one of each. So mark it.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump. It seems daft and it does the trick.
- Put the phone away. This is an easy mistake to make whilst you are thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler built to block a petrol nozzle, and add-on devices exist for cars without one. They are a backstop, not a reason to stop checking the pump.
- Less petrol makes a weaker mixture, so stop the moment you realise — though remembering that your next stage is unchanged. It is still not to crank it.
Already put petrol in a diesel in Studlands Park?
Then the order of things is short. Leave it unstarted, with your ignition switched off as well. If you're still on the forecourt — Tesco or anywhere else — ask the staff to help you push the car away from the pump. Next, 0333 366 0103. We will ask what got in, roughly how much, and if it's been run.
Corrosion and deposits form the trouble with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and see its own Studlands Park page.
One petrol in a diesel job around Studlands Park costs more than another. Why?
An honest single price does not exist here: four scenarios, four separate tasks. Which of them you're in is chiefly what moves your cost. The ratio matters next, meaning how much of that tank is petrol, and then the location of your car and whether getting to it is safe for a technician.
Before any quote, not after, we ask three queries: your fuel that was put in, its amount, and whether it's run. That is why. Those answers are what turn a range into one firm number.
About Studlands Park itself
Studlands Park is a suburban area in Suffolk, situated inland at an elevation of 29 metres, and is located near the cities of Ely and Newmarket. Studlands Park has a mix of housing types, but is predominantly characterised by terraced homes. Studlands Park is close to several nearby villages, including Exning, Snailwell, and Landwade, and is about 56.8 miles from London.
Studlands Park and Suffolk: where our fuel drain cover reaches
Studlands Park rests in the CB postcode area, and the teams that answer petrol in diesel calls there work the places near it as well — Exning, Snailwell and Landwade among them. The car does not need to come to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the pump around Studlands Park?
Then you are in the best spot there can be. Keep it off. Call.