How Worried Should You Be? Petrol in a Diesel Car in Greave
Less than you likely are, if it hasn't been started. Till the ignition primes the pump, the starter turns, or the car is driven, petrol in a diesel tank just waits there and does no harm. Which makes the truthful reply to that first Greave question — "have I ruined it?" — usually no. Petrol in Diesel is who to call, with the engine left off, and so it stays that way. What petrol actually does to a diesel, how to gauge how far it's gone, and how to stop it from happening a second time: that's the remainder of this page.
Your engine and petrol in a diesel: what goes on
Diesel has two jobs on its way through an engine. Oiling comes before burning; it does both. Your high-pressure pump and the injectors are built to very fine tolerances, and your diesel passing through them is what stops those surfaces from wearing against one another.
Badly at the first, not at all at the second: that's petrol. It is thinner than diesel and strips away the lubrication your fuel system hinges on, so a pump running on a petrol mix is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the rattling comes from.
The shape of the trouble is clear once you put those together. The harm is done by circulation, not by contact. Where the petrol is only inside the tank, it's a problem of fuel, nothing more. The beginning of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to the injectors downstream.
Four situations our technicians see around Greave: how bad is petrol in a diesel?
Filled up, and never started: no case is better. Being on a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With that petrol held inside the tank alone, it is drained and rinsed right where it stands, and nothing more is needed.
Started for a moment, or only the ignition on. Once primed, the system has drawn petrol out of the tank up to the fuel filter and your lines. Still usually easy: drain, flush, and your filter sorted.
Those few miles driven were your pump working on fuel weakened by petrol throughout. Miles is only half of it; how hard it was driven counts equally. Either way this work includes that tank, the lines, the fuel filter and clean fuel through the entire circuit. On the school run to Meanwood Community Nursery and Primary School, the distance is small. A run as far as Manchester, under 15 miles away, is a very different task. So is any distance on the A627(M), under 3 miles from Greave, where your engine has been labouring hard throughout.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone uneven. What you are hearing is the engine signalling fuel that no longer acts like diesel. Whether it's the verge on Parkway, a lay-by or a side street, stop where you are and leave it. Long-term damage is very rare if a car is pulled over quickly, and the fuel drain and flush-through that still come first sort it out.
Stories Greave people hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. A bigger tank of the same mix is all it gives, since topping up removes nothing. Percentage isn't how a diesel fuel system copes with petrol, whatever that advice assumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. At higher pressure, through more precise components: that's how a newer diesel moves its fuel, and so the lubrication counts more, not less.
One myth that catches drivers off guard: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel usually has no choice but to stop, because it will not run, and the harm stops with them. Whilst the pump wears, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. Running doesn't mean fine.
Myth: a two-stroke additive lets you to drive home. It is an old fix, supposed for another problem. None of what petrol diluted gets put back by it — and afterwards, the tank still contains the petrol.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol sits in the fuel filter and lines, ready to go right back through your pump on the next start. Clearing petrol into a can by the kerbside is also truly hazardous.
How petrol ends up: petrol in a diesel
A careless moment is rarely the cause, and no one means to do it. The forecourt makes it simple: the petrol nozzle is the slimmer of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle generally will not go into a petrol car at all. So the mistake runs one way.
The moment routine stops matching the vehicle is the moment it happens. Courtesy car, hire car, or a car that's new. Two motors on one driveway, one petrol, one diesel. A well-known forecourt with the pumps in a different order. A train to catch, and a hurried fill en route to Rochdale. A new-to-you diesel Renault Megane, its first fuelling, and a driver accustomed to petrol: exactly when it happens. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel at your next fill-up in Greave
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Read the petrol pump's label; the colour is only a clue.
- In a vehicle you don't know, look inside the flap over the filler or at the cap before the first fill: many motors print the fuel type there.
- Good intentions do 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 lift the nozzle — each time a new or hired car needs its first tank. It seems daft. It works.
- Thinking about something else is when this becomes an easy mistake to make, so tuck the phone away and keep your mind on the petrol pump.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Less petrol means a thinner mixture, so stop the moment you realise — though remembering that the next step is unchanged. It is still not to fire it up.
Petrol already in a diesel around Greave? Start here
The order of things is short, then. Do not switch the ignition on, and don't fire it up. If you're still on the forecourt — Texaco or anywhere else — ask the staff to help you roll it away from the pump. Next, 0333 366 0103. We'll ask what went in, roughly how much, and if it's been run.
Corrosion and deposits are the trouble with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and see its own Greave page.
Why one petrol in a diesel task in Greave costs more than another
The four scenarios above are four different tasks, so no single quote for this would be fair. Which of them you are in is chiefly what moves the cost. Two things follow that: the petrol that got in as a proportion of what that tank holds, then the place your car is in and whether a technician can reach it safely.
Three questions come first, before any quote, rather than after — what went in, how much, has it run — and this is the reason. A range becomes a straight figure once the replies are in.
About Greave itself
Greave is a suburban area in Greater Manchester, situated on the riverside at an elevation of 146 metres, with semi-detached housing being the predominant type of accommodation. Greave lies approximately 10 miles from Manchester and 169.5 miles from London, making it a commuter-friendly location. Greave is surrounded by nearby places such as Passmonds, Spotland Bridge, and Broadhalgh, and has a population of around 5312 residents.
Across Greater Manchester and in Greave: fuel drain cover
Our vans answering petrol in diesel calls in Greave, in the OL postcode area, also work the locations near it, Passmonds, Spotland Bridge and Broadhalgh among them. You need not move the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
In Greave and still at the pump?
No position is better: that is where you are. Turned off it remains; then ring.