How Worried Should You Be? Petrol in a Diesel Car in Leigh
If it hasn't been started, you can worry less than you probably are. Petrol sitting in a diesel tank does nothing to the motor till something draws it through the fuel system — your ignition priming the pump, your starter, or the drive on its own. So the fair answer to the first query anyone around Leigh asks, "have I wrecked it?", is normally no. Keep it that way: leave your engine off then call Petrol in Diesel. The rest of this page explains what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you again.
The motor and petrol in a diesel: what happens
Diesel has two tasks on its way through a motor. It protects first, and after that does it burn. Made to very fine gaps, the injectors and the pump depend on the diesel flowing through them to stop their surfaces wearing against one another.
The second job petrol does not do at all, and the first it does poorly. A pump working on a petrol blend is wearing itself out, because petrol is runnier than diesel and strips out the lubrication your fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that is where any clattering comes.
Combined, those make the shape of the problem clear. Not contact but circulation is what causes the damage. All a tank with petrol in it amounts to is a fuel fault. Whatever a worn pump sheds travels on, borne by your fuel, into the fuel injectors downstream, which is why a pump that has worked on the petrol is where a mechanical fault begins.
Petrol in a diesel in Leigh: how serious is it? Four situations
Filled up, not once started. The best case there can be. Just the tank has petrol in it, so the job is clearing that tank and rinsing the fuel system where the vehicle stands. This scenario can only really occur at a forecourt: anywhere else, your car got there by being driven.
A moment's running, or just your ignition on. Once primed, the system has pulled petrol out of that tank up to the fuel filter and your lines. Usually nothing more than clearing, cleaning and sorting the fuel filter, so still straightforward.
A couple of miles driven, and the pump has spent each of them labouring on thinned fuel. How hard your car was driven counts as much as how far, and this work covers your tank, the fuel lines, your filter and fresh fuel through the whole system. The school run to Leigh Primary School is one matter. Any distance on the M25, under 10 miles from Leigh, means the motor working hard throughout, and a run to London, under 50 miles away, makes a very different job as well.
Driven on till it complained — rattling, smoke, a ragged idle, a dead throttle. That's the engine telling you its fuel no longer is acting like diesel. Pull up wherever you are — the verge on Powder Mill Lane, a lay-by, a side street — then leave it where it is. The drain and flush still come first, and they sort it out: when a car is pulled over soon, permanent damage is very rare.
Leigh people and that petrol in a diesel stories they hear
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're left with a fuller tank, still the same mix. The assumption behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Modern diesels can handle a little petrol" — a myth, and nearer the opposite. Lubrication matters more on modern diesels, not less, because their fuel passes through finer parts at higher pressure.
Myth: "If it starts and drives, there is no harm done." This is the one that fools motorists. Any petrol motor fed diesel usually won't run, so the motorist stops and the harm stops with them. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, while the pump wears. Running is not the same as fine.
Myth: a two-stroke additive lets you to drive home. It is an old fix, meant for another issue. The petrol is still in your tank afterwards, and what it has diluted is not put back.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol lies in the fuel filter and lines, ready to go right back through the pump on the next start. Clearing petrol into a can by the kerbside is also truly dangerous.
How petrol ends up: petrol in a diesel
Carelessness is rarely the cause, and no one means to do it. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol motor at all. The forecourt makes it simple, and the error runs one way.
It takes place when routine and your car stop matching. Any car that is new to you — a hire car, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps laid out differently. Fuelling up in a rush on the way to Leigh (Kent), with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it occurs. Add rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Leigh motorists: how to prevent petrol in a diesel next time
- Green for unleaded and black for diesel is normal in the UK — but not on each forecourt. Go by the label on the petrol pump, not the colour.
- Inspect your filler flap. Plenty of cars state the fuel inside the flap or on the cap. Look at it on the first fill in a car you do not know.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a household with one of each.
- Before the nozzle comes off the petrol pump the first time you fill a hired or new motor, say "diesel" out loud. Silly, perhaps, yet it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away then keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop reading the petrol pump.
- The moment you notice, stop: less petrol inside that tank means a weaker mix. What to do next does not change, though — still don't crank it.
Put petrol in a diesel in Leigh already?
Short and simple, then, is the order of things. Never start the car, and don't switch the ignition on. The attendants at the forecourt — whether at BP itself or wherever you filled up — will usually help push it clear of the pump if you ask. Next, 0333 366 0103. We will ask what went in, about how much, and if it has been run.
If it was AdBlue and not petrol, say so. That is a separate problem — corrosion and deposits and not lost lubrication — and it has its own page for Leigh.
What makes one Leigh petrol in a diesel task cost more than the next
The four scenarios above are four different jobs, so no single price for this would be fair. What moves the cost is chiefly which of them you're in. Next it is the share — how much petrol was put in against how much the tank takes — and after that where the car is and whether a technician can reach it safely.
Ahead of any quote, not after, we ask three queries: the fuel that was put in, its volume, and whether it's run. That is why. With those replies, there is a straight figure instead of a range.
About Leigh itself
Leigh is a small village in Kent, situated inland at an elevation of around 35 metres, and is located approximately 26 miles from London. Leigh has a population of around 722 people and is characterised by predominantly detached housing. Leigh is near to other small settlements such as Stocks Green, Powder Mills, and Lower Haysden, and is part of the wider countryside of the South East region. Leigh sits in a rural area with nearby cities, including London, being within commuting distance.
Fuel drain cover across Kent, Leigh included
Petrol in diesel call-outs around Leigh — part of the TN postcode area — go to vans that likewise cover the spots round it, Stocks Green, Powder Mills and Lower Haysden among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians work, and your vehicle does not need to come to us.
Still at the pump in Leigh?
The best position there is, then — that's where you are. Leave it switched off, and ring.