Should You Worry? Petrol in a Diesel Car in Speke
Unstarted? Then less anxious than you likely are. "Have I ruined it?" is the first thing anyone around Speke asks, and the truthful answer is normally no, because petrol resting in a diesel tank hurts nothing till it's dragged through your fuel system — by ignition priming, by the starter, or by being driven. Keep it that way: leave the engine off and ring Petrol in Diesel. The remainder of this page covers what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
What petrol in a diesel does to the engine
Diesel has two jobs on its way through a motor. It lubricates first, and after that does it burn. What keeps the surfaces inside the high-pressure pump and the fuel injectors from wearing down against one another is the diesel flowing through them — they're built to very fine tolerances.
Of those two tasks, petrol handles the first badly and the second never. It is thinner than diesel and takes away the protection your fuel system rests on, and so a pump running on a petrol mixture 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 is where the clattering comes from.
Taken together, they show what shape the trouble takes. The damage is done by movement, not by contact. Petrol in a tank is a fuel issue. Whatever a worn pump sheds travels on, borne by the fuel, into the fuel injectors downstream, which is why a pump that has worked on the petrol is where a mechanical issue begins.
How serious is petrol in a diesel? Four situations our technicians see around Speke
Filled but never started — as good as it gets. Being on a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol kept inside the tank alone, it is cleared and flushed right where it stands, and nothing more is needed.
Ignition on, or started for a second. Once primed, your system has drawn petrol out of the tank as far as your filter and the lines. That's usually still a simple task — a drain, a flush, and your filter dealt with.
The pump has spent a couple of miles on weakened fuel — that's what driving the vehicle does. Distance is only half of that; how hard it was driven matters equally. Either way the work runs to the tank, the fuel lines, the filter and fresh fuel through the whole system. On the school run to Stockton Wood Community Primary School, the mileage is small. Any distance on the M62, under 5 miles from Speke, means the motor has worked hard throughout, and a run to Liverpool, under 10 miles away, is a very different task as well.
Clattering, a ragged idle, smoke, a throttle gone soft: driven until it complained. That is the engine telling you its fuel no longer is acting like diesel. Pull up wherever you are — the verge on Speke Church Road, a lay-by, a side street — and leave it there. Lasting damage is very rare when a car is pulled over early, and the drain and flush-through that still come first take care of it.
Myths Speke motorists hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A fuller tank of the same mix is all you get, since topping up removes nothing. The assumption behind the guidance — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." Protection matters more on modern diesels, not less, because their fuel passes through more precise components at higher pressure.
This is the one that fools people. Myth: "If it starts and drives, there's no damage done." Feed diesel to a petrol motor and it generally will not run, so the motorist stops — and the damage stops with them. A diesel fed petrol generally starts, ticks over and drives away as if nothing has happened, while the pump grinds. Running does not mean fine.
Myth: "Add some two-stroke oil and drive the car home." It is an outdated fix for a different fault. None of what petrol diluted is put back by it — and afterwards, your tank still contains that petrol.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol sits in your filter and lines, waiting to go straight back through your pump at your next start. On top of that, petrol cleared into a can by the road is genuinely hazardous.
Why petrol in a diesel takes place so easily
Nobody does it on purpose, and it's rarely carelessness. A diesel nozzle mostly won't fit a petrol vehicle, yet the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error simple, and just in one direction.
Habit and the vehicle falling out of step is how it occurs. A new motor, 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 train to catch, and a hurried fill en route to Hunts Cross. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Renault Clio for the first time. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of children.
Preventing petrol in a diesel next time you fill up in Speke
- Check the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, but not on each forecourt. The label is what counts.
- In a vehicle you don't know, look inside the flap over your filler or at the cap before your first fill: many vehicles state the fuel type there.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, in a home with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It sounds silly and it works.
- Mistakes like this are straightforward to make whilst your mind is on something else, and so your phone goes away.
- Some diesels have a filler designed to refuse 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.
- Stop as soon as you realise. Less petrol inside your tank means a weaker blend. It does not change what to do next, which is still not to start the car.
Already put petrol in a diesel around Speke?
Then the order of things is short. Never fire it up, and don't switch the ignition on. If you're still on the forecourt — EG On the Move or anywhere else — ask the attendants to help you roll the car away from the pump. Then phone 0333 366 0103 and tell us what went in, about how much, and if it has run.
Say so if it was AdBlue instead of petrol: it is a separate fault, with its own page for Speke, because AdBlue brings corrosion and deposits rather than lost lubrication.
Speke petrol in a diesel tasks: why one costs more than another
The four situations above are four separate tasks, so no single price for this would be fair. Mostly, your cost shifts with which one you are in. After that it is the proportion — how much petrol went in against how much your tank takes — and after that where the vehicle is and whether our van can get to it safely.
What got in, how much, and if it has run — three queries we ask before pricing, not after, for precisely that reason. A range turns into a straight figure when those answers are in.
About Speke and its setting
Speke is a suburban area in Merseyside, located on the coastal fringe of the Liverpool urban area, approximately 6.7 miles south of Liverpool city centre. Speke sits at a relatively low elevation of 26 metres, near the mouth of the River Mersey, and is bordered by nearby places such as Hunts Cross, Oglet, and Garston. Speke has a population of around 4419 people, predominantly living in terraced housing.
Fuel drain cover around Speke and across Merseyside
Speke sits in the L postcode area, and our teams that answer petrol in diesel jobs there work the places around it as well — Hunts Cross, Oglet and Garston among them. You need not bring your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots we drain.
In Speke and still at the petrol pump?
Then you are in the best spot there is. Keep the car switched off, and ring.