Soughton: Petrol in a Diesel Car? How Worried to Be
Probably less than you already are — as long as nobody has started it. Everyone around Soughton begins with "have I ruined it?", and the honest answer is generally no: petrol left inside your tank of any diesel stays harmless till priming, cranking or driving draws it into the system. To leave the vehicle like that, ring Petrol in Diesel and leave the engine switched off. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to stop it from happening a second time: that's the rest of this page.
Inside the motor: what petrol in a diesel does
Diesel does two tasks on its way through a motor. Lubricating comes before burning; it does both. The high-pressure pump and your injectors are made to extremely fine tolerances, and your diesel passing through them is what keeps those surfaces from wearing against one another.
The second job petrol doesn't do at all, and the first it does poorly. The rattling comes from petrol being made not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the lubrication your system hinges on, and any pump running on that mixture is wearing itself.
Put these together and the shape of the trouble is plain. Not contact but circulation is what does the damage. Where the petrol is only in that tank, it is a problem of fuel, nothing more. Whatever a worn pump sheds travels on, borne by the fuel, into the fuel injectors downstream, which is why a pump that has been working on that petrol is where a mechanical issue starts.
Four scenarios our engineers see around Soughton: how serious is petrol in a diesel?
Fuelled but never started — as good as it gets. On a forecourt, and really only there, the petrol is still limited to that tank — because everywhere else the vehicle was driven to get to it. The task is draining and rinsing on the spot.
Ignition on, or started for a second. Petrol has left your tank and got to the filter and your lines, since the system has been bled. Normally nothing more than clearing, flushing and sorting the filter, and so still easy.
A couple of miles driven, and the pump has spent every one of them running on thinned fuel. The work is the tank, your lines, the fuel filter and clean fuel through the entire system, and how hard your car was driven counts as much as how far. Driving the kids to the local primary school is one sort of trip. A run as far as Chester, under 15 miles away, is a very different task. So is any miles on the M56, under 10 miles from Soughton, where the motor has been running hard the whole time.
It protested, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone ragged. That is your motor telling you its fuel no longer is behaving like diesel. Whether it is the verge on Ffordd Llundain, a lay-by or a side street, stop where you are then leave it. A car pulled over soon very rarely has long-term damage, because the drain and the flush, which still come first, take care of it.
What Soughton motorists get told about petrol in a diesel — and the myths in it
"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 mixture is all you get, because topping up takes out nothing. The idea behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Not so: a modern diesel copes with a bit of petrol. Rather, the opposite. At higher pressure, through more precise parts: that is how a current diesel moves its fuel, so the lubrication matters more, not less.
One myth that catches people off guard: if it starts and drives, it must be unharmed. Any petrol motor fed diesel normally won't run, and so the motorist stops and the harm stops with them. A diesel fed petrol normally starts, ticks over and drives away as if nothing has happened, whilst your pump grinds. Being able to run is not proof of being fine.
Myth: "Add some two-stroke oil and drive it home." It is an outdated workaround for a separate fault. What petrol has thinned remains weakened, and that petrol remains in that tank anyway.
Once the engine has run, part of the petrol sits in the filter and the fuel lines, not the tank — and the next start pulls it straight back through the pump. So the myth "drain the tank yourself and you are sorted" does not hold. Draining petrol into a can at the kerbside is also truly dangerous.
How petrol ends up: petrol in a diesel
No one does it on purpose, and it is seldom carelessness. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol vehicle at all. The forecourt makes it simple, and the error runs one way.
The moment habit stops matching the vehicle is the moment it occurs. Hire cars, courtesy cars, and motors that are new to you. Two motors on one driveway, one petrol, one diesel. Your ordinary forecourt, its pumps now in a different order. A train to catch, and a hurried fill en route to Buckley. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. Add a back seat full of kids, a phone call or rain, and the hand wins.
Soughton drivers: how to prevent petrol in a diesel next time
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Read the petrol pump's label; the colour is only a hint.
- 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 any car you don't know.
- Mark the key. In a home with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- Before the nozzle leaves the pump the first time you fuel a hired or new motor, say "diesel" aloud. Daft, yes, but it works.
- Mistakes like this are simple to make while your mind is on something else, and so your phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to refuse a petrol nozzle, and aftermarket devices are available for the rest. Count it as a safety net, and keep checking the petrol pump.
- Stop as soon as you realise. Less petrol in your tank means a thinner mix. It does not change what to do next, which is still not to start the car.
Petrol already in a diesel around Soughton? Begin here
Then the order of things is brief. Leave it unstarted, with your ignition off as well. The attendants on the forecourt — whether at Shell itself or wherever you filled up — will usually help roll it clear of the petrol pump if you ask. Ring 0333 366 0103 next, with three answers — the fuel, the approximate volume, and whether it's run.
Say so if it was AdBlue instead of petrol: it's a separate issue, with its own page for Soughton, since AdBlue brings corrosion and deposits instead of lost lubrication.
What makes one Soughton petrol in a diesel job cost more than the next
A fair single quote does not exist here: four scenarios, four separate tasks. Which of them you are in is chiefly what moves your cost. Two things follow that: the petrol that went in as a proportion of what the tank takes, then the place your car is in and whether a technician can get to it safely.
That's why we ask three questions before quoting rather than after: what went in, how much, and if it's run. Those replies turn a range into a straight figure.
About Soughton, briefly
Soughton is a village in Flintshire, situated inland at an elevation of 143 metres, approximately 10 miles from Chester. Soughton has a population of around 1697 people, with predominantly detached housing. Soughton is located near other small places such as New Brighton, Leadmill, and Maes-y-Dre, in a region of Wales with a mix of rural and urban landscapes.
Soughton and Flintshire: where our fuel drain cover runs
Petrol in diesel calls around Soughton — part of the CH postcode area — go to vans that also cover the spots round it, New Brighton, Leadmill and Maes-y-Dre among them. Our engineers drain wherever the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Still at the pump in Soughton?
Then, you could not be in a better place. Leave it turned off, and ring.