Should You Worry? Petrol in a Diesel Car in Shinfield
Less than you likely are, provided it hasn't been started. Everyone in Shinfield begins with "have I wrecked it?", and the honest answer is normally no: petrol left in your tank of any diesel remains harmless until priming, cranking or driving draws it into the system. To keep the vehicle like that, call Petrol in Diesel then leave your engine switched off. What petrol actually does to a diesel, how to judge how far it's gone, and how to keep it from happening a second time: that is the remainder of this page.
The motor and petrol in a diesel: what happens
Diesel has two tasks on its way through a motor. It combusts, and before it ignites it lubricates. What stops the surfaces inside your high-pressure pump and the injectors from wearing against each other is the diesel passing through them — they are designed to extremely fine clearances.
Of these two tasks, petrol handles the first poorly and the second never. The clattering comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the lubrication the system hinges on, and any pump running on such a mix is wearing itself.
Taken together, they show what shape the issue takes. Contact does not do the damage — movement does. Petrol in the tank is a fuel issue. Whatever a worn pump sheds goes on, borne by your fuel, into your injectors downstream, which is why a pump that has been working on the petrol is where a mechanical fault starts.
How bad is petrol in a diesel? Four situations we see around Shinfield
The best case there can be: filled up, never started. Only your tank has petrol in it, and so the job is draining that tank and flushing the fuel system where the car sits. This scenario can only really occur at a forecourt: anywhere else, the car got there by being driven.
The ignition turned on, or a short start. With the system primed, the fuel lines and filter now hold petrol that came from that tank. Usually nothing more than clearing, cleaning and seeing to your filter, and so still easy.
Some miles driven, and your pump has spent every one of them working on weakened fuel. The work is the tank, your lines, the fuel filter and clean fuel through the whole circuit, and how hard your car was driven matters as much as how far. The school run to Shinfield Infant and Nursery School is one matter. Any miles on the M4, under a mile from Shinfield, means the motor has worked hard throughout, and a run to Oxford, under 50 miles away, is a very different job too.
Driven till it complained. Clattering, a lumpy idle, smoke, a throttle that has gone soft. The fuel is not acting like diesel any more, and the motor is telling you. Pull up wherever you are — the verge on Arborfield Road, a lay-by, a side street — and leave the vehicle where it is. A car stopped soon very rarely has long-term damage, because the drain and the flush, which still go first, deal with it.
What Shinfield motorists get told about petrol in a diesel — and the stories in it
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. That advice assumes a diesel fuel system tolerates petrol by percentage. It doesn't.
"Current diesels can handle a little petrol" — a myth, and nearer the reverse. A current diesel sends its fuel through smaller parts at higher pressure, which makes the protection count more, not less.
"It starts, it drives, and so there is no harm" — the myth that trips up more people than any other. Diesel in a petrol motor usually leaves a motor that won't run: the motorist stops, and so does the damage. Whilst the pump grinds, a diesel fed petrol usually starts, idles and drives away as though nothing has happened. 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. It does not put back what petrol has thinned, and that petrol is still inside your tank afterwards.
The next start draws petrol back round your pump out of the lines and the fuel filter, where some of it ends up once your engine has been run. That's why a DIY tank drain doesn't leave you sorted — a myth. And, a can of petrol filled by the roadside is genuinely risky.
Why petrol in a diesel takes place at all
No one does it on purpose, and it is seldom carelessness. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle mostly won't go into a petrol car at all. So the error runs one way.
Habit and the car falling out of step is how it happens. Hire cars, courtesy cars, and motors that are new to you. One petrol and one diesel on the driveway of the same household. Your ordinary forecourt, its pumps suddenly in a different order. A train to catch, and a rushed fill on the way to Earley. Exactly the moment it happens: after years of driving petrol, someone fills a diesel Volkswagen Golf 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.
Shinfield people: how to avoid petrol in a diesel next time
- The label is what matters, so read the petrol pump instead of the colour: in the UK unleaded handles are normally green and diesel black, yet not on every forecourt.
- In a motor you do not know, look inside the flap over your filler or at the cap before the first fill: many cars state the fuel there.
- Mark your key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It seems silly and 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.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built 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.
- The moment you realise, stop: less petrol in the tank makes a thinner blend. What to do next doesn't change, though — still do not crank it.
Petrol already in a diesel in Shinfield? Begin here
Then the order of things is short. Leave it unstarted, with the ignition switched off too. The attendants on the forecourt — whether at Esso itself or wherever you filled up — will normally help roll it clear of the petrol pump if you ask. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it has been run.
Say so if it was AdBlue rather than petrol: it's a separate fault, with its own page for Shinfield, because AdBlue brings corrosion and deposits rather than lost lubrication.
Why one petrol in a diesel task in Shinfield costs more than another
The four scenarios above are four different tasks, so no single price for this would be honest. The scenario itself does most of the work of moving your cost. Two things come after that: the petrol that went in as a share of what that tank takes, then the spot the car is in and whether a technician can reach it safely.
Before any quote, not after, we ask three queries: your fuel that got in, the volume, and if it's run. That is why. Given those replies, there is a straight figure instead of a range.
About Shinfield, briefly
Shinfield is a village in Berkshire, situated on the banks of the River Loddon at an elevation of around 47 metres. Shinfield lies within the South East region, approximately 35.9 miles from London and 27.4 miles from Oxford. Shinfield has a mix of housing types, with semi-detached homes being predominant, and is surrounded by nearby places such as Schoolgreen, Ryeish Green, and Whitley Wood.
Fuel drain cover around Shinfield and across Berkshire
Shinfield waits in the RG postcode area, and our teams that answer petrol in diesel calls there work the locations around it as well — Schoolgreen, Ryeish Green and Whitley Wood among them. You need not move your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
Still at the petrol pump around Shinfield?
Then you're in the best position there can be. Ring, and leave it turned off.