Petrol in a Diesel Car in Presdales: How Worried Should You Be?
Far less than you likely are, if it hasn't been started. Until your ignition primes your pump, your starter turns, or your car is driven, petrol in a diesel tank just waits there and does nothing. Which means the honest reply to the first Presdales query — "have I ruined it?" — usually no. Keep it that way: leave the motor off and ring Petrol in Diesel. The rest of this page sets out what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
Your engine and petrol in a diesel: what happens
Diesel has two tasks on its way through a motor. It lubricates first, and after that does it burn. The high-pressure pump and the injectors are designed to very fine clearances, and your diesel passing through them is what stops those surfaces from grinding against one another.
Petrol handles the first job badly and the second not at all. It's thinner than diesel and takes away the protection the system rests on, and so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That's where the clattering comes from.
The shape of the problem is plain once you put those together. Not contact but circulation is what does the damage. Any tank with petrol in it is a fuel fault. Whatever a worn pump sheds travels on, borne by the fuel, into your injectors downstream, which is why a pump that has worked on the petrol is where a mechanical issue begins.
Presdales, petrol in a diesel: four cases, from mild to major
Filled up, not once started. The best case there is. Being on a forecourt is what makes this the case: elsewhere, the vehicle has been driven there to begin with. With the petrol held inside your tank alone, it is drained and purged on the spot, and nothing more is needed.
A moment's running, or merely the ignition on. Petrol has left that tank and got to the fuel filter and the lines, since the fuel system has been bled. Drain, flush, see to your filter: still normally simple.
Those few miles driven meant your pump labouring on fuel diluted by petrol throughout. Tank, lines, filter, then clean fuel put through the entire system: that's this work, and the way the car was driven matters as much as the distance. Driving the kids to Christ Church CofE (VA) Primary School and Nursery is one sort of trip. Any mileage on the M11, under 10 miles from Presdales, means the motor working hard throughout, and a run to St Albans, under 15 miles away, is a very different task too.
Driven till it protested. Clattering, a lumpy idle, smoke, a throttle that has gone soft. The fuel is not behaving like diesel any more, and the motor is telling you. Stop on the spot — on the verge on Marsh Lane, at the kerb, down a side road — and don't move it. A vehicle pulled over early very rarely has permanent damage, since the drain and the flush, which still go first, take care of it.
Petrol in a diesel myths Presdales motorists hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Topping up takes out nothing; it gives you a bigger tank of the same mix. That guidance supposes a diesel fuel system handles petrol by percentage. It doesn't.
Myth: a modern diesel copes with a bit of petrol. Rather, the opposite. At higher pressure, through smaller components: that's how a newer diesel moves its fuel, and so the lubrication matters for more, not less.
One myth that catches people off guard: if it starts and drives, it must be unharmed. Diesel in a petrol motor generally leaves a motor that will not run: the motorist stops, and so does the harm. While your pump wears, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. Being able to run is not proof of being fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate issue. The petrol is still inside the tank afterwards, and what it has diluted is not put back.
The next start draws petrol back round your pump out of your lines and your filter, where some of that ends up after the motor has run. That's why draining your tank yourself doesn't leave you sorted — a myth. Clearing petrol into a can by the kerbside is also genuinely hazardous.
Why petrol in a diesel occurs at all
Carelessness is rarely the cause, and nobody means to do it. The forecourt makes it simple: the petrol nozzle is the slimmer of the two, and it slides 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.
It takes place when routine and your car stop matching. A new vehicle, a hire car or a courtesy car. Households running one of each, petrol and diesel. Your usual forecourt, its pumps suddenly in a different order. Fuelling up in a hurry en route to Ware, with a train to catch. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. With rain, a call arriving, or children to deal with, your hand simply does what it always has.
Presdales motorists: how to prevent petrol in a diesel next time
- The label is what counts, and so read the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- The first fill in a new motor is the time to check your filler flap — inside it, or on the cap, plenty of motors state which fuel to use.
- Good intentions count for less than a sticker or a fob in a bright colour on the diesel's key if a household has one of each. So label it.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Silly, yes, yet it does the trick.
- Put your phone away. This is an easy mistake to make while you are thinking about something else.
- Add-on devices are available for motors without one, and some diesels are built with a filler that will not take a petrol nozzle. Helpful — but a safety net at best, never a reason to stop checking the label.
- Less petrol makes a thinner mixture, so stop as soon as you notice — though remembering that the next stage is unchanged. It's still not to crank it.
Already put petrol in a diesel around Presdales?
Short and simple, then, is the order of things. Do not crank it, and do not turn the ignition on. Ask the attendants to help you push it clear of the petrol pump if you're still at the forecourt, whether that is Esso or anywhere else. Ring 0333 366 0103 next, with three facts — the fuel, the approximate quantity, and if it's run.
Corrosion and deposits are the issue with AdBlue, whereas petrol brings lost lubrication. So if it was AdBlue, say so — and read its own Presdales page.
What makes one Presdales petrol in a diesel job cost more than the next
Four separate tasks lie behind the four situations above — which is why there's no fair single quote. What moves your cost is mostly which of them you're in. Next it's the proportion — how much petrol went in against how much your tank holds — and then where your car is and whether our van can get to it safely.
That is why we ask three queries before costing rather than after: what was put in, how much, and whether it has run. A range becomes a straight figure when the answers are in.
About Presdales itself
Presdales is a locality situated on the lakeside in Hertfordshire, with an elevation of 33 metres. Presdales lies approximately 21 miles north of London and 14 miles southeast of St Albans, near the communities of Great Amwell, Ware, and Rush Green. Presdales is characterized by its predominant flat housing and a population of around 550 residents.
Fuel drain cover in Presdales and across Hertfordshire
Petrol in diesel call-outs in Presdales — part of the SG postcode area — go to teams that likewise cover the spots around it, Great Amwell, Ware and Rush Green among them. Our engineers drain where your car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Presdales: still at the petrol pump?
Nothing beats it: that is where you now are. Leave the vehicle switched off, then ring.