Should You Worry? Petrol in a Diesel Car in New Southgate
Far less than you likely are, provided it hasn't been started. Petrol sitting in a diesel tank does nothing to the engine till something pulls it through the fuel system — the ignition priming the pump, your starter, or the drive on its own. So the honest answer to the first query everyone in New Southgate asks, "have I wrecked it?", is generally no. Petrol in Diesel is who to phone, with your engine left off, so it stays that way. Further down, you will find what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to the engine?
Diesel does two jobs on its way through an engine. Oiling comes before burning; it does both. Built to extremely fine gaps, the fuel injectors and your pump rely on your diesel flowing through them to keep their surfaces from wearing against one another.
Of these two tasks, petrol manages the first badly and the second never. A pump running on a petrol mix is wearing itself out, since petrol is thinner than diesel and strips out the protection your fuel system depends on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that is where the knocking comes.
Together, those leave the shape of the problem plain. It is circulation that causes the harm, not contact. Petrol in a tank is a fuel issue. A pump that has been labouring on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with the fuel to your injectors further on.
Four situations our technicians see in New Southgate: how bad is petrol in a diesel?
Fuelled but not once started — as good as it gets. Being at a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With that petrol held in the tank alone, it's emptied and purged right where it stands, and nothing more is needed.
Started for a second, or just the ignition on. With your system primed, the fuel lines and filter now contain petrol that has come from that tank. Still generally straightforward: drain, flush, and your filter sorted.
Those few miles driven were your pump running on fuel diluted by petrol throughout. Tank, lines, filter, then clean fuel run through the entire circuit: that's this work, and the way your car was driven matters as much as the miles. Short trips, like the school run to St Paul's CofE Primary School N11, are one thing. Very different again: a trip to London, under 10 miles away, or any mileage on the M1, under 5 miles from New Southgate, where your engine never stopped running hard.
Driven on till it protested — clattering, smoke, a ragged idle, a soft throttle. What you are hearing is your engine signalling fuel that no longer behaves like diesel. Pull up on the spot — on the verge on Brunswick Park Road, at the kerb, down a side road — and don't move it. A vehicle stopped soon very rarely has lasting damage, because the fuel drain and the flush-through, which still come first, deal with it.
What New Southgate drivers get told about petrol in a diesel — and the myths in it
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up removes nothing; it gives you a fuller tank of the same mix. Percentage isn't how a diesel fuel system tolerates petrol, however much that guidance assumes.
If anything, the opposite holds. Myth: "A current diesel can cope with a bit of petrol." At higher pressure, through more precise components: that's how a modern diesel moves its fuel, and so the protection counts for more, not less.
This is the one that fools people. Myth: "If it starts and drives, there is no harm done." A petrol motor fed diesel usually won't run, so the driver stops and the damage stops with them. Feed petrol to a diesel and it generally fires up, idles and drives away as if nothing has happened — all while its pump is wearing. A running engine doesn't mean fine.
An outdated fix for a different issue is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." It doesn't put back what petrol has diluted, and the petrol is still in the tank after that.
The next start sends petrol back round the pump out of your lines and the fuel filter, where some of it ends up once the motor has been run. That is why draining the tank yourself doesn't sort it — a myth. Also, a can of petrol filled at the kerbside is genuinely dangerous.
Why petrol in a diesel takes place so easily
It's seldom carelessness, and no one does it on purpose. A diesel nozzle generally will not fit a petrol car, yet the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and only in one direction.
When routine and your car stop matching, 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. A forecourt you know, only with its pumps arranged differently. Fuelling up in a hurry en route to the nearest station, with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it takes place. Add rain, a phone call or a back seat full of children, and the hand does what it has always done.
How to prevent petrol in a diesel at your next fill-up in New Southgate
- Read the pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what matters.
- Check the filler flap. Plenty of vehicles state the fuel inside the flap or on the cap. Look at it on your first fill in any vehicle you don't know.
- Mark your key. In a house 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 take the nozzle off the petrol pump. It seems silly and 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 reject a petrol nozzle, and aftermarket devices are available for the remainder. Count it as a backstop, then keep checking the petrol pump.
- Stop as soon as you notice. Less petrol in your tank makes a weaker blend. It does not change what to do next, which is still not to crank it.
Put petrol in a diesel in New Southgate already?
Short and simple, then, is the order of things. Never start it, and don't turn the ignition on. If you're still at the forecourt — BP or anywhere else — ask the staff to help you push the vehicle away from the petrol pump. What got in, roughly how much, and whether it's run: tell us those when you phone 0333 366 0103.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a separate fault — New Southgate has a page just for it.
Why one petrol in a diesel job in New Southgate costs more than another
The four situations above are four different jobs, so no single price for this would be honest. What shifts the cost is chiefly which of them you're in. Beyond that it's the ratio — how much petrol was put in against how much the tank takes — and after that where the car is and whether a van can get to it safely.
Three questions come first, before quoting, instead of after — what went in, how much, has it run — and that is the reason. A range becomes a straight figure when those replies are in.
About New Southgate
New Southgate is a suburban area in Greater London, situated near the banks of the River Lee Navigation at an elevation of around 57 metres. New Southgate lies approximately 7.6 miles from central London and is surrounded by other suburban areas such as Arnos Grove and Friern Barnet. New Southgate has a population of around 9989 people and is predominantly composed of flat dwellings. New Southgate is well connected to the rest of London, with nearby cities and towns including London itself, just 7.4 miles away.
Across Greater London and around New Southgate: fuel drain cover
Our teams answering petrol in diesel jobs in New Southgate, in the N postcode area, also work the locations near it, Arnos Grove, Brunswick Park and Friern Barnet included. Our technicians drain wherever your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the petrol pump around New Southgate?
Then, you could not be in a better place. Turned off it stays; then ring.