Should You Worry? Petrol in a Diesel Car in New Barnet
If it has not been started, worry far less than you probably are. Till the ignition primes your pump, the starter cranks, or the vehicle is driven, petrol in a diesel tank simply sits there and does nothing. Which makes the truthful reply to that first New Barnet query — "have I wrecked it?" — normally no. Petrol in Diesel is who to ring, with your motor kept off, so it remains that way. What petrol actually does to a diesel, how to gauge how far it has gone, and how to keep it from happening a second time: that's the remainder of this page.
The motor and petrol in a diesel: what goes on
Two tasks fall to diesel on its route through a motor. It protects to begin with, and only then does it burn. Extremely fine tolerances go into the injectors and the high-pressure fuel pump, and just the diesel flowing through keeps those surfaces from grinding together.
Petrol handles the first job poorly and the second not at all. A pump running on a petrol blend is wearing itself out, because petrol is runnier than diesel and strips out the protection your fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where the clattering starts.
Seen together, they make clear the shape the trouble takes. Contact does not do the damage — movement does. Any tank with petrol in it is a fuel issue. The start of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors beyond it.
Four situations we see around New Barnet: how bad is petrol in a diesel?
Filled up, never started. The best case there can be. Being at a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With that petrol held in the tank alone, it's drained and rinsed on the spot, and nothing more is needed.
Started for a second, or only your ignition on. Petrol has come out of that tank and got to your filter and the lines, because the system has been primed. Usually nothing more than emptying, cleaning and seeing to the filter, so still simple.
The pump has worked a couple of miles on diluted fuel — that is what driving the car does. Tank, lines, filter, then fresh fuel put through the entire circuit: that's the work, and the way your car was driven counts as much as the miles. Short trips, such as the school run to Cromer Road Primary School, are one thing. Any distance on the M25, under 3 miles from New Barnet, means the engine has worked hard throughout, and a run to St Albans, under 10 miles away, is a very different task too.
Driven on until it complained — clattering, smoke, a ragged idle, a dead throttle. The motor is telling you the fuel is no longer behaving like diesel. Leave it wherever it stops: a lay-by, a quiet street, the verge on Station Road. A car stopped quickly very seldom has permanent damage, as the drain and the flush, which still come first, deal with it.
New Barnet drivers and that petrol in a diesel myths they hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A bigger tank of the same mixture is all you get, because topping up removes nothing. That guidance supposes a diesel fuel system tolerates petrol by percentage. It doesn't.
"Newer diesels can handle a little petrol" — a myth, and closer to the opposite. At higher pressure, through smaller components: that is how a newer diesel handles its fuel, and so the protection counts for more, not less.
One myth that catches drivers off guard: if it starts and drives, it must be unharmed. Any petrol engine fed diesel generally won't run, so the motorist stops and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump grinds. Being able to run isn't the same as being fine.
An outdated workaround for a separate issue lies behind this one. Myth: "Add some two-stroke oil and drive the car home." That petrol is still in your tank afterwards, and what it has thinned isn't put back.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol sits in the filter and lines, waiting to go straight back through your pump on the next start. Draining petrol into a can at the kerbside is also truly dangerous.
Petrol in a diesel: how does it take place?
A careless moment is rarely the cause, and nobody means to do it. One way only, because of the nozzles: the smaller petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one generally won't fit a petrol motor. That's how the forecourt makes it easy.
Habit and the car getting out of step is when it takes place. Courtesy car, hire car, or a vehicle that's brand new. Two cars on one drive, one petrol, one diesel. A familiar forecourt with the pumps in a different order. A train to catch, and a hurried fill en route to the nearest station. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
New Barnet motorists: how to avoid 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. Check the petrol pump's label; the colour is only a hint.
- Check your filler flap. Many vehicles state the fuel type inside the flap or on the cap. Look at it on your first fill in a car you don't know.
- Label your key. In a house with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- It seems daft and it works: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump.
- Mistakes like this are easy to make whilst your mind is on something else, and so your phone goes away.
- Add-on devices are available for vehicles without one, and some diesels are built with a filler that won't take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Stop the moment you notice. Less petrol inside that tank means a weaker mixture. It doesn't change what to do next, which is still not to start the vehicle.
Already put petrol in a diesel in New Barnet?
Short and simple, then, is the order of things. Do not turn the ignition on, and do not start it. If you are still on the forecourt — Shell or anywhere else — ask the attendants to help you push the vehicle away from the petrol pump. What got in, roughly how much, and if it's run: tell us those when you call 0333 366 0103.
Say so if it was AdBlue instead of petrol: it is a separate problem, with its own page for New Barnet, since AdBlue brings corrosion and deposits instead of lost protection.
New Barnet petrol in a diesel tasks: why one costs more than another
A fair single quote does not exist here: four scenarios, four separate tasks. Mostly, your cost moves with which situation you're in. The ratio matters next, meaning how much of your tank is petrol, and then the location of the car and whether getting to it is safe for our van.
That is why our technicians ask three questions before costing instead of after: what went in, how much, and whether it has run. A range becomes a straight figure when the replies are in.
About New Barnet and where it is
New Barnet is a suburban area in Greater London, situated near the River Lea and close to the Hertfordshire border. New Barnet sits at an elevation of around 75 metres, with nearby towns including Barnet and St Albans. New Barnet has a mix of housing types, but is predominantly composed of flats, and is located approximately 10 miles from central London. New Barnet is also near other local areas such as Underhill and East Barnet.
Fuel drain cover in New Barnet and across Greater London
Barnet, Underhill and East Barnet are among the locations near New Barnet that the same vans work, answering petrol in diesel call-outs across New Barnet's EN postcode area. Our technicians drain where your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
In New Barnet and still at the petrol pump?
Then, you couldn't be in a better spot. Keep it off. Ring.