Petrol in a Diesel Car in Hope: How Worried Should You Be?
If it has not been started, worry far less than you probably are. Until the ignition primes the pump, the starter turns, or the car is driven, petrol in a diesel tank simply waits there and does nothing. Which makes the truthful reply to the first Hope query — "have I ruined it?" — usually no. Petrol in Diesel is who to call, with the motor kept off, and so it remains that way. What petrol actually does to a diesel, how to judge how far it has gone, and how to keep it from happening again: that is the remainder of this page.
Inside your engine: what petrol in a diesel does
Diesel does two tasks on its way through an engine. Oiling comes before burning; it does both. What keeps 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 very fine clearances.
Badly at the first, not at all at the second: that is petrol. A pump working on a petrol mix is wearing itself out, since petrol is runnier than diesel and strips out the protection your fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel needs from its fuel — and that's where the clattering starts.
The shape of the trouble is clear once you put those together. It is circulation that causes the damage, not contact. Petrol in a tank is a fuel issue. The start of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds moves on with the fuel to the fuel injectors beyond it.
Petrol in a diesel in Hope: how bad is it? Four situations
The best case there can be: filled up, not once started. Being at a forecourt is what makes this the case: elsewhere, your car has been driven there to begin with. With the petrol held inside that tank alone, it is emptied and rinsed on the spot, and nothing more is needed.
A moment's running, or merely the ignition on. Once primed, the system has pulled petrol out of your tank up to the fuel filter and your lines. That's usually still a straightforward job — a drain, a flush, and the fuel filter dealt with.
Driven a few miles. Now the pump has spent these miles running on weakened fuel. Tank, lines, filter, then clean fuel run through the entire system: that's this work, and the way your car was driven matters as much as the distance. On the school run to Hope Primary School, the mileage is short. Any miles on the M67, under 15 miles from Hope, means the motor has worked hard throughout, and a run to Sheffield, under 15 miles away, makes a very different job too.
Driven until it complained. Clattering, a lumpy idle, smoke, a throttle that has gone soft. That's your engine telling you its fuel has stopped behaving like diesel. Whether it's the verge on Station Road, a lay-by or a side street, stop where you are and leave it. What comes first is still the fuel drain and flush, and that deals with it, with lasting damage very rare if a vehicle is stopped soon.
What Hope motorists get told about petrol in a diesel — and the myths in it
False: topping up to full with diesel makes it fine. It doesn't. Topping up takes out nothing; it gives you a fuller tank of the same mixture. The idea behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the reverse is true. Myth: "A current diesel can cope with a bit of petrol." Protection counts more on current diesels, not less, because their fuel runs through more precise parts at higher pressure.
"It starts, it drives, so no harm done" — the myth that catches more motorists than any other. Feed diesel to a petrol engine and it normally will not run, so the driver stops — and the damage stops with them. While the pump wears, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. A running engine does not mean fine.
An outdated fix for a distinct problem lies behind this one. Myth: "Add some two-stroke oil and drive it home." The petrol is still inside that tank after that, and whatever 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 it ends up once your engine has been run. That is why a DIY tank drain does not sort it — a myth. It is also truly hazardous to drain petrol into a can at the roadside.
Why petrol in a diesel takes place at all
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle generally will not go into a petrol motor, yet the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in that direction.
The moment routine stops matching your car is the moment it happens. Courtesy car, hire car, or a vehicle that is brand new. Two motors on one driveway, one petrol, one diesel. Your usual forecourt, its pumps now in a different order. A train to catch, and a rushed fill on the way to Hope (Derbyshire). A new-to-you diesel Renault Megane, its first fuelling, and a motorist accustomed to petrol: exactly when it occurs. Add a back seat full of children, a phone call or rain, and the hand wins.
Next time you fill up in Hope: avoiding petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on every forecourt. The label is what matters.
- In a motor you don't know, look inside the flap over your filler or at the cap before the first fill: plenty of cars print the fuel there.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, for a household with one of each.
- It seems silly and it works: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away and keep your mind on the pump.
- Some diesels have a filler designed to refuse a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the pump.
- Stop as soon as you realise. Less petrol inside your tank means a thinner mixture. It doesn't change what to do next, which is still not to start the car.
Petrol already in a diesel around Hope? Start here
Then, there is only a short order of things. Don't turn your ignition on, and do not fire it up. Still on the forecourt, at the nearest petrol station or anywhere else? Ask the staff to help you roll it clear of the petrol pump. What got in, roughly how much, and if it has run: tell us that when you phone 0333 366 0103.
Say so if it was AdBlue rather than petrol: it's a different problem, with its own page for Hope, because AdBlue brings corrosion and deposits rather than lost protection.
Hope petrol in a diesel jobs: why one costs more than another
There's no fair single price for this, since the four situations above are four different jobs. What moves the cost is mostly which of them you're in. Two things follow that: the petrol that was put in as a proportion of what the tank takes, then the place the vehicle is in and whether a technician can get to it safely.
Ahead of any quote, not after, come three queries: the fuel that was put in, the amount, and if it has run. That is why. The replies change a range into a straight figure.
About Hope and its setting
Hope is a village in Derbyshire, situated on the banks of the River Noe in the East Midlands region of England. Hope sits at an elevation of 171 metres, surrounded by rolling hills and scenic countryside, with nearby villages including Aston, Brough, and Smalldale. Hope is located approximately 11.5 miles from the city of Sheffield and 144.2 miles from London, with a population of around 849 residents living in predominantly semi-detached housing.
Fuel drain cover around Hope and across Derbyshire
Aston, Brough and Smalldale are among the spots around Hope that the same vans work, answering petrol in diesel call-outs across Hope's S postcode area. The vehicle does not need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Hope: still at the petrol pump?
Then you're in the best position there can be. Turned off it remains; then ring.