How Worried Should You Be? Petrol in a Diesel Car in New Boston
Far less than you probably are, provided it has not been started. Till your ignition primes your pump, the starter turns, or your car is driven, petrol in a diesel tank just sits there and does no harm. Which means the truthful reply to the first New Boston query — "have I wrecked it?" — normally no. Leave the motor off then phone Petrol in Diesel — that is how you keep it like that. Keep reading for three things: the effect petrol has inside a diesel engine, the signs of how far it has got, and ways to make sure you don't do it again.
The engine and petrol in a diesel: what happens
Passing through an engine, diesel is doing two jobs at once. It protects to begin with, and only then does it burn. Very fine tolerances go into the fuel injectors and the high-pressure pump, and just the diesel running through stops their surfaces grinding together.
Petrol does the first task poorly and the second not at all. A pump working on a petrol blend is wearing itself out, because petrol is runnier than diesel and takes away the lubrication the fuel system depends on. Petrol is also made to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that is where any rattling comes.
Put these together and the shape of the issue is clear. Contact doesn't do the damage — movement does. Where the petrol is only inside that tank, it is a fault of fuel, nothing more. Once your pump has been labouring on that petrol, a mechanical problem has begun: whatever is shed by a pump that's wearing is carried downstream to your injectors with the fuel.
How serious is petrol in a diesel? Four scenarios we see around New Boston
Filled but not once started — the best it gets. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol kept inside your tank alone, it's emptied and flushed on the spot, and nothing more is needed.
Your ignition turned on, or a brief start. The fuel system has been primed, so petrol has left that tank and got to the filter and the lines. Still generally straightforward: drain, flush, and the filter sorted.
A couple of miles driven, and your pump has spent each of them labouring on weakened fuel. The work is the tank, the lines, the fuel filter and fresh fuel through the entire system, and how hard the vehicle was driven matters as much as how far. Short trips, like the school run to Haydock English Martyrs' Primary School, are one thing. Driving as far as Liverpool, under 15 miles away, makes a very different job — as does any distance on the M6, under 3 miles from New Boston, with the engine labouring hard the whole time.
Driven till it complained. Knocking, 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 wherever you are — the verge on Sherlock Avenue, a lay-by, a side street — then leave the vehicle where it is. A car pulled over soon very rarely has long-term damage, as the fuel drain and the flush-through, which still go first, take care of it.
What New Boston motorists get told about petrol in a diesel — and the myths in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing is removed when you top up — your tank simply carries more of the same blend. The assumption behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. A modern diesel runs its fuel through finer components at higher pressure, which makes the lubrication matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there is no damage done." The motorist of a petrol motor fed diesel normally stops, since it will not run, and the damage stops with them. Feed petrol to a diesel and it normally starts, ticks over and pulls away as if nothing happened — all the while its pump wears. Running does not mean fine.
Not so: a two-stroke additive lets you to drive home. It was an old workaround, meant for another problem. That petrol is still inside that tank afterwards, and what it has thinned is not put back.
Once your engine has run, part of the petrol sits in the fuel filter and your lines, not your tank — and the next start pulls it straight back through the pump. So the myth "drain the tank yourself and you are sorted" does not stand up. Also, a can of petrol filled at the roadside is genuinely dangerous.
How does petrol in a diesel happen?
It is seldom carelessness, and nobody does it on purpose. One way only, since of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol vehicle. That is how the forecourt makes it straightforward.
The moment habit stops matching your car is the moment it happens. Courtesy car, hire car, or a motor that's new. Two motors on one drive, one petrol, one diesel. A well-known forecourt with the pumps in a different order. Rushing for a train outside Garswood and fuelling up en route. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Volkswagen Passat for the first time. Throw in rain, a phone call or a back seat full of kids, and the hand does what it has always done.
Preventing petrol in a diesel next time you fill up around New Boston
- A green handle for unleaded and black for diesel is usual in the UK — but not on each forecourt. Trust the label on the petrol pump, not the colour.
- The first fill in a strange motor is the time to check the filler flap — inside it, or on the cap, many cars state which fuel they take.
- Good intentions count for less than a sticker or a fob in a bright colour on the diesel's key when a house has one of each. So mark it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It sounds daft and it does the trick.
- Tuck the phone away. This is an easy mistake to make whilst you are thinking about something else.
- Add-on devices exist for cars without one, and some diesels are built with a filler that won't take a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label.
- The moment you realise, stop: less petrol inside your tank makes a thinner mix. What to do next doesn't change, though — still do not start the vehicle.
Put petrol in a diesel around New Boston already?
The order of things is brief, then. Leave it unstarted, with your ignition off too. Ask the staff to help you roll it clear of the pump if you're still at the forecourt, whether that is Tesco or anywhere else. Call 0333 366 0103 next, with three answers — your fuel, the approximate amount, and whether it's run.
Say so if it was AdBlue rather than petrol: it is a separate fault, with its own page for New Boston, because AdBlue brings corrosion and deposits rather than lost protection.
Why one petrol in a diesel job around New Boston costs more than another
The four situations above are four different jobs, so no single price for this would be honest. The situation itself does most of the work of moving your cost. Two things come after that: the petrol that was put in as a share of what that tank takes, then the place the car is in and whether our van can reach it safely.
That is why our engineers ask three queries before quoting rather than after: what went in, how much, and whether it has run. A range becomes a straight figure once the replies are in.
About New Boston
New Boston is a suburban area in Merseyside, situated inland at an elevation of around 50 metres, with semi-detached housing being the predominant type of accommodation. New Boston lies approximately 13.7 miles from Liverpool and 172.4 miles from London, placing it within the North West region of England. New Boston is surrounded by other nearby places, including North Florida, Haydock, and Old Boston. New Boston has a population of around 5356 residents.
New Boston and Merseyside: where our fuel drain cover runs
Petrol in diesel call-outs in New Boston — part of the WA postcode area — go to vans that also cover the locations around it, North Florida, Haydock and Old Boston among them. No need to move your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
In New Boston and still at the pump?
The best place there is, then — that is where you are. Turned off it remains; then ring.