Hatfield Hyde: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — as long as no one has started the vehicle. Until the ignition primes the pump, your starter cranks, or your car is driven, petrol in a diesel tank simply rests there and does nothing. Which makes the truthful reply to that first Hatfield Hyde query — "have I ruined it?" — normally no. Leave your engine off then phone Petrol in Diesel — that is how you keep it that way. The rest of this page explains what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you a second time.
What petrol in a diesel does to the engine
Two jobs fall to diesel on its route round a motor. Before it combusts, it protects — then it ignites. What keeps the surfaces inside the high-pressure pump and your injectors from wearing down against each other is your diesel flowing through them — they are designed to very fine gaps.
The second task petrol doesn't do at all, and the first it does poorly. The rattling comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips out the lubrication your system hinges on, and any pump working on that mix is wearing itself.
Taken together, they show the shape the issue has. Contact doesn't do the harm — movement does. Where that petrol is only in your tank, it is an issue of fuel, nothing more. A pump that has been running on that petrol is the start of a mechanical one, and whatever a worn pump sheds moves on with the fuel to your injectors further on.
Hatfield Hyde, petrol in a diesel: four cases, from mild to significant
Filled but not once started — as good as it gets. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With the petrol kept in your tank alone, it's drained and flushed right where it stands, and nothing more is needed.
Started for a moment, or just the ignition on. Once primed, your system has drawn petrol from that tank as far as the filter and the lines. Still normally straightforward: drain, flush, and your filter sorted.
Driven a couple of miles. Now the pump has spent these miles working on diluted fuel. How hard the car was driven counts as much as how far, and this work takes in that tank, the lines, the filter and clean fuel through the entire circuit. Driving the kids to Creswick Academy is one sort of trip. Any mileage on the A1(M), under a mile from Hatfield Hyde, means the motor has worked hard throughout, and a run to St Albans, under 10 miles away, is a very different job too.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. The motor is telling you your fuel is no longer behaving like diesel. Whether it's the verge on Howlands, a lay-by or a side street, stop where you are then leave it. The fuel drain and flush-through still go first, and they take care of it: if a car is stopped early, long-term damage is very unusual.
Hatfield Hyde people and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Topping up removes nothing; it gives you a bigger tank of the same mixture. The idea behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A modern diesel can cope with a bit of petrol." More precise components and higher pressure are how a current diesel runs its fuel, and that makes the lubrication matter more, not less.
"It starts, it drives, so no harm done" — the myth that catches more people than any other. Feed diesel to a petrol engine and it usually won't run, and 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 will; meanwhile your pump grinds. Being able to run isn't proof of being fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an old workaround for a distinct issue. What petrol has thinned stays thinned, and that petrol remains in that tank regardless.
The next start sends petrol back round your pump out of the lines and the fuel filter, where some of that sits once the motor has been run. That's why a DIY tank drain does not leave you sorted — a myth. Also, a can of petrol drained at the kerbside is genuinely hazardous.
Petrol in a diesel: how does it take place?
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle generally won't go into a petrol vehicle, yet the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in one direction.
It occurs when habit and your car stop matching. Courtesy car, hire car, or a motor that's brand new. A household with one petrol and one diesel on the driveway. The pumps in a different order on a well-known forecourt. A train to catch, and a rushed fill on the way to Welwyn Garden City. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it happens. With rain, a call arriving, or a car full of children to deal with, your hand just does what it has always done.
Next time you fill up around Hatfield Hyde: preventing petrol in a diesel
- A green handle for unleaded and black for diesel is usual in the UK — but not on every forecourt. Go by the label on the pump, not the colour.
- 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 do not know.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a house with one of each.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It sounds daft and it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away then keep your mind on the pump.
- Some diesels come with a filler built to block a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Stop as soon as you notice. Less petrol in that tank means a weaker mix. It does not change what to do next, which is still not to start it.
Put petrol in a diesel in Hatfield Hyde already?
Then, there is only a short order of things. Starting it is out, and so is turning on your ignition. Ask the staff to help you push it away from the pump if you're still on the forecourt, whether that's Shell or somewhere else. Next, 0333 366 0103. We'll ask what got in, roughly how much, and if it's been run.
Corrosion and deposits form the problem with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and read its own Hatfield Hyde page.
Hatfield Hyde petrol in a diesel tasks: why one costs more than another
There's no honest single price for this, since the four situations above are four different jobs. Which of them you are in is chiefly what moves the cost. The share matters next, meaning how much of that tank is petrol, followed by the location of the car and whether getting to it is safe for our van.
Ahead of any quote, not after, we ask three queries: your fuel that got in, its amount, and whether it has run. That is why. Given those answers, there is a straight figure instead of a range.
About Hatfield Hyde and where it is
Hatfield Hyde is a suburban area in Hertfordshire, situated approximately 19.5 miles north of London and 6.2 miles southeast of St Albans. Hatfield Hyde sits at an elevation of around 79 metres, near the villages of Woodhall, Mill Green, and Peartree. Hatfield Hyde is characterized by its predominantly terraced housing stock, which reflects the typical residential development patterns of the region. Hatfield Hyde remains a relatively small community, with a population of around 4984 residents.
Hatfield Hyde and Hertfordshire: where our fuel drain cover reaches
Hatfield Hyde rests in the AL postcode area, and our vans that answer petrol in diesel call-outs there work the spots near it as well — Woodhall, Mill Green and Peartree among them. The car doesn't need to move to us: our engineers drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
At the petrol pump in Hatfield Hyde, still?
No position is better: that is where you now are. Leave the vehicle switched off, then ring.