How Worried Should You Be? Petrol in a Diesel Car in Hurl Field
Unstarted? Then less anxious than you probably feel. Everyone in Hurl Field begins with "have I wrecked it?", and the honest answer is normally no: petrol left in that tank of a diesel remains harmless until priming, cranking or driving draws it into your fuel system. Petrol in Diesel is who to call, with your motor kept off, so it remains that way. The remainder of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you again.
What petrol in a diesel does to the motor
On its way through a motor, diesel does two jobs. Oiling comes before burning; it does both. What keeps the surfaces inside your high-pressure pump and the fuel injectors from wearing against one another is your diesel passing through them — they're built to very fine gaps.
Badly at the first, not at all at the second: that is petrol. Being less viscous than diesel, petrol strips away the protection a fuel system needs, so a pump running on the mixture wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the knocking.
The shape of the problem is clear when you put those together. It is circulation that does the damage, not contact. Where that petrol is only inside your tank, it's an issue of fuel, nothing more. The start of a mechanical problem is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with the fuel to your injectors downstream.
Hurl Field, petrol in a diesel: four cases, from mild to significant
The best case there is: filled up, not once started. Being at a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol kept in the tank alone, it's emptied and cleaned right where it stands, and nothing more is needed.
The ignition switched on, or a short start. With the system primed, the fuel lines and filter already contain petrol that has come from that tank. Drain, flush, deal with the fuel filter: still normally simple.
Some miles driven, and the pump has spent each of them labouring on diluted fuel. How hard the car was driven counts as much as how far, and this work covers your tank, the lines, the fuel filter and clean fuel through the entire circuit. A school run to Bankwood Primary School is one matter. Very different again: a trip to Sheffield, under 3 miles away, or some mileage on the M1, under 5 miles from Hurl Field, where the engine never stopped running hard.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone ragged. That is the engine telling you its fuel no longer is behaving like diesel. Pull up wherever you are — the verge on Gleadless Road, a lay-by, a side street — and leave the car where it is. Lasting damage is very rare if a vehicle is pulled over quickly, and the drain and flush that still come first deal with it.
What Hurl Field drivers get told about petrol in a diesel — and the myths in it
Myth: 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. That advice presumes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the reverse. More precise parts and higher pressure are how a current diesel runs its fuel, and that makes the protection count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools people. Diesel in a petrol motor usually means a motor that will not run: the motorist stops, and so does the harm. Feed petrol to a diesel and it generally starts, ticks over and pulls away like nothing has happened — all while its pump wears. Being able to run isn't proof of being fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a different fault. None of what petrol thinned gets put back by it — and later, that tank still holds that petrol.
Once your engine has been run, part of the petrol sits in the filter and the lines, not your tank — and your next start pulls it right back through your pump. So the myth "drain that tank yourself and you're sorted" does not hold. Also, a can of petrol drained by the roadside is genuinely risky.
How petrol ends up: petrol in a diesel
Nobody does it on purpose, and it is rarely carelessness. A diesel nozzle mostly will not go into a petrol car, but the narrower petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in one direction.
When habit and the car stop matching, it happens. Hire cars, courtesy cars, and motors that are new to you. A household with one petrol and one diesel on the driveway. The pumps in a different order on a familiar forecourt. Fuelling up in a rush en route to Sheffield, with a train to catch. A new-to-you diesel Skoda Octavia, its first fuelling, and a motorist used to petrol: precisely when it happens. Your hand does what it has always done once you add rain, a phone call or a back seat full of kids.
Avoiding petrol in a diesel next time you fill up in Hurl Field
- The label is what matters, and so check the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, yet not on each forecourt.
- In a vehicle you do not know, look inside the flap over your filler or at the cap before your first fill: many cars state the fuel type there.
- One of each in the household? Mark the key to the diesel — a coloured fob, a sticker — since meaning to remember is not enough.
- 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 seems silly and it works.
- Thinking about something else is when this becomes an easy mistake to make, so put your phone away then keep your mind on the pump.
- Some diesels have a filler designed to reject a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump.
- As soon as you notice, stop: less petrol in the tank makes a weaker blend. What to do next does not change, though — still do not fire it up.
Hurl Field: already put petrol in a diesel?
The order of things is short, then. Don't turn your ignition on, and don't start it. Ask the attendants to help you roll it clear of the pump if you are still on the forecourt, whether that's Harvest Energy or somewhere else. Phone 0333 366 0103 next, with three answers — the fuel, the approximate amount, and whether it's run.
If it was AdBlue and not petrol, say so. That's a different fault — corrosion and deposits and not lost lubrication — and it has its own page for Hurl Field.
One petrol in a diesel task around Hurl Field costs more than another. Why?
The four situations above are four different tasks, so no single price for this would be fair. The situation itself does most of the work of moving the cost. Two things come after that: the petrol that was put in as a share of what that tank holds, then the place the car is in and whether a technician can get to it safely.
That's why we ask three queries before quoting instead of after: what got in, how much, and whether it's run. Given those replies, you get a straight figure rather than a range.
About Hurl Field, for a moment
Hurl Field is a suburban area situated near the River Don in South Yorkshire, with Hurl Field being close to the city of Sheffield and having an elevation of 197 metres. Hurl Field is characterised by its semi-detached housing and is located near other residential areas such as Gleadless Valley and Common Side. Hurl Field has a population of approximately 6673 residents and is within walking distance of Sheffield's amenities. Hurl Field is also near the Rollestone area, which adds to its residential appeal.
Fuel drain cover around Hurl Field and across South Yorkshire
Gleadless Valley, Common Side and Rollestone are among the spots near Hurl Field that the same vans work, answering petrol in diesel call-outs across Hurl Field's S postcode area. We drain wherever your car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
In Hurl Field and still at the petrol pump?
No position is better: that is where you are. Keep it off. Ring.