Petrol in a Diesel Car in Raven Hill: How Worried Should You Be?
Less than you probably are, if it hasn't been started. "Have I wrecked it?" is the first question anyone around Raven Hill asks, and the truthful answer is generally no, because petrol left in a diesel tank hurts nothing until it is dragged through the fuel system — by ignition priming, by your starter, or by being driven. Keep it like that: leave your engine off and phone Petrol in Diesel. What petrol really does to a diesel, how to judge how far it's travelled, and how to keep it from happening a second time: that is the rest of this page.
What petrol in a diesel does to your engine
Diesel has two tasks on its way through an engine. Before it combusts, it lubricates — then it ignites. Your high-pressure pump and the fuel injectors are designed to extremely fine tolerances, and the diesel passing through them is what keeps those surfaces from wearing against one another.
Petrol handles the first task poorly and the second not at all. A pump running on a petrol mix is wearing itself out, because petrol is thinner 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 wants from its fuel — and that's where any clattering comes.
Together, those make the shape of the issue plain. It is circulation that does the harm, not contact. Petrol in a tank is a fuel issue. After your pump has been running on that petrol, a mechanical issue has started: anything shed by a pump that's grinding travels downstream to the fuel injectors with the fuel.
How serious is petrol in a diesel? Four situations we see in Raven Hill
Fuelled, and not started: nothing beats it. Being at a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol held inside that tank alone, it's emptied and rinsed right where it stands, and nothing more is needed.
Ignition on, or started for a second. Once primed, the system has drawn petrol from the tank as far as your filter and the fuel lines. Usually nothing more than emptying, purging and sorting the filter, and so still straightforward.
Driven a couple of miles. Now the pump has spent these miles running on thinned fuel. Tank, lines, filter, then fresh fuel run through the entire system: that's this work, and the way your car was driven matters as much as the distance. The school run to the local primary school is one matter. Very different a second time: a run to Swansea, under 3 miles away, or some mileage on the M4, under 3 miles from Raven Hill, where the motor never stopped running hard.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven until it complained. The motor is telling you your fuel is no longer acting like diesel. Whether it's the verge on Ravenhill Road, a lay-by or a side road, stop where you are then leave it. A car stopped soon very seldom has lasting damage, because the drain and the flush-through, which still go first, take care of it.
Myths Raven Hill motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It doesn't. Nothing is removed when you top up — that tank just carries more of the same mixture. The assumption behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: a current diesel copes with a bit of petrol. Rather, the opposite. A modern diesel sends its fuel through finer components at higher pressure, which makes the lubrication count more, not less.
This is the one that catches drivers. Myth: "If it starts and drives, there is no damage done." The motorist of a petrol motor fed diesel usually stops, since it will not run, and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump grinds. Being able to run isn't proof of being fine.
An outdated fix for a separate problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has diluted remains weakened, and that petrol stays inside the tank regardless.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol lies in the fuel filter and lines, waiting to go straight back through the pump on the next start. It is also really dangerous to drain petrol into a can by the kerbside.
How petrol ends up: petrol in a diesel
It is rarely carelessness, and no one does it on purpose. One way only, because 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 motor. That is how the forecourt makes it simple.
Routine and the car falling out of step is how it occurs. A new vehicle, a hire car or a courtesy car. One petrol and one diesel on the drive of the same household. The pumps in a different order on a well-known forecourt. A hurried fill on the way to Swansea with a train to catch. A new-to-you diesel Volkswagen Passat, its first fuelling, and a motorist used to petrol: exactly when it occurs. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it has always done.
Preventing petrol in a diesel next time you fill up in Raven Hill
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most usually do. Check the petrol pump's label; the colour is only a hint.
- Plenty of cars state the fuel inside the filler flap or on the cap, and so check there on your first fill in any car you do not know.
- Label the 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 meaning to remember.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It seems daft and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so tuck the phone away then keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to block a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop reading the pump.
- As soon as you realise, stop: less petrol in that tank makes a thinner blend. What to do next does not change, though — still don't crank it.
Put petrol in a diesel in Raven Hill already?
Short and simple, then, is the order of things. Starting it is out, and so is switching on the ignition. Yet at the forecourt, at Applegreen or anywhere else? Ask the attendants to help you roll it away from the petrol pump. Then call 0333 366 0103 and tell us what got in, roughly how much, and whether it has run.
If it was AdBlue and not petrol, say so. That's a different issue — corrosion and deposits instead of lost protection — and it has its own page for Raven Hill.
One petrol in a diesel task around Raven Hill costs more than another. Why?
There's no honest single price for this, since the four situations above are four separate jobs. The situation itself does most of the work of moving the cost. The ratio matters next, meaning how much of your tank is petrol, and then the position of the vehicle and whether reaching it is safe for a van.
Ahead of any quote, not after, come three questions: your fuel that went in, the quantity, and whether it's run. That is why. Their replies are what turn a range into one firm number.
About Raven Hill itself
Raven Hill is a suburban area located on the outskirts of Swansea, situated near the coast in south Wales. Raven Hill sits at an elevation of 107 metres, overlooking the surrounding landscape and the nearby city of Swansea. Raven Hill is characterised by its predominantly semi-detached housing stock, with nearby neighbourhoods including Gendros, Cockett, and Caer-eithin.
Fuel drain cover across Swansea, Raven Hill included
Raven Hill waits in the SA postcode area, and our teams that answer petrol in diesel calls there work the places near it as well — Gendros, Cockett and Caer-eithin among them. No need to move the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations where we work.
Raven Hill: still at the pump?
In that case, you couldn't be in a better position. Phone, and leave it turned off.