Petrol in a Diesel Car in Highcross: How Worried Should You Be?
Likely less than you are now — as long as nobody has started the vehicle. Petrol sitting in a diesel tank does nothing to your engine until something draws it through the fuel system — your ignition priming the pump, the starter, or the drive on its own. So the truthful answer to the first question anyone in Highcross asks, "have I wrecked it?", is generally no. Petrol in Diesel is who to ring, with your engine kept off, and so it stays that way. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and the way to make sure you never repeat it.
Inside your engine: what petrol in a diesel really does
On its way through a motor, diesel does two tasks. It lubricates first, and only then does it burn. What stops the surfaces inside the high-pressure fuel pump and the fuel injectors from wearing down against one another is your diesel passing through them — they're made to extremely fine tolerances.
Of these two jobs, petrol manages the first badly and the second not at all. It's runnier than diesel and strips away the protection the fuel system hinges on, and so a pump running on a petrol mixture is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That is where the clattering comes from.
Combined, those leave the shape of the problem plain. It is movement that does the harm, not contact. Where the petrol is only inside the tank, it is a fault of fuel, nothing more. Whatever a worn pump sheds goes on, carried by the fuel, into the fuel injectors downstream, which is why a pump that has been working on the petrol is where a mechanical fault begins.
How serious is petrol in a diesel? Four scenarios we see around Highcross
Fuelled, and never started: no case is better. At a forecourt, and really only there, that petrol is still limited to the tank — because everywhere else the vehicle was driven to get to it. The task is emptying and flushing on the spot.
Ignition on, or started for a moment. With the fuel system primed, the lines and filter now hold petrol that has come from that tank. Normally little more than emptying, rinsing and sorting the filter, and so still simple.
Driven a few miles. Now the pump has spent those miles working on diluted fuel. Tank, lines, filter, then fresh fuel run through the entire circuit: that's this work, and the way your car was driven matters as much as the miles. A school run to the local primary school is one thing. Very different again: a run to Edinburgh, under 50 miles away, or any distance on the M8, under 50 miles from Highcross, where your engine never stopped labouring hard.
Driven until it protested. Rattling, an uneven idle, smoke, a throttle that has gone soft. That is the motor telling you its fuel has stopped acting like diesel. Whether it is the verge on Ormiston Terrace, a lay-by or a side street, stop there then leave it. The drain and flush still go first, and they deal with it: when a car is stopped quickly, long-term damage is very uncommon.
Myths Highcross people hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A fuller tank of the same mixture is all it gives, since topping up takes out nothing. That guidance supposes a diesel fuel system tolerates petrol by percentage. It doesn't.
If anything, the reverse holds. Myth: "A modern diesel can cope with a bit of petrol." A current diesel sends its fuel through more precise parts at higher pressure, which makes the protection count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools drivers. The motorist of a petrol engine fed diesel usually stops, since it will not run, and the damage stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile the pump grinds. Fine and running are not the same at all.
Myth: "Add some two-stroke oil and drive it home." It is an outdated workaround for a distinct issue. What petrol has thinned remains diluted, and that petrol stays inside that tank anyway.
If your engine has run, part of that petrol sits in the fuel filter and your lines, not the tank — and the next start pulls it straight back through your pump. So the myth "drain that tank yourself and you are sorted" does not hold. Emptying petrol into a can by the kerbside is also really risky.
How does petrol in a diesel occur?
No one does it on purpose, and it is seldom carelessness. A diesel nozzle mostly won't go into a petrol car, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake easy, and just in one direction.
The moment habit stops matching the car is the moment it occurs. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. Your usual forecourt, its pumps now in a different order. Fuelling up in a rush en route to Tweedbank, with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it occurs. With rain, a call coming in, or a car full of children to deal with, the hand simply does what it always has.
Next time you fill up in Highcross: avoiding petrol in a diesel
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most usually do. Read the pump's label; the colour is only a clue.
- Inspect your filler flap. Plenty of vehicles state the fuel type inside the flap or on the cap. Look at it on your first fill in a motor you do not know.
- One of each in the home? Label the key to the diesel — a bright fob, a sticker — since meaning to remember isn't enough.
- It sounds silly and it does the trick: on the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump.
- While you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Some diesels come with a filler built to block 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.
- Less petrol means a thinner blend, so stop as soon as you realise — while remembering that your next step is unchanged. It is still not to fire it up.
Put petrol in a diesel around Highcross already?
In that case, there is only a short order of things. Leave it unstarted, with your ignition off as well. Still at the forecourt, at BP or anywhere else? Ask the attendants to help you roll the car clear of the petrol pump. Next, 0333 366 0103. We will ask what was put in, about how much, and if it has been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a different issue — Highcross has a page just for it.
Why one petrol in a diesel task in Highcross costs more than another
A fair single quote doesn't exist here: four scenarios, four separate jobs. What moves the cost is chiefly which of them you are in. Two things follow that: the petrol that got in as a proportion of what the tank holds, then the spot the car is in and whether a technician can reach it safely.
Three queries come first, before quoting, rather than after — what went in, how much, has it run — and this is the reason. Their replies are what change a range into one firm number.
About Highcross, for a moment
Highcross is a suburban area situated on the riverside in the Scottish Borders, with a mix of detached housing and a population of around 1107 residents. Highcross sits at an elevation of 103 metres, close to the nearby settlements of Darnick, Melrose, and Dingleton. Highcross is located approximately 30 miles from Edinburgh, the capital city of Scotland, and is part of the wider commuter belt. Highcross enjoys a scenic setting, with the River Tweed flowing nearby.
Fuel drain cover in Highcross and across Scottish Borders
The vans answering petrol in diesel calls in Highcross, in the TD postcode area, equally work the places near it, Darnick, Melrose and Dingleton included. We drain wherever the car is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the pump in Highcross?
Then you are in the best position there is. Phone, and keep it turned off.