How Worried Should You Be? Petrol in a Diesel Car in Pembroke Dock
Less than you likely are, if it hasn't been started. Petrol resting in a diesel tank does nothing to the engine until something draws it through your fuel system — your ignition priming the pump, the starter, or the drive on its own. So the fair answer to the first query anyone in Pembroke Dock asks, "have I wrecked it?", is generally no. Petrol in Diesel is who to call, with the engine kept off, so it remains that way. What petrol actually does to a diesel, how to gauge how far it has gone, and how to keep it from happening again: that's the remainder of this page.
What petrol in a diesel does to your engine
Two jobs fall to diesel on its route round a motor. It burns, and before it combusts it protects. The high-pressure fuel pump and your injectors are designed to very fine tolerances, and your diesel passing through them is what stops those surfaces from wearing against each other.
Of these two jobs, petrol handles the first poorly and the second never. Being less viscous than diesel, petrol strips away the protection a fuel system needs, leaving a pump on the blend to wear itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is where you get the rattling.
Put these together and the shape of the issue is plain. The damage is done by circulation, not by contact. Where the petrol is only in the tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds goes on, borne by the fuel, into the injectors downstream, which is why a pump that has worked on that petrol is where a mechanical issue begins.
Petrol in a diesel around Pembroke Dock: how bad is it? Four situations
Fuelled up, never started. The best case there can be. That petrol is in that tank and only your tank, and the task is a drain and a flush where the vehicle sits. This is the one situation that can only really happen on a forecourt, since anywhere else the vehicle has been driven to get there.
Ignition on, or started for a moment. With the fuel system primed, your lines and filter already hold petrol that has come from the tank. Drain, flush, deal with the filter: still usually straightforward.
Some miles driven, and the pump has spent each of them running on weakened fuel. The work is that tank, the lines, your filter and fresh fuel through the entire circuit, and how hard the vehicle was driven counts as much as how far. Driving the kids to the local primary school is one kind of trip. Very different once more: a trip to St Davids, under 25 miles away, or some miles on the M4, under 50 miles from Pembroke Dock, where your engine kept labouring hard.
Driven on till it protested — clattering, smoke, a lumpy idle, a dead throttle. That is the engine telling you its fuel has stopped behaving like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Dimond Street. Lasting damage is very rare when a vehicle is stopped quickly, and the drain and flush-through that still come first deal with it.
Pembroke Dock motorists and that petrol in a diesel myths they hear
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 that guidance — 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." Protection counts more on current diesels, not less, because their fuel runs through smaller parts at higher pressure.
Myth: "If it starts and drives, there is no harm done." This is the one that fools people. A petrol engine fed diesel generally won't run, so the motorist stops and the damage 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 wears. Being able to run is not the same as being fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct issue. It does not put back what petrol has thinned, and the petrol is still in the tank later.
Myth: "Drain that tank yourself and you're sorted." After the engine has been run, some of that petrol is no longer in that tank: it's in the filter and the lines, and it goes straight back through the pump on the next start. It's also really risky to drain petrol into a can at the kerbside.
Why petrol in a diesel takes place so easily
No one does it on purpose, and it's rarely carelessness. The petrol nozzle is the smaller of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol vehicle at all. The forecourt makes it easy, and the mistake runs one way.
Habit and the car getting out of step is how it happens. A new vehicle, a hire car or a courtesy car. Two cars on one driveway, one petrol, one diesel. A forecourt you know, only with its pumps laid out differently. A rushed fill en route to the nearest station with a train to catch. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that's when. With rain, a call arriving, or children to deal with, the hand just does what it has always done.
Next time you fill up in Pembroke Dock: preventing petrol in a diesel
- 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.
- Plenty of cars state the fuel inside the filler flap or on the cap, and so check there on the first fill in a motor you don't know.
- One of each in the household? Mark your key to your diesel — a coloured fob, a sticker — because intending to remember is not enough.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump. It seems silly and it does the trick.
- Whilst you are thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Add-on devices exist for vehicles without one, and some diesels come with a filler that won't take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Noticing it halfway? Stop there and then. A weaker mixture follows from less petrol inside your tank, but your next stage remains the same: do not fire it up.
Petrol already in a diesel around Pembroke Dock? Start here
Then the order of things is short. Starting it is out, and so is turning on the ignition. Yet on the forecourt, at Asda or anywhere else? Ask the staff to help you push it clear of the pump. What went in, roughly how much, and if it's run: tell us those when you ring 0333 366 0103.
Say so if it was AdBlue instead of petrol: it is a different issue, with its own page for Pembroke Dock, because AdBlue brings corrosion and deposits rather than lost protection.
One petrol in a diesel job around Pembroke Dock costs more than another. Why?
Four different tasks lie behind the four situations above — which is why there is no honest single quote. The scenario itself does most of the work of moving the cost. Two things come after that: the petrol that got in as a proportion of what your tank takes, then the place the vehicle is in and whether our van can get to it safely.
Three questions come first, before any quote, instead of after — what got in, how much, has it run — and that is the reason. A range becomes a straight figure when those answers are in.
About Pembroke Dock
Pembroke Dock is a coastal town situated in the county of Pembrokeshire, Wales. It is located near the River Cleddau, which provides a natural harbour. The town is positioned close to Pembroke, with which it has strong historical and geographical ties. Pembroke Dock is characterised by its maritime heritage and coastal setting.
Across Pembrokeshire and around Pembroke Dock: fuel drain cover
Llanion, Waterloo and Pembroke Ferry are among the places around Pembroke Dock that the same teams work, answering petrol in diesel call-outs across Pembroke Dock's SA postcode area. We drain where your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Pembroke Dock: still at the pump?
The best position there is, then — that is where you are. Keep the vehicle switched off, then ring.