Petrol in a Diesel Car in Polmont: How Worried Should You Be?
Unstarted? Then less worried than you likely are. Petrol resting in a diesel tank does nothing to the 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 around Polmont asks, "have I wrecked it?", is usually no. Leave your engine off and call Petrol in Diesel — that keeps it like that. Keep reading for three things: the effect petrol has inside a diesel motor, the clues of how far it has spread, and the way to make sure you never repeat it.
Petrol in a diesel: what does it do to the motor?
Diesel has two tasks on its way through a motor. It protects to begin with, and after that does it burn. Your high-pressure pump and the injectors are built to very fine clearances, and the diesel passing through them is what stops those surfaces from wearing down against each other.
The second task petrol doesn't do at all, and the first it does badly. A pump working on a petrol mix is wearing itself out, since petrol is runnier than diesel and strips out the lubrication the fuel system depends on. Petrol is also designed to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where any clattering starts.
The shape of the issue is clear once you put those together. Contact doesn't do the damage — circulation does. All a tank with petrol in it amounts to is a fuel problem. After your pump has been working on that petrol, a mechanical issue has begun: whatever is shed by a pump that's wearing down travels onward to your injectors with your fuel.
Four scenarios our engineers see in Polmont: how serious is petrol in a diesel?
Filled but never started — the best it gets. Being on a forecourt is what makes this the case: elsewhere, your car has been driven there to begin with. With the petrol held inside the tank alone, it is cleared and purged right where it stands, and nothing more is needed.
Your ignition turned on, or a short start. Your system has been primed, so petrol has left the tank and got to your filter and the fuel lines. Still generally easy: drain, flush, and the fuel filter dealt with.
Those few miles driven were your pump labouring on fuel thinned by petrol throughout. Tank, lines, filter, then clean fuel run through the whole system: that's this work, and the way the car was driven counts as much as the mileage. Short trips, such as the school run to the local primary school, are one thing. Getting as far as Dunfermline, under 15 miles away, makes a very different task — as does any miles on the M9, under a mile from Polmont, with the motor working hard all the way.
It protested, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone ragged. What you are hearing is your motor signalling fuel that no longer acts like diesel. Leave it where it stops: a lay-by, a quiet street, the verge on Main Street. Permanent damage is very unusual if a car is stopped quickly, and the fuel drain and flush-through that still come first sort it out.
Petrol in a diesel stories Polmont drivers hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." A bigger tank of the same mix is all you get, because topping up removes nothing. That advice assumes a diesel fuel system tolerates petrol by percentage. It doesn't.
Myth: a newer diesel copes with a bit of petrol. Rather, the opposite. Lubrication matters more on current diesels, not less, because their fuel passes through finer components at higher pressure.
One myth that catches drivers out: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it usually will not run, and so the motorist stops — and the damage stops with them. Feed petrol to a diesel and it generally starts, ticks over and pulls away as if nothing happened — all the while its pump wears. Running doesn't mean fine.
Myth: a two-stroke additive makes it safe to drive home. It was an old workaround, meant for another problem. None of what petrol weakened gets put back by it — and afterwards, the tank still holds that petrol.
"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 your pump on your next start. Also, a can of petrol drained at the roadside is genuinely hazardous.
How it happens: petrol in a diesel
A careless moment is rarely the cause, and nobody means to do it. One way only, since of the nozzles: the smaller petrol one slides inside a diesel filler with almost no resistance, while the diesel one mostly will not fit a petrol vehicle. That is how the forecourt makes it simple.
The moment habit stops matching the vehicle is the moment it happens. Hire cars, courtesy cars, and cars that are new to you. A household with one petrol and one diesel on the driveway. Your normal forecourt, its pumps now in a different order. A train to catch, and a hurried fill en route to the nearest station. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. Throw in a back seat full of kids, a phone call or rain, and habit takes over.
Preventing petrol in a diesel next time you fill up in Polmont
- The label is what counts, and so read the pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- Inspect the filler flap. Many vehicles state the fuel inside the flap or on the cap. Look at it on your first fill in any motor you do not know.
- Label your key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car needs its first tank. It seems silly. It does the trick.
- Whilst you're thinking about something else, this is an easy mistake to make — so put the phone away.
- Some diesels come with a filler designed to reject a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the petrol pump.
- Less petrol makes a thinner blend, and so stop the moment you realise — though remembering that the next step is unchanged. It is still not to start it.
Put petrol in a diesel in Polmont already?
Then the order of things is short. Starting it is out, and so is switching on your ignition. Ask the attendants to help you roll it clear of the pump if you're still at the forecourt, whether that is Esso or somewhere else. What went in, roughly how much, and whether it has run: tell us those when you call 0333 366 0103.
If it was AdBlue instead of petrol, say so. That's a separate issue — corrosion and deposits and not lost protection — and it has its own page for Polmont.
Why one petrol in a diesel task in Polmont costs more than another
There's no honest single price for this, because the four scenarios above are four different jobs. What moves the cost is mostly which of them you're in. Beyond that it is the proportion — how much petrol went in against how much that tank holds — and after that where the car is and whether a technician can reach it safely.
Before any quote, not after, come three queries: your fuel that got in, the quantity, and if it's run. That is why. Their replies are what change a range into one firm number.
About Polmont itself
Polmont is a village in Falkirk, situated near the coast at an elevation of 45 metres, with detached housing being the predominant type of accommodation. Polmont lies within commuting distance of several major towns, including Dunfermline, which is approximately 11 miles away. Polmont is surrounded by other small settlements, such as Old Polmont, Parkhill, and Wholeflats. Polmont has a population of around 1815 people, according to recent estimates.
Fuel drain cover around Polmont and across Falkirk
Our teams answering petrol in diesel jobs around Polmont, in the FK postcode area, equally work the spots around it, Old Polmont, Parkhill and Wholeflats among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians work, and the car does not need to move to us.
Still at the pump in Polmont?
Then, you couldn't be in a better place. Keep it off. Ring.