Colerne: Petrol in a Diesel Car? How Worried to Be
Probably less than you already are — as long as nobody has started the car. "Have I ruined it?" is the first question everyone around Colerne asks, and the honest answer is generally no, because petrol resting in a diesel tank harms nothing until it's dragged through your fuel system — by ignition priming, by your starter, or by driving. Keep it like that: leave your engine off and ring Petrol in Diesel. Keep reading for three things: the effect petrol has inside a diesel motor, the signs of how far it has spread, and ways to make sure you don't do it again.
Your engine and petrol in a diesel: what happens
Diesel has two tasks on its way through an engine. Oiling comes before burning; it does both. Extremely fine clearances are built into the fuel injectors and the high-pressure fuel pump, and just the diesel flowing through stops their surfaces grinding together.
The second job petrol does not do at all, and the first it does poorly. A pump running on a petrol mixture is wearing itself out, because petrol is thinner than diesel and strips out the lubrication your fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where the clattering comes.
Combined, those leave the shape of the problem clear. The damage is done by circulation, not by contact. Petrol in a tank is a fuel issue. Once your pump has been labouring on that petrol, a mechanical issue has started: anything shed by a pump that's grinding travels onward to the fuel injectors with your fuel.
Petrol in a diesel around Colerne: how serious is it? Four cases
Fuelled, and not started: nothing beats it. Being on a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol kept in the tank alone, it is emptied and purged on the spot, and nothing more is needed.
Your ignition turned on, or a short start. Petrol has come out of your tank and reached the filter and your lines, because the fuel system has been primed. Still usually easy: drain, flush, and the fuel filter seen to.
Driven a couple of miles. Now your pump has spent those miles running on weakened fuel. How hard your car was driven matters as much as how far, and the work takes in the tank, the lines, your filter and fresh fuel through the entire system. Driving the kids to Colerne CofE Primary School is one sort of trip. Any distance on the M4, under 10 miles from Colerne, means your engine working hard throughout, and a run to Bath, under 10 miles away, is a very different task too.
Rattling, an uneven idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you the fuel is no longer acting like diesel. Whether it is the verge on High Street, a lay-by or a side street, stop there then leave it. What goes first is still the drain and flush, and that sorts it out, with permanent damage very unusual when a vehicle is pulled over soon.
What Colerne people get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Topping up takes out nothing; it gives you a fuller tank of the same mixture. A diesel fuel system doesn't accept petrol by percentage in the way that guidance supposes.
"Current diesels can handle a little petrol" — a myth, and nearer the reverse. A modern diesel runs its fuel through more precise parts at higher pressure, which makes the lubrication count more, not less.
"It starts, it drives, so there is no harm" — the myth that catches more drivers than any other. The driver of a petrol engine fed diesel usually has no choice but to stop, because it will not run, and the damage stops with them. While your pump grinds, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Running doesn't mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an outdated fix for a different fault. What petrol has thinned remains diluted, and the petrol stays inside the tank anyway.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol lies in the fuel filter and lines, ready to go straight back through the pump at the next start. And, a can of petrol drained by the roadside is truly hazardous.
Petrol in a diesel: how does it happen?
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle generally will not fit a petrol motor, but the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake easy, and only in one direction.
The moment routine stops matching the car is the moment it happens. Courtesy car, hire car, or a motor that's brand new. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. Racing for a train at Bath Spa and fuelling up en route. The first fill-up in a diesel Volkswagen Tiguan after years of driving petrol is exactly the moment it occurs. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
Next time you fill up in Colerne: preventing petrol in a diesel
- Read the pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on each forecourt. The label is what counts.
- In a motor you don't know, look inside the flap over your filler or at the cap before the first fill: plenty of motors print the fuel type there.
- One of each in the home? Mark the key to the diesel — a bright fob, a sticker — since intending to remember isn't 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 pump. It sounds silly and it works.
- Put the phone away. This is an easy mistake to make whilst you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to refuse a petrol nozzle, and aftermarket devices exist for the remainder. Count it as a backstop, and keep reading the pump.
- Less petrol makes a thinner blend, so stop as soon as you realise — though remembering that the next step is unchanged. It's still not to fire it up.
Petrol already in a diesel around Colerne? Start here
Short and simple, then, is the order of things. Leave it unstarted, with the ignition switched off too. If you're still at the forecourt — Shell or anywhere else — ask the staff to help you roll it clear of the pump. What got in, roughly how much, and if it has run: tell us those when you call 0333 366 0103.
If it was AdBlue and not petrol, say so. That's a separate issue — corrosion and deposits rather than lost protection — and it has its own page for Colerne.
Why one petrol in a diesel job around Colerne costs more than another
A fair single price doesn't exist here: four scenarios, four separate tasks. Which of them you're in is chiefly what moves your cost. Two things follow that: the petrol that went in as a proportion of what your tank takes, then the place the vehicle is in and whether a van can get to it safely.
What was put in, how much, and if it's run — three queries our technicians ask before pricing, not after, for exactly that reason. Given the replies, there is a straight figure rather than a range.
About Colerne, for a moment
Colerne is a village in Wiltshire, situated on the banks of the River Avon, with a mix of semi-detached housing and other types of homes. Colerne sits at an elevation of 164 metres, near the city of Bath, and is surrounded by nearby places such as Eastrip, Thickwood, and Ditteridge. Colerne has a population of approximately 985 residents, and its location near Bath makes it a desirable place to live. Colerne is also relatively close to London, being around 92 miles away.
Across Wiltshire and around Colerne: fuel drain cover
Colerne rests in the SN postcode area, and our teams that answer petrol in diesel call-outs there work the locations near it as well — Eastrip, Thickwood and Ditteridge among them. Our technicians drain wherever the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Still at the pump in Colerne?
Then you are in the best position there can be. Turned off it stays; then phone.