Petrol in a Diesel Car in Potterne: How Worried Should You Be?
Far less than you probably are, if it hasn't been started. Everyone around Potterne begins with "have I wrecked it?", and the fair answer is generally no: petrol resting inside that tank of any diesel stays harmless till priming, cranking or driving pulls it into your fuel system. Keep it that way: leave the engine off and ring Petrol in Diesel. What petrol actually does to a diesel, how to gauge how far it's gone, and how to keep it from happening a second time: that is the rest of this page.
Petrol in a diesel: what does it do to the engine?
Two jobs fall to diesel on its journey through a motor. It ignites, and before it combusts it lubricates. Made to extremely fine clearances, your injectors and the pump rely on your diesel moving through them to stop their surfaces wearing against one another.
Petrol does the first job badly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump running on the blend to wear itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the clattering.
Together, those leave the shape of the problem clear. The harm is done by circulation, not by contact. Petrol in the tank is a fuel issue. Once the pump has been running on that petrol, a mechanical issue has begun: whatever is shed by a pump that's wearing travels onward to the fuel injectors with the fuel.
How bad is petrol in a diesel? Four situations our technicians see in Potterne
Filled but not once started — the best it gets. On a forecourt, and really only there, the petrol is still confined to that tank — since anywhere else your car was driven to reach it. The job is emptying and rinsing on the spot.
The ignition switched on, or a brief start. Once primed, your system has drawn petrol out of your tank as far as the fuel filter and your lines. That's normally still an easy job — a drain, a flush, and the filter seen to.
Driven a few miles. Now the pump has spent these miles working on diluted fuel. The work is your tank, the fuel lines, your filter and clean fuel through the entire circuit, and how hard your car was driven counts as much as how far. On the school run to Wansdyke School, the distance is short. A run as far as Bath, under 25 miles away, is a very different task. So is any miles on the M4, under 15 miles from Potterne, where the motor has been running hard throughout.
Driven until it protested. Rattling, a lumpy idle, smoke, a throttle that has gone soft. That is your engine telling you its fuel no longer is behaving like diesel. Stop on the spot — on the verge on Mill Road, at the kerb, down a side road — and do not move it. A car pulled over quickly very seldom has long-term damage, as the drain and the flush-through, which still go first, take care of it.
Myths Potterne people hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A fuller tank of the same mixture is all you get, because topping up takes out nothing. A diesel fuel system doesn't accept petrol by percentage in the way that guidance presumes.
"Current diesels can handle a little petrol" — a myth, and closer to the reverse. Lubrication counts more on current diesels, not less, because their fuel runs through more precise parts at higher pressure.
"It starts, it drives, so there is no harm" — the myth that catches more people than any other. The motorist of a petrol motor fed diesel usually has no choice but to stop, because it will not run, and the harm stops there. While your pump wears, a diesel fed petrol usually starts, idles and drives away as though nothing has happened. Running is not the same as fine.
Myth: a two-stroke additive lets you to drive home. It was an old workaround, meant for another fault. None of what petrol weakened gets put back by it — and later, the tank still holds that petrol.
If your engine has run, part of that petrol sits in the fuel filter and your lines, not the tank — and your next start sends it right back through your pump. So the myth "drain that tank yourself and you are sorted" doesn't hold. It's also genuinely risky to drain petrol into a can by the roadside.
How it happens: petrol in a diesel
It's rarely carelessness, and no one does it on purpose. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle mostly will not go into a petrol motor at all. So the slip runs one way.
Routine and the car falling out of step is how it takes place. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. The pumps in a different order on a familiar forecourt. Filling up in a rush on the way to Melksham, with a train to catch. Precisely the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Tiguan for the first time. Add rain, a phone call or a back seat full of children, and the hand does what it has always done.
Preventing petrol in a diesel next time you fill up around Potterne
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Read the pump's label; the colour is only a hint.
- The first fill in an unfamiliar motor is the time to check the filler flap — on it, or on the cap, plenty of vehicles state the fuel to use.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key when a household has one of each. So label it.
- 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 daft and it does the trick.
- Mistakes like this are simple to make whilst your mind is on something else, and so your phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to refuse a petrol nozzle, and aftermarket devices are available for the remainder. Treat it as a backstop, then keep checking the petrol pump.
- Stop as soon as you notice. Less petrol in the tank makes a weaker blend. It doesn't change what to do next, which is still not to fire it up.
Already put petrol in a diesel in Potterne?
Then, there is only a short order of things. Don't switch your ignition on, and do not fire it up. Yet on the forecourt, at Murco or anywhere else? Ask the staff to help you push the car away from the pump. Phone 0333 366 0103 next, with three facts — your fuel, the rough amount, and whether it has run.
Corrosion and deposits are the problem with AdBlue, where petrol brings lost lubrication. So if it was AdBlue, say so — and read its own Potterne page.
Potterne petrol in a diesel jobs: why one costs more than another
The four scenarios above are four separate jobs, so no single price for this would be fair. The situation itself does most of the work of moving your cost. Two things follow that: the petrol that got in as a share of what that tank holds, then the spot your car is in and whether a technician can get to it safely.
Before any quote, not after, we ask three questions: your fuel that went in, its quantity, and whether it's run. That's why. With the replies, you get a straight figure instead of a range.
About Potterne
Potterne is a village in Wiltshire, situated inland at an elevation of 87 metres, approximately 15 miles from the city of Bath. Potterne has a population of around 1543 people and is characterised by predominantly detached housing. Potterne is located near several other small settlements, including Potterne Wick, Worton, and Poulshot, in the South West region of England. Potterne is about 82 miles west of London, making it a rural community with some commuter links to the capital.
Fuel drain cover around Potterne and across Wiltshire
Potterne rests in the SN postcode area, and our teams that answer petrol in diesel call-outs there work the locations around it as well — Potterne Wick, Worton and Poulshot among them. The vehicle does not need to move to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Potterne: still at the petrol pump?
In that case, you couldn't be in a better position. Switched off it remains; then ring.