Petrol in a Diesel Car in Newbridge: How Worried Should You Be?
Far less than you likely are, provided it hasn't been started. "Have I ruined it?" is the first thing anyone in Newbridge asks, and the honest answer is usually no, since petrol left in a diesel tank harms nothing till it's dragged through the system — by ignition priming, by the starter, or by being driven. Keep it like that: leave the engine off and phone Petrol in Diesel. The rest of this page covers what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you a second time.
Petrol in a diesel: what does it do to the motor?
Two jobs fall to diesel on its route round a motor. Before it combusts, it lubricates — and then it combusts. What stops the surfaces inside your high-pressure pump and the fuel injectors from wearing against each other is your diesel passing through them — they're designed to extremely fine clearances.
The second task petrol doesn't do at all, and the first it does poorly. The rattling comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips out the protection your system rests on, and any pump working on that mix is wearing itself.
Together, those leave the shape of the problem clear. The damage is done by circulation, not by contact. All a tank with petrol in it amounts to is a fuel problem. The beginning of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds moves on with your fuel to your injectors beyond it.
Four situations our technicians see around Newbridge: how bad is petrol in a diesel?
The best case there can be: filled up, never started. That petrol is inside the tank and only that tank, and the task is a drain and a flush where the vehicle stands. This is the one situation that can only truly happen on a forecourt, as anywhere else the vehicle has been driven to get there.
Started for a second, or just the ignition on. Your system has been primed, and so petrol has left that tank and reached the filter and the fuel lines. Normally little more than clearing, rinsing and sorting the fuel filter, so still straightforward.
Your pump has spent a few miles on diluted fuel — that's what driving the car meant. The work is that tank, the fuel lines, the filter and clean fuel through the entire system, and how hard the car was driven counts as much as how far. Driving the kids to Newbridge Primary School is one sort of trip. Very different once more: a run to Bath, under 3 miles away, or any distance on the M4, under 10 miles from Newbridge, where the engine kept working hard.
Driven until it complained. Clattering, a lumpy idle, smoke, a throttle that has gone soft. What you are hearing is the engine signalling fuel that no longer behaves like diesel. Whether it is the verge on Brassmill Lane, a lay-by or a side road, stop there and leave it. Long-term damage is very uncommon when a vehicle is pulled over early, and the drain and flush-through that still come first sort it out.
Petrol in a diesel myths Newbridge people hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance presumes.
"Newer diesels can handle a little petrol" — a myth, and closer to the reverse. At higher pressure, through finer parts: that is how a modern diesel handles its fuel, so the lubrication matters more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools people. Any petrol motor fed diesel normally will not run, so the motorist stops and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile the pump grinds. Running isn't the same as fine.
Myth: a two-stroke additive lets you to drive home. It is an old workaround, meant for another issue. What petrol has thinned remains weakened, and the petrol remains inside the tank anyway.
Myth: "Drain the tank yourself and you are sorted." After your engine has been run, some of the petrol is no longer inside your tank: it is in the fuel filter and the fuel lines, and it goes straight back through the pump at the next start. Also, a can of petrol drained at the roadside is truly dangerous.
How petrol ends up: petrol in a diesel
On purpose? Never. Through carelessness? Rarely, if ever. The petrol nozzle is the slimmer of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol vehicle at all. The forecourt makes it easy, and the mistake runs one way.
Routine and the vehicle falling out of step is when it occurs. Hire cars, courtesy cars, and vehicles that are new to you. A household with one petrol and one diesel on the driveway. A well-known forecourt with the pumps in a different order. A train to catch, and a hurried fill on the way to Oldfield Park. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it takes place. With rain, a call coming in, or a car full of children to deal with, the hand simply does what it has always done.
Preventing petrol in a diesel next time you fill up in Newbridge
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Check the petrol pump's label; the colour is just a clue.
- Plenty of vehicles state the fuel inside your filler flap or on the cap, and so check it on your first fill in a car you do not know.
- Good intentions count for less than a sticker or a fob in a bright colour on the diesel's key if a home has one of each. So label it.
- 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 seems silly and it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away then keep your mind on the petrol pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to block a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop checking the petrol pump.
- Stop the moment you realise. Less petrol inside your tank makes a weaker mix. It does not change what to do next, which is still not to fire it up.
Put petrol in a diesel in Newbridge already?
Then, there's only a short order of things. Starting it is out, and so is switching on the ignition. If you're still on the forecourt — Gulf or anywhere else — ask the attendants to help you roll the car away from the pump. What was put in, roughly how much, and whether it's run: tell us those when you call 0333 366 0103.
If it was AdBlue rather than petrol, say so. That is a separate issue — corrosion and deposits rather than lost lubrication — and it has its own page for Newbridge.
What makes one Newbridge petrol in a diesel task cost more than the next
There's no honest single price for this, because the four scenarios above are four different tasks. Which of them you are in is chiefly what shifts your cost. Where the vehicle is counts too, and whether a van can safely reach it, after the ratio of petrol to what your tank holds.
Before any quote, not after, we ask three questions: your fuel that got in, the amount, and whether it has run. That is why. Those replies are what change a range into one firm number.
About Newbridge, for a moment
Newbridge is a suburban area in Somerset, situated on the River Avon, with a mix of semi-detached housing and other residential properties. Newbridge lies close to the city of Bath, being only 1.9 miles away, and is near other local areas such as Twerton and Combe Park. Newbridge has a population of around 3519 people and is located at an elevation of 21 metres above sea level. Newbridge is also relatively close to major cities, with London being approximately 98.3 miles away.
Newbridge and Somerset: where our fuel drain cover runs
Newbridge rests in the BA postcode area, and the vans that answer petrol in diesel call-outs there work the locations around it as well — Twerton, Combe Park and Lower Weston among them. No need to bring your car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all locations where we work.
Still at the petrol pump in Newbridge?
Then you're in the best place there is. Keep it off. Phone.