How Worried Should You Be? Petrol in a Diesel Car in Fishponds
Unstarted? Then less anxious than you probably feel. Everyone in Fishponds begins with "have I wrecked it?", and the honest answer is usually no: petrol left inside the tank of any diesel remains harmless until priming, cranking or driving draws it into the fuel system. Keep it that way: leave your engine off and call 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 never do it again.
What petrol in a diesel does to your engine
Two tasks fall to diesel on its route through a motor. Before it ignites, it protects — and then it ignites. Extremely fine tolerances go into your injectors and the high-pressure fuel pump, and just the diesel flowing through keeps their surfaces from grinding together.
Of these two jobs, petrol manages the first poorly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump running on that mixture wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the rattling.
Together, those make the shape of the problem clear. It's circulation that causes the harm, not contact. All a tank with petrol in it amounts to is a fuel fault. Once your pump has been working on that petrol, a mechanical issue has begun: whatever is shed by a pump that's grinding is carried downstream to the fuel injectors with your fuel.
Fishponds, petrol in a diesel: four cases, from mild to serious
Fuelled but not once started — the best it gets. The petrol is inside that tank and only that tank, and the task is a drain and a flush where the vehicle sits. This is the one situation that can only truly occur at a forecourt, as anywhere else the vehicle has been driven to get there.
A brief spell of running, or merely the ignition on. The system has been bled, so petrol has left the tank and reached the fuel filter and your lines. Still usually easy: drain, flush, and your filter seen to.
Your pump has spent a few miles on weakened fuel — that is what driving it meant. How hard the vehicle was driven counts as much as how far, and the work takes in your tank, the lines, your filter and clean fuel through the entire circuit. Driving the children to Avanti Gardens School is one sort of trip. Driving as far as Bristol, under 5 miles away, makes a very different job — as does any miles on the M32, under a mile from Fishponds, with the engine running hard all the way.
Driven on till it protested — clattering, smoke, an uneven idle, a dead throttle. That's your motor telling you its fuel has stopped behaving like diesel. Stop where you are — on the verge on Fishponds Road, at the kerb, down a side road — and do not move it again. What comes first is still the fuel drain and flush, and that deals with it, with permanent damage very uncommon if a vehicle is pulled over quickly.
Fishponds motorists and the petrol in a diesel myths they hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up removes nothing; it gives you a bigger tank of the same mixture. That guidance assumes a diesel fuel system handles petrol by percentage. It does not.
Myth: a modern diesel copes with a bit of petrol. If anything, the opposite. Lubrication matters more on newer diesels, not less, because their fuel passes through smaller parts at higher pressure.
This is the one that catches motorists. Myth: "If it starts and drives, there's no damage done." Diesel in a petrol motor usually leaves a motor that won't run: the driver stops, and so does the harm. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile your pump wears. Running isn't the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old fix, meant for another problem. It does not put back what petrol has diluted, and the petrol is still inside that tank later.
Once the motor has been run, part of the petrol is in the filter and your lines, not the tank — and the next start pulls it right back through your pump. So the myth "drain the tank yourself and you are sorted" does not hold. Also, a can of petrol drained by the roadside is genuinely risky.
Why petrol in a diesel happens at all
It's rarely carelessness, and no one does it on purpose. The petrol nozzle is the narrower of the two and slips 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 simple, and the mistake runs one way.
It happens when habit and your car stop matching. Any motor that's new to you — hired, on loan as a courtesy car, or just bought. Two cars on one drive, one petrol, one diesel. The pumps in a different order on a familiar forecourt. Rushing for a train outside Stapleton Road and fuelling up en route. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it has always done.
Fishponds drivers: how to prevent petrol in a diesel next time
- A green handle for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Go by the label on the petrol pump, not the colour.
- The first fill in an unfamiliar car is the time to check the filler flap — on it, or on the cap, many cars state which fuel to use.
- Good intentions do less than a sticker or a fob in a bright colour on your diesel's key if a household has one of each. So mark it.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car needs its first tank. It sounds silly. It works.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away then keep your mind on the pump.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to refuse a petrol nozzle, and add-on devices exist for the remainder. Treat it as a safety net, then keep reading the petrol pump.
- Stop as soon as you realise. Less petrol inside the tank means a weaker blend. It does not change what to do next, which is still not to start it.
Already put petrol in a diesel in Fishponds?
The order of things is brief, then. Leave it unstarted, with your ignition off too. Yet on the forecourt, at Morrisons or anywhere else? Ask the staff to help you roll the vehicle away from the pump. What got 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 different problem — corrosion and deposits instead of lost lubrication — and it has its own page for Fishponds.
Why one petrol in a diesel job around Fishponds costs more than another
The four situations above are four separate tasks, so no single quote for this would be honest. Which of them you are in is mostly what shifts the cost. Two things come after that: the petrol that was put in as a share of what the tank holds, then the place the vehicle is in and whether our van can reach it safely.
Before any quote, not after, we ask three queries: your fuel that got in, the volume, and whether it has run. That is why. Their answers are what change a range into one firm number.
About Fishponds and its setting
Fishponds is a locality situated inland, approximately 3.7 miles from Bristol city centre, with an elevation of around 61 metres. Fishponds is characterised by its semi-detached housing stock and is located near several local amenities, including Mayfield Park. Fishponds forms part of the larger Bristol urban area, with easy access to the city's facilities. Fishponds has a population of around 5334 residents.
Across Bristol and around Fishponds: fuel drain cover
Fishponds rests in the BS postcode area, and our vans that answer petrol in diesel call-outs there work the locations near it as well — Mayfield Park, Hillfields and Ridgeway among them. The vehicle does not need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Fishponds and still at the petrol pump?
The best spot there is, then — that is where you are. Leave the car switched off, then ring.