How Worried Should You Be? Petrol in a Diesel Car in Nob End
Not started? Then less worried than you likely are. Until your ignition primes your pump, your starter turns, or your car is driven, petrol in a diesel tank just rests there and does no harm. Which means the honest reply to the first Nob End query — "have I wrecked it?" — usually no. Petrol in Diesel is who to phone, with your engine kept off, and so it remains that way. What petrol really does to a diesel, how to judge how far it has gone, and how to stop it from happening a second time: that's the rest of this page.
Petrol in a diesel: what does it do to your engine?
Passing through a motor, diesel is doing two jobs at the same time. It protects first, and after that does it burn. Very fine tolerances are built into the injectors and the high-pressure pump, and only your diesel running through keeps their surfaces from grinding together.
Petrol does the first task badly and the second not at all. It's thinner than diesel and takes away the lubrication the system rests on, and so a pump running on a petrol mix is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the rattling comes from.
Put those together and the shape of the issue is plain. The harm is done by circulation, not by contact. Where that petrol is only in the tank, it is a fault of fuel, nothing more. Once your pump has been running on that petrol, a mechanical issue has begun: whatever is shed by a pump that's wearing down is carried downstream to your injectors with the fuel.
Nob End, petrol in a diesel: four cases, from mild to major
The best case there is: filled up, never started. Being at a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With the petrol held in the tank alone, it is cleared and rinsed right where it stands, and nothing more is needed.
The ignition switched on, or a brief start. The system has been primed, and so petrol has left the tank and reached your filter and the fuel lines. Usually little more than clearing, cleaning and sorting the fuel filter, so still straightforward.
Driven a couple of miles. Now the pump has spent these miles labouring on diluted fuel. Tank, lines, filter, then fresh fuel run through the whole system: that is this work, and the way the vehicle was driven matters as much as the mileage. On the school run to Mytham Primary School, the distance is small. Very different a second time: a trip to Salford, under 10 miles away, or some distance on the Kearsley Spur, under a mile from Nob End, where the motor never stopped working hard.
Driven on till it protested — knocking, smoke, a ragged idle, a soft throttle. What you are hearing is your motor reporting fuel that no longer runs like diesel. Leave it where it has stopped: a lay-by, a side street, the verge on Newmarket Road. The fuel drain and flush still come first, and they sort it out: if a car is pulled over soon, long-term damage is very rare.
Myths Nob End motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you are left with a fuller tank, still the same mix. A diesel fuel system doesn't accept petrol by percentage in the way that guidance assumes.
If anything, the opposite is true. Myth: "A newer diesel can cope with a bit of petrol." A current diesel runs its fuel through smaller parts at higher pressure, which makes the lubrication matter more, not less.
The myth that catches motorists out: if it starts and drives, it must be unharmed. The driver of a petrol engine fed diesel usually has no choice but to stop, since it will not run, and the damage stops with them. Whilst the pump grinds, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Running does not mean fine.
An outdated workaround for a separate issue lies behind this one. Myth: "Add some two-stroke oil and drive it home." It does not put back what petrol has weakened, and the petrol is still in the tank later on.
"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 right back through your pump on your next start. Draining petrol into a can by the kerbside is also truly risky.
Petrol in a diesel: how does it take place?
Carelessness is seldom the cause, and nobody means to do it. One way only, because of the nozzles: the smaller petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one mostly will not fit a petrol car. That's how the forecourt makes it easy.
When habit and your car stop matching, it happens. A new car, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. A forecourt you know, but with its pumps arranged differently. Rushing for a train outside Farnworth and fuelling up en route. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist accustomed to petrol: precisely when it takes place. Add rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
Next time you fill up around Nob End: preventing petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, yet not on each forecourt. The label is what matters.
- Check the filler flap. Many motors state the fuel type inside the flap or on the cap. Look at it on the first fill in any car you don't know.
- One of each in the house? Mark the key to the diesel — a bright fob, a sticker — because meaning to remember isn't enough.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car gets its first tank. It sounds silly. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away then keep your mind on the 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 cars without one. They are a backstop, not a reason to stop checking the pump.
- Stop the moment you realise. Less petrol inside that tank means a thinner mixture. It doesn't change what to do next, which is still not to fire it up.
Put petrol in a diesel around Nob End already?
Then, there's just a short order of things. Do not turn your ignition on, and do not crank it. The staff at the forecourt — whether at Gulf itself or wherever you filled up — will normally help push it clear of the petrol pump if you ask. Ring 0333 366 0103 next, with three facts — your fuel, the approximate quantity, and if it has run.
Say so if it was AdBlue rather than petrol: it is a different problem, with its own page for Nob End, since AdBlue brings corrosion and deposits instead of lost lubrication.
Nob End petrol in a diesel jobs: why one costs more than another
There is no fair single quote for this, since the four scenarios above are four different tasks. Which of them you are in is chiefly what moves your cost. Two things come after that: the petrol that went in as a share of what the tank holds, then the spot your car is in and whether a technician can get to it safely.
What went in, how much, and whether it has run — three queries we ask before pricing, not after, for precisely that reason. Those replies are what change a range into one firm number.
About Nob End and its setting
Nob End is a suburban area in Greater Manchester, situated on the riverside at an elevation of around 85 metres. Nob End lies near the cities of Salford and Manchester, with nearby places including Little Lever, Prestolee, and Dove Bank. Nob End has a population of approximately 3548 people, predominantly living in semi-detached housing. Nob End is located about 6.2 miles from Salford and 170.2 miles from London.
Fuel drain cover across Greater Manchester, Nob End included
Nob End rests in the BL postcode area, and our teams that answer petrol in diesel jobs there work the locations around it as well — Little Lever, Prestolee and Dove Bank among them. The vehicle does not need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Nob End: still at the petrol pump?
In that case, you couldn't be in a better spot. Keep it off. Phone.