Petrol in a Diesel Car in Nup End: How Worried Should You Be?
If it has not been started, you can worry less than you probably are. Until your ignition primes your pump, your starter cranks, or your car is driven, petrol in a diesel tank simply sits there and does nothing. Which means the truthful reply to that first Nup End question — "have I ruined it?" — normally no. To keep the vehicle that way, phone Petrol in Diesel then leave your engine alone. The rest of this page explains what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
Your engine and petrol in a diesel: what goes on
Two tasks fall to diesel on its route round a motor. It combusts, and before it burns it protects. Very fine clearances are built into the fuel injectors and your high-pressure pump, and only the diesel running through stops their surfaces grinding together.
The second task petrol doesn't do at all, and the first it does badly. It's thinner than diesel and takes away the protection the fuel system depends on, so a pump running on a petrol mix is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the knocking comes from.
The shape of the problem is plain when you put those together. Not contact but movement is what does the damage. Where the petrol is only in your tank, it's a problem of fuel, nothing more. Whatever a worn pump sheds travels on, carried by your fuel, into your injectors downstream, which is why a pump that has worked on that petrol is where a mechanical problem starts.
Four scenarios our engineers see around Nup End: how bad is petrol in a diesel?
Filled up, never started. The best case there is. At a forecourt, and really only there, that petrol is still limited to your tank — because anywhere else your car was driven to get to it. The job is emptying and rinsing on the spot.
Started for a moment, or only the ignition on. Once primed, the system has pulled petrol from that tank up to the fuel filter and your lines. Still normally easy: drain, flush, and the fuel filter sorted.
Driven a couple of miles. Now the pump has spent those miles working on diluted fuel. How hard the vehicle was driven counts as much as how far, and the work takes in that tank, the fuel lines, the fuel filter and fresh fuel through the whole system. Driving the children to Wingrave Church of England Combined School is one sort of trip. A run as far as Milton Keynes, under 15 miles away, is a very different job. So is any mileage on the M1, under 15 miles from Nup End, where your engine has been working hard the whole time.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. That's the motor telling you its fuel has stopped acting like diesel. Pull up on the spot — on the verge on Abbotts Way, at the kerb, down a side road — and do not move it. A car stopped soon very rarely has long-term damage, as the fuel drain and the flush-through, which still come first, sort it out.
Nup End people and the petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a fuller tank, still the same mixture. Percentage is not how a diesel fuel system tolerates petrol, however much that guidance presumes.
If anything, the reverse is true. Myth: "A modern diesel can cope with a bit of petrol." At higher pressure, through smaller parts: that is how a modern diesel moves its fuel, so the protection counts more, not less.
"It starts, it drives, so there is no harm" — the myth that trips up more drivers than any other. The motorist of a petrol motor fed diesel normally stops, since it will not run, and the harm stops with them. Whilst the pump grinds, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. Being able to run is not proof of being fine.
An old fix for a separate issue lies behind this one. Myth: "Add some two-stroke oil and drive the car home." What petrol has diluted remains thinned, and the petrol stays inside your tank anyway.
Myth: "Drain that tank yourself and you are sorted." Once your engine has been run, some of the petrol is no longer in your tank: it's in the fuel filter and your lines, and it goes right back through your pump at your next start. It's also really hazardous to drain petrol into a can by the roadside.
How it happens: petrol in a diesel
A careless moment is rarely the cause, and no one means to do it. A diesel nozzle generally won't go into a petrol car, yet the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error easy, and just in that direction.
It takes place when routine and your car stop matching. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. Your normal forecourt, its pumps suddenly in a different order. A train to catch, and a hurried fill en route to Cheddington. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that is when. Add rain, a phone call or a back seat full of kids, and the hand repeats what it has always done.
How to prevent petrol in a diesel at your next fill-up in Nup End
- The label is what counts, and so check the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, yet not on each forecourt.
- Check the filler flap. Many cars state the fuel type inside the flap or on the cap. Look at it on the first fill in a car you don't know.
- One of each in the home? Mark the key to your diesel — a coloured fob, a sticker — because intending to remember isn't enough.
- 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 sounds silly and it works.
- Thinking about something else is when this becomes an easy mistake to make, so tuck your phone away and 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 exist for cars without one. They are a backstop, not a reason to stop checking the petrol pump.
- Less petrol makes a weaker blend, so stop the moment you notice — while remembering that your next step is unchanged. It's still not to fire it up.
Put petrol in a diesel in Nup End already?
Short and simple, then, is the order of things. Leave it unstarted, with your ignition switched off as well. The staff on the forecourt — whether at Gulf itself or wherever you filled up — will normally help push it away from the pump if you ask. Then call 0333 366 0103 and tell us what got in, roughly how much, and if it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a separate fault — Nup End has a page just for it.
What makes one Nup End petrol in a diesel job cost more than the next
Four separate tasks sit behind the four scenarios above — which is why there's no fair single quote. Which of them you are in is mostly what moves your cost. The ratio counts next, meaning how much of that tank is petrol, and then the location of the car and whether reaching it is safe for our van.
Before any quote, not after, we ask three questions: your fuel that got in, its amount, and whether it's run. That's why. With the replies, you get a straight figure instead of a range.
About Nup End itself
Nup End is a suburban area in Buckinghamshire, situated inland at an elevation of around 130 metres. Nup End lies near the villages of Wingrave, Aston Abbotts, and Rowsham, and is approximately 12 miles from Milton Keynes. Nup End is characterized by its predominantly detached housing stock, and is home to around 1106 residents. Nup End is also within commuting distance of London, being around 36 miles from the capital.
Fuel drain cover across Buckinghamshire, Nup End included
Nup End waits in the HP postcode area, and our vans that answer petrol in diesel jobs there work the spots around it as well — Wingrave, Aston Abbotts and Rowsham among them. No need to bring the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places where we work.
Still at the pump in Nup End?
The best position there is, then — that's where you are. Keep it off. Ring.