Should You Worry? Petrol in a Diesel Car in Norton Hill
Probably less than you are now — provided nobody has started the car. Everyone around Norton Hill begins with "have I ruined it?", and the honest answer is generally no: petrol left in the tank of a diesel remains harmless until priming, cranking or driving pulls it into your fuel system. Petrol in Diesel is who to ring, with the engine kept off, so it remains that way. What petrol actually does to a diesel, how to judge how far it's travelled, and how to stop it from happening again: that is the remainder of this page.
The engine and petrol in a diesel: what happens
Two tasks fall to diesel on its journey round a motor. It lubricates first, and after that does it burn. Very fine clearances go into the injectors and the high-pressure fuel pump, and just the diesel flowing through stops those surfaces grinding together.
The second task petrol doesn't do at all, and the first it does badly. It is runnier than diesel and strips away the lubrication the fuel system depends on, so a pump running on a petrol mixture 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's where the knocking comes from.
Put those together and the shape of the trouble is plain. The harm is done by circulation, not by contact. Any tank with petrol in it is a fuel fault. Whatever a worn pump sheds travels on, borne by your fuel, into the injectors further along, which is why a pump that has been working on that petrol is where a mechanical problem begins.
Four scenarios our technicians see around Norton Hill: how bad is petrol in a diesel?
Fuelled but not once started — the best it gets. Being on a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol kept in the tank alone, it is emptied and cleaned on the spot, and nothing more is needed.
A moment's running, or just the ignition on. Petrol has come out of the tank and got to the filter and your lines, because the fuel system has been primed. Still generally easy: drain, flush, and the fuel filter dealt with.
A couple of miles driven, and the pump has spent each of them running on weakened fuel. How hard the vehicle was driven counts as much as how far, and the work takes in that tank, your lines, the filter and clean fuel through the entire circuit. Driving the children to St Benedict's Catholic Primary School is one kind of trip. A run as far as Bath, under 10 miles away, is a very different job. So is any miles on the M32, under 15 miles from Norton Hill, where the engine has been labouring hard throughout.
Driven till it protested. Knocking, an uneven idle, smoke, a throttle that has gone soft. What you are hearing is the motor reporting fuel that no longer runs like diesel. Leave it wherever it has stopped: a lay-by, a side street, the verge on Charlton Road. Permanent damage is very unusual if a car is stopped soon, and the fuel drain and flush that still go first sort it out.
Norton Hill drivers and that petrol in a diesel stories 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 fuller tank of the same mixture. A diesel fuel system doesn't tolerate petrol by percentage in the way that advice presumes.
"Current diesels can handle a little petrol" — a myth, and closer to the reverse. Protection matters more on newer diesels, not less, since their fuel runs through smaller parts at higher pressure.
One myth that catches people off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol motor and it normally won't run, and so the motorist stops — and the harm stops with them. A diesel fed petrol usually starts, idles and drives away as if nothing has happened, whilst your pump wears. A running engine doesn't mean fine.
An old workaround for a different problem is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." None of what petrol thinned gets put back by it — and later, your tank still holds the petrol.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol sits in the filter and lines, ready to go right back through the pump at your next start. And, a can of petrol filled by the roadside is genuinely risky.
How petrol ends up: petrol in a diesel
It is seldom carelessness, and no one does it on purpose. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol car at all. The forecourt makes it easy, and the error runs one way.
It takes place when habit and the vehicle stop matching. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. The pumps in a different order on a well-known forecourt. A train to catch, and a hurried fill on the way to Oldfield Park. A new-to-you diesel Renault Clio, its first fuelling, and a driver accustomed to petrol: exactly when it occurs. With rain, a call arriving, or children to deal with, your hand just does what it always has.
Preventing petrol in a diesel next time you fill up in Norton Hill
- Read the pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on each forecourt. The label is what counts.
- In a motor you don't know, look inside the flap over your filler or at the cap before the first fill: plenty of cars state the fuel type there.
- Label the key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- Before the nozzle comes off the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Silly, yes, but it does the trick.
- Mistakes like this are straightforward to make while your mind is on something else, and so the phone goes away.
- Some diesels have a filler designed to block a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the pump.
- Stop the moment you notice. Less petrol inside your tank means a thinner mixture. It does not change what to do next, which is still not to fire it up.
Petrol already in a diesel around Norton Hill? Begin here
Short and simple, then, is the order of things. Don't turn the ignition on, and don't crank it. If you're still on the forecourt — Shell or anywhere else — ask the staff to help you push it away from the petrol pump. Then call 0333 366 0103 and tell us what got in, about how much, and whether it's run.
Corrosion and deposits form the issue with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and read its own Norton Hill page.
What makes one Norton Hill petrol in a diesel task cost more than the next
Four different tasks sit behind the four situations above — which is why there's no honest single price. Mostly, your cost moves with which situation you're in. Two things follow that: the petrol that went in as a share of what your tank takes, then the spot your car is in and whether a van can reach it safely.
What was put in, how much, and if it's run — three questions our engineers ask before costing, not after, for exactly that reason. Their replies are what turn a range into one firm number.
About Norton Hill and where it is
Norton Hill is a suburban area in Somerset, situated near the River Somer and the town of Midsomer Norton. Norton Hill sits at an elevation of around 128 metres, with views of the surrounding countryside and the nearby city of Bath. Norton Hill is characterized by its predominantly detached housing stock, reflecting its development as a residential area. Norton Hill is located approximately 8.7 miles from Bath and 102.5 miles from London.
Fuel drain cover across Somerset, Norton Hill included
Our teams answering petrol in diesel call-outs in Norton Hill, in the BA postcode area, equally work the places near it, Midsomer Norton, Providence Place and White Post included. We drain wherever the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
At the pump around Norton Hill, right now?
In that case, you could not be in a better position. Keep it off. Ring.