How Worried Should You Be? Petrol in a Diesel Car in Gasstown
Far less than you likely are, provided it has not been started. Everyone around Gasstown starts with "have I wrecked it?", and the honest answer is normally no: petrol left inside the tank of a diesel stays harmless until priming, cranking or driving draws it into the system. Keep it that way: leave the motor off and phone Petrol in Diesel. Below, you will find what petrol really does inside a diesel, how far it might have gone, and how to stop it happening to you again.
Petrol in a diesel: what does it do to your engine?
On its way through a motor, diesel has two tasks. Lubricating comes before burning; it does both. The high-pressure pump and your injectors are designed to very fine clearances, and your diesel passing through them is what keeps those surfaces from wearing down against one another.
The second task petrol doesn't do at all, and the first it does badly. The clattering comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication the system rests on, and any pump working on that blend is wearing itself.
Put those together and the shape of the problem is clear. The harm is done by circulation, not by contact. Petrol in a tank is a fuel fault. Once your pump has been running on that petrol, a mechanical fault has started: anything shed by a pump that is wearing down travels downstream to your injectors with your fuel.
Gasstown, petrol in a diesel: four cases, from mild to serious
Filled up, and not started: no case is better. On a forecourt, and genuinely only there, that petrol is still limited to that tank — since everywhere else the vehicle was driven to get to it. The task is draining and purging on the spot.
Started for a second, or just the ignition on. Once primed, the system has pulled petrol from the tank up to the fuel filter and the lines. Usually little more than draining, flushing and sorting your filter, and so still straightforward.
Your pump now spent a couple of miles on weakened fuel — that's what driving the vehicle does. The work is the tank, the lines, your filter and fresh fuel through the entire system, and how hard the vehicle was driven matters as much as how far. Driving the kids to the local primary school is one kind of trip. Very different again: a trip to Carlisle, under 50 miles away, or some mileage on the A74(M), under 10 miles from Gasstown, where your engine never stopped labouring hard.
Driven till it complained. Knocking, an uneven idle, smoke, a throttle that has gone soft. That is the motor telling you its fuel has stopped acting like diesel. Pull up wherever you are — the verge on Mid Row, a lay-by, a side street — and leave the car where it is. The fuel drain and flush-through still go first, and they take care of it: if a vehicle is stopped early, permanent damage is very rare.
Stories Gasstown people hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed when you top up — your tank just holds more of the same blend. The assumption behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. At higher pressure, through finer parts: that is how a current diesel moves its fuel, and so the lubrication counts for more, not less.
The myth that catches people out: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel usually has no choice but to stop, because it will not run, and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump grinds. Fine and running aren't the same thing.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different issue. That petrol is still in the tank afterwards, and whatever it has diluted isn't put back.
Myth: "Drain your tank yourself and you're sorted." Once your engine has been run, some of that petrol is no longer in the tank: it is in the fuel filter and the lines, and it goes right back through the pump at the next start. It is also truly risky to drain petrol into a can by the roadside.
How does petrol in a diesel occur?
No one does it on purpose, and it's rarely carelessness. A diesel nozzle mostly will not go into a petrol vehicle, but the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake straightforward, and just in one direction.
Routine and the car getting out of step is how it happens. Hire cars, courtesy cars, and cars that are new to you. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. Fuelling up in a hurry on the way to Dumfries, with a train to catch. A new-to-you diesel Volkswagen Passat, its first fuelling, and a motorist used to petrol: precisely when it happens. The hand does what it has always done when you add rain, a phone call or a back seat full of children.
Preventing petrol in a diesel next time you fill up in Gasstown
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Read the pump's label; the colour is just a clue.
- Inspect the filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on your first fill in a vehicle you do not know.
- One of each in the home? Label your key to the diesel — a bright fob, a sticker — because intending to remember isn't enough.
- It seems daft and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- Mistakes like this are simple to make while your mind is on something else, so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop checking the pump.
- Spotting it mid-fill? Stop there and then. A weaker blend follows from less petrol in the tank, but the next stage stays the same: do not fire it up.
Petrol already in a diesel around Gasstown? Start here
The order of things is brief, then. Never crank it, and don't turn the ignition on. The attendants on the forecourt — whether at the nearest petrol station itself or wherever you filled up — will usually help roll it clear of the pump if you ask. Then call 0333 366 0103 and tell us what was put in, roughly how much, and if it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a separate problem — Gasstown has a page just for it.
One petrol in a diesel task around Gasstown costs more than another. Why?
Four separate jobs sit behind the four scenarios above — which is why there is no fair single quote. The scenario itself does most of the work of moving the cost. The share matters next, meaning how much of the tank is petrol, followed by the location of the vehicle and whether reaching it is safe for a technician.
Three queries come first, before quoting, rather than after — what was put in, how much, has it run — and this is the reason. Those answers are what turn a range into one firm number.
About Gasstown, briefly
Gasstown is a suburban area situated on the riverside in Dumfries and Galloway, with a relatively low elevation of 19 metres. Gasstown lies near several smaller communities, including Gateside of Trench and Noblehill. Gasstown has a mix of housing types, but semi-detached homes are particularly prevalent in the area. Gasstown is located near the city of Carlisle, which is 28 miles away, and is also within a reasonable distance of larger towns and cities in southern Scotland.
Gasstown and Dumfries and Galloway: where our fuel drain cover reaches
Gasstown sits in the DG postcode area, and our teams that answer petrol in diesel jobs there work the locations around it as well — Gateside of Trench, Noblehill and Georgetown among them. You need not move the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots where we work.
Gasstown: still at the pump?
No position is better: that's where you now are. Keep it off. Call.