Should You Worry? Petrol in a Diesel Car in Wallacestone
Unstarted? Then less worried than you probably feel. Till the ignition primes the pump, your starter turns, or the car is driven, petrol in a diesel tank just sits there and does nothing. Which means the truthful reply to that first Wallacestone query — "have I ruined it?" — normally no. To leave it like that, phone Petrol in Diesel then leave your engine switched off. The rest of this page explains what petrol really does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
What petrol in a diesel does to the motor
On its way through a motor, diesel does two jobs. Before it burns, it protects — and then it combusts. Built to very fine clearances, your injectors and your pump rely on your diesel flowing through them to keep their surfaces from wearing against one another.
Petrol does the first task poorly and the second not at all. It is runnier than diesel and takes away the protection the system depends on, and 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 reverse of what a diesel needs from its fuel. That's where the clattering comes from.
The shape of the trouble is plain when you put those together. The harm is done by circulation, not by contact. A tank with petrol in it is a fuel fault. After your pump has been working on that petrol, a mechanical issue has started: whatever is shed by a pump that's wearing travels downstream to the injectors with your fuel.
How bad is petrol in a diesel? Four scenarios we see around Wallacestone
The best case there is: filled up, never started. Just that tank has petrol in it, and so the job is draining that tank and flushing the fuel system where your car sits. This situation can only really occur at a forecourt: anywhere else, the car got there by being driven.
Started for a moment, or just your ignition on. The fuel system has been bled, and so petrol has left your tank and got to your filter and the fuel lines. Drain, flush, see to the filter: still usually easy.
Those few miles driven meant your pump working on fuel diluted by petrol throughout. Mileage is only half of that; how hard it was driven counts equally. Either way the work runs to that tank, the lines, the filter and clean fuel through the entire circuit. A school run to the local primary school is one thing. Driving as far as Stirling, under 15 miles away, makes a very different task — as does any distance on the M9, under 3 miles from Wallacestone, with the motor running hard the whole time.
Driven on till it complained — clattering, smoke, an uneven idle, a dead throttle. What you are hearing is your engine reporting fuel that no longer runs like diesel. Stop wherever you are — the verge on Comyn Drive, a lay-by, a side street — and leave the car where it is. A vehicle pulled over soon very rarely has long-term damage, since the fuel drain and the flush, which still go first, sort it out.
Wallacestone people and that petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Topping up removes nothing; it gives you a bigger tank of the same mix. That advice assumes a diesel fuel system handles petrol by percentage. It does not.
Not so: a modern diesel copes with a bit of petrol. Rather, the opposite. Lubrication matters more on modern diesels, not less, since their fuel runs through finer components at higher pressure.
One myth that catches drivers off guard: if it starts and drives, it must be unharmed. A petrol engine fed diesel normally won't run, so the motorist stops and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump wears. Being able to run isn't the same as being fine.
Myth: "Add some two-stroke oil and drive the car home." It's an old workaround for a different problem. The petrol is still in your tank after that, and whatever it has diluted isn't put back.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol lies in the filter and lines, waiting to go right back through your pump at your next start. It's also truly dangerous to drain petrol into a can at the kerbside.
How does petrol in a diesel occur?
Nobody does it on purpose, and it is rarely carelessness. A diesel nozzle generally won't go into a petrol vehicle, but the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and just in one direction.
It occurs when routine and the car stop matching. Courtesy car, hire car, or a motor that is brand new. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Filling up in a hurry en route to Polmont, with a train to catch. Precisely the moment it takes place: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. With rain, a call coming in, or a car full of children to deal with, the hand simply does what it always has.
Preventing petrol in a diesel next time you fill up around Wallacestone
- A green handle for unleaded and black for diesel is usual in the UK — yet not on every forecourt. Go by the label on the petrol pump, not the colour.
- In a vehicle you do not know, look inside the flap over the filler or at the cap before the first fill: plenty of motors print the fuel there.
- Mark the key. In a household 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 fuel a hired or new vehicle, say "diesel" out loud. Daft, yes, yet it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away and keep your mind on the petrol pump.
- Some diesels have a filler designed to refuse a petrol nozzle, and devices you can add are available for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump.
- As soon as you realise, stop: less petrol in that tank means a thinner blend. What to do next does not change, though — still don't start the vehicle.
Already put petrol in a diesel around Wallacestone?
Then, there's just a short order of things. Never crank it, and don't turn the ignition on. Still at the forecourt, at Esso or anywhere else? Ask the staff to help you push the vehicle away from the petrol pump. Next, 0333 366 0103. We'll ask what got in, roughly how much, and if it has been run.
If it was AdBlue instead of petrol, say so. That's a separate problem — corrosion and deposits and not lost lubrication — and it has its own page for Wallacestone.
Why one petrol in a diesel task in Wallacestone costs more than another
Four different tasks sit behind the four scenarios above — which is why there's no fair single quote. What moves the cost is mostly which of them you are in. Two things follow that: the petrol that was put in as a share of what that tank holds, then the spot the vehicle is in and whether a van can get to it safely.
What was put in, how much, and if it has run — three queries our engineers ask before quoting, not after, for exactly that reason. The answers turn a range into a straight figure.
About Wallacestone itself
Wallacestone is a village situated on the riverside in Falkirk, with a mix of rural and suburban characteristics. Wallacestone sits at an elevation of 133 metres, near the Forth Valley, and is located close to several nearby settlements, including Middlerig and Reddingmuirhead. Wallacestone has a population of around 1033 people, predominantly living in detached housing. Wallacestone is approximately 12 miles from Stirling, a major city in the region.
Across Falkirk and in Wallacestone: fuel drain cover
The vans answering petrol in diesel calls around Wallacestone, in the FK postcode area, equally work the locations around it, Middlerig, Reddingmuirhead and Brightons included. A forecourt, a supermarket car park, a lay-by or your own driveway are all spots our technicians drain, and your car does not need to come to us.
At the petrol pump in Wallacestone, still?
The best position there is, then — that is where you are. Switched off it remains; then call.