Petrol in a Diesel Car in Crofty: How Worried Should You Be?
Unstarted? Then less anxious than you likely are. Petrol resting in a diesel tank does nothing to your engine till something pulls it through your fuel system — your ignition priming the pump, the starter, or the drive itself. So the fair answer to the first question anyone in Crofty asks, "have I wrecked it?", is generally no. Leave your motor off and ring Petrol in Diesel — that is how you keep it that way. Below, you will find what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you again.
What petrol in a diesel does to your engine
Two jobs fall to diesel on its route round a motor. It ignites, and before it ignites it lubricates. Your high-pressure pump and the injectors are designed to extremely fine gaps, and your diesel passing through them is what stops those surfaces from wearing against one another.
Petrol handles the first task poorly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, leaving a pump running on the mixture wearing itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the clattering.
Put these together and the shape of the trouble is plain. Not contact but movement is what does the harm. Where that petrol is only inside your tank, it is a fault of fuel, nothing more. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to the injectors further on.
Crofty, petrol in a diesel: four situations, from mild to significant
The best case there is: filled up, never started. The petrol is inside your tank and just your tank, and the task is a drain and a flush where the vehicle stands. This is the one scenario that can only truly happen on a forecourt, because anywhere else your car has been driven to get there.
Started for a moment, or only the ignition on. Once primed, your system has drawn petrol from your tank up to the fuel filter and your lines. Still normally straightforward: drain, flush, and your filter sorted.
Driven a couple of miles. Now your pump has spent these miles working on thinned fuel. The work is your tank, your lines, the filter and clean fuel through the entire system, and how hard the vehicle was driven counts as much as how far. Short trips, like the school run to the local primary school, are one matter. A run as far as Swansea, under 10 miles away, is a very different task. So is any miles on the M4, under 10 miles from Crofty, where the engine has been working hard throughout.
Driven on till it complained — knocking, smoke, a ragged idle, a soft throttle. That is the motor telling you its fuel no longer is behaving like diesel. Leave it where it stops: a lay-by, a side street, the verge on Forge Road. The drain and flush still go first, and they deal with it: when a car is pulled over early, lasting damage is very uncommon.
Crofty people and the 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 takes out nothing; it gives you a fuller tank of the same mix. The idea behind the advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the reverse is true. Myth: "A modern diesel can cope with a bit of petrol." Smaller parts and higher pressure are the way a current diesel runs its fuel, and that makes the protection count more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there's no harm done." Feed diesel to a petrol engine and it usually will not run, so the driver stops — and the damage 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 the pump wears. Running doesn't mean fine.
Myth: a two-stroke additive lets you to drive home. It was an old fix, meant for another problem. None of what petrol diluted is put back by it — and afterwards, that tank still contains the petrol.
If your engine has run, part of that petrol sits in the fuel filter and the lines, not your tank — and your next start sends it straight back through the pump. So the myth "drain your tank yourself and you are sorted" does not hold. Besides, petrol drained into a can by the road is truly risky.
How petrol ends up: petrol in a diesel
Carelessness is seldom the cause, and no one means to do it. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol motor at all. The forecourt makes it simple, and the slip runs one way.
Habit and your car falling out of step is when it takes place. Hire cars, courtesy cars, and cars that are new to you. A household with one petrol and one diesel on the drive. A familiar forecourt with the pumps in a different order. Racing for a train at Bynea and filling up en route. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
How to avoid petrol in a diesel at your next fill-up around Crofty
- A green handle for unleaded and black for diesel is normal in the UK — but not on every forecourt. Go by the label on the pump, not the colour.
- In a vehicle you don't know, look inside the flap over the filler or at the cap before the first fill: plenty of vehicles print the fuel there.
- Good intentions count for less than a sticker or a fob in a bright colour on the diesel's key when a home has one of each. So label it.
- 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 daft and it does the trick.
- While you're thinking about something else, this is an easy mistake to make — so put the phone away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to reject a petrol nozzle, and add-on devices exist for the rest. Count it as a safety net, then keep reading the pump.
- Spotting it mid-fill? Stop there and then. A weaker mix follows from less petrol in your tank, yet your next step remains the same: do not fire it up.
Petrol already in a diesel in Crofty? Start here
Then, there is just a short order of things. Don't crank it, and don't switch the ignition on. Still at the forecourt, at North Road Service Station or anywhere else? Ask the staff to help you roll it clear of the petrol pump. What went in, about how much, and if it's run: tell us that when you ring 0333 366 0103.
Corrosion and deposits form the problem with AdBlue, whereas petrol brings lost lubrication. So if it was AdBlue, say so — and see its own Crofty page.
Crofty petrol in a diesel jobs: why one costs more than another
There is no honest single price for this, since the four situations above are four separate jobs. Which of them you're in is chiefly what moves your cost. Where the car is matters too, and whether a technician can safely get to it, after the ratio of petrol to what that tank takes.
That's why we ask three questions before quoting rather than after: what got in, how much, and if it's run. With the answers, you get a straight figure rather than a range.
About Crofty and where it is
Crofty is a small coastal village in Swansea, situated near the shores of the Bristol Channel at an elevation of around 14 metres. Crofty lies approximately 8 miles west of Swansea city centre and is surrounded by nearby villages such as Pen-caer-fenny and Llanmorlais. Crofty has a population of around 959 people and is characterised by its predominantly detached housing stock. Crofty enjoys a scenic location with views out to sea and access to local amenities.
Crofty and Swansea: where our fuel drain cover runs
Petrol in diesel call-outs in Crofty — part of the SA postcode area — go to vans that likewise cover the spots about it, Pen-caer-fenny, Llanmorlais and Wernffrwd included. The vehicle does not need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the petrol pump around Crofty?
Then, you could not be in a better spot. Keep it switched off, and ring.