How Worried Should You Be? Petrol in a Diesel Car in Lack
Unstarted? Then less anxious than you likely are. Everyone in Lack begins with "have I wrecked it?", and the fair answer is normally no: petrol resting inside the tank of a diesel stays harmless until priming, cranking or driving pulls it into your fuel system. Petrol in Diesel is who to ring, with the engine left off, so it remains that way. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and ways to make sure you don't repeat it.
What petrol in a diesel does to your engine
Diesel has two tasks on its way through an engine. It protects to begin with, and after that does it burn. Made to very fine clearances, the injectors and the pump rely on the diesel flowing through them to keep their surfaces from wearing against one another.
Poorly at the first, not at all at the second: that's petrol. The clattering comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips out the lubrication the fuel system depends on, and any pump working on such a mixture is wearing itself.
Seen together, they show what shape the problem takes. It's circulation that causes the harm, not contact. Where the petrol is only inside the tank, it is a fault of fuel, nothing more. A pump that has been labouring on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with the fuel to the fuel injectors downstream.
How serious is petrol in a diesel? Four scenarios our technicians see around Lack
The best case there is: filled up, never started. Being at a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol held inside the tank alone, it is drained and rinsed right where it stands, and nothing more is needed.
Started for a second, or only your ignition on. With the fuel system primed, the fuel lines and filter already contain petrol that came from your tank. That is normally still an easy task — a drain, a flush, and your filter seen to.
Those few miles on the road meant your pump working on fuel diluted by petrol the whole way. Mileage is only half of it; how hard it was driven matters just as much. Either way the work runs to your tank, the lines, the fuel filter and fresh fuel through the entire system. On the school run to the local primary school, the mileage is small. A run as far as Derry, under 50 miles away, is a very different job. So is any distance on the M77, over 50 miles from Lack, where the motor has been working hard throughout.
Driven on till it complained — clattering, smoke, a lumpy idle, a dead throttle. The engine is telling you your fuel is no longer acting like diesel. Stop wherever you are — the verge on Rock Street, a lay-by, a side street — then leave it where it is. The fuel drain and flush-through still come first, and they take care of it: when a vehicle is stopped early, permanent damage is very uncommon.
What Lack drivers get told about petrol in a diesel — and the myths in it
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Topping up removes nothing; it gives you a bigger tank of the same mixture. The idea behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
If anything, the opposite is true. Myth: "A current diesel can cope with a bit of petrol." More precise parts and higher pressure are the way a modern diesel runs its fuel, and that makes the protection count more, not less.
The myth that catches motorists out: if it starts and drives, it must be unharmed. Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the harm. Feed petrol to a diesel and it normally fires up, idles and drives away as if nothing happened — all while its pump is wearing. Being able to run is not the same as being fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate fault. It does not put back what petrol has thinned, and the petrol is still in the tank later on.
Myth: "Drain that tank yourself and you are sorted." Once the engine has been run, some of that petrol is no longer in that tank: it's in the filter and your lines, and it goes right back through the pump at the next start. And, a can of petrol filled at the roadside is genuinely hazardous.
Petrol in a diesel: how does it happen?
No one does it on purpose, and it is seldom carelessness. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slides into a diesel filler with almost no resistance, whilst a diesel nozzle mostly won't go into a petrol car at all. So the mistake runs one way.
Habit and the vehicle falling out of step is how it occurs. A new car, a hire car or a courtesy car. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. Racing for a train at the nearest station and fuelling up en route. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it happens. Your hand does what it has always done once you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel on your next fill-up in Lack
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Read the pump's label; the colour is just a hint.
- In a motor you don't know, look inside the flap over the filler or at the cap before your first fill: many vehicles state the fuel type there.
- A coloured fob or a sticker on your diesel's key does more than any amount of intending to remember, for a household with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It seems daft and it does the trick.
- Mistakes like this are easy to make whilst your mind is on something else, so your phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to reject a petrol nozzle, and aftermarket devices are available for the remainder. Treat it as a backstop, then keep checking the petrol pump.
- Stop as soon as you notice. Less petrol in your tank means a thinner mix. It does not change what to do next, which is still not to fire it up.
Petrol already in a diesel around Lack? Begin here
The order of things is brief, then. Don't turn your ignition on, and do not fire it up. The staff 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. What was put in, about how much, and if it's run: tell us that when you phone 0333 366 0103.
Corrosion and deposits form the issue with AdBlue, whereas petrol brings lost protection. So if it was AdBlue, say so — and read its own Lack page.
Why one petrol in a diesel task in Lack costs more than another
A fair single price does not exist here: four scenarios, four separate tasks. What shifts the cost is chiefly which of them you're in. Two things follow that: the petrol that got in as a share of what that tank holds, then the place your car is in and whether our van can get to it safely.
Ahead of any quote, not after, come three queries: your fuel that got in, the quantity, and whether it's run. That is why. Given those replies, there is a straight figure instead of a range.
About Lack and its setting
Lack is a small locality in County Fermanagh, situated inland at an elevation of 108 metres. Lack lies near the villages of Ederney and Dromore, and is approximately 32 miles from the city of Derry. Lack is characterised by its predominantly detached housing stock, reflecting its rural setting. Lack is home to around 520 residents, who live in a peaceful environment surrounded by the countryside of Northern Ireland.
Lack and County Fermanagh: where our fuel drain cover runs
Our vans answering petrol in diesel calls in Lack, in the BT postcode area, also work the spots around it, Ederney, Dooish and Dromore included. A forecourt, a supermarket car park, a lay-by or your own drive are all locations our engineers drain, and your car doesn't need to move to us.
Lack: still at the pump?
The best place there is, then — that's where you are. Keep the vehicle switched off, and ring.