Should You Worry? Petrol in a Diesel Car in Llangyfelach
Not started? Then less anxious than you probably are. "Have I ruined it?" is the first question everyone in Llangyfelach asks, and the honest answer is generally no, because petrol resting in a diesel tank harms nothing till it's drawn through your fuel system — by ignition priming, by your starter, or by driving. Keep it that way: leave your motor off then call Petrol in Diesel. The rest of this page sets out 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 your engine
Diesel has two jobs on its way through an engine. It combusts, and before it ignites it lubricates. What keeps the surfaces inside the high-pressure pump and the fuel injectors from wearing against one another is the diesel flowing through them — they are designed to very fine gaps.
The second task petrol does not do at all, and the first it does badly. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection the fuel system hinges on, and any pump working on that blend is wearing itself.
Together, those leave the shape of the issue plain. The harm is done by circulation, not by contact. Where that petrol is only inside your tank, it is an issue of fuel, nothing more. Whatever a worn pump sheds goes on, borne by your fuel, into the injectors downstream, which is why a pump that has been working on the petrol is where a mechanical problem starts.
How bad is petrol in a diesel? Four situations we see in Llangyfelach
Fuelled but not once started — the best it gets. Being on a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With that petrol kept in that tank alone, it's drained and purged right where it stands, and nothing more is needed.
Started for a moment, or only your ignition on. Once primed, the fuel system has pulled petrol out of the tank as far as the fuel filter and the fuel lines. Normally little more than clearing, flushing and seeing to your filter, so still simple.
A few miles driven, and the pump has spent every one of them working on thinned fuel. How hard the vehicle was driven counts as much as how far, and the work takes in your tank, the lines, the fuel filter and fresh fuel through the entire system. Short trips, like the school run to the local primary school, are one thing. Getting as far as Swansea, under 5 miles away, makes a very different job — as does any miles on the M4, under a mile from Llangyfelach, with your engine labouring hard all the way.
Driven until it complained. Rattling, a ragged idle, smoke, a throttle that has gone soft. That's the motor telling you its fuel has stopped acting like diesel. Whether it is the verge on Swansea Road, a lay-by or a side road, stop there then leave it. The drain and flush-through still go first, and they sort it out: if a vehicle is stopped quickly, long-term damage is very uncommon.
What Llangyfelach motorists get told about petrol in a diesel — and the myths in it
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. A diesel fuel system does not accept petrol by percentage in the way that advice supposes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. Finer components and higher pressure are how a current diesel runs its fuel, and that makes the lubrication count more, not less.
"It starts, it drives, and so no harm done" — the myth that catches most drivers than any other. Feed diesel to a petrol motor and it usually will not run, so the driver stops — and the damage stops with them. A diesel fed petrol usually starts, ticks over and drives away as though nothing has happened, whilst your pump wears. Running isn't the same as fine.
Not so: a two-stroke additive lets you to drive home. It was an old workaround, supposed for another problem. It does not put back what petrol has thinned, and the petrol is still inside your tank later.
Myth: "Drain that tank yourself and you are sorted." After the motor has been run, some of the petrol is no longer inside the tank: it is in the fuel filter and your lines, and it goes straight back through your pump on the next start. Besides, petrol cleared into a can by the road is truly risky.
Why petrol in a diesel takes place so easily
Carelessness is rarely the cause, and nobody means to do it. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol vehicle at all. The forecourt makes it simple, and the slip runs one way.
It occurs when routine and the vehicle stop matching. A new motor, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. A forecourt you know, only with its pumps laid out differently. Racing for a train outside Llansamlet and fuelling up en route. A new-to-you diesel BMW 3 Series, its first fuelling, and a motorist used to petrol: precisely when it occurs. Your hand does what it has always done when you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel at your next fill-up in Llangyfelach
- The label is what counts, and so read the pump rather than the colour: in the UK unleaded handles are normally green and diesel black, yet not on every forecourt.
- In a vehicle you do not know, look inside the flap over the filler or at the cap before your first fill: many cars print the fuel type there.
- One of each in the house? Label the key to your diesel — a bright fob, a sticker — because intending to remember isn't enough.
- It sounds silly and it does the trick: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the petrol pump.
- 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.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to refuse a petrol nozzle, and aftermarket devices are available for the remainder. Treat it as a safety net, and keep reading the petrol pump.
- Stop the moment you realise. Less petrol inside that tank makes a thinner mixture. It does not change what to do next, which is still not to crank it.
Llangyfelach: already put petrol in a diesel?
Then the order of things is short. Don't turn your ignition on, and don't crank it. Ask the attendants to help you roll it away from the petrol pump if you're still at the forecourt, whether that's Texaco or somewhere else. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it's been run.
If it was AdBlue instead of petrol, say so. That is a separate fault — corrosion and deposits instead of lost lubrication — and it has its own page for Llangyfelach.
Why one petrol in a diesel task around Llangyfelach costs more than another
The four scenarios above are four different tasks, so no single quote for this would be honest. Which of them you're in is mostly what shifts your cost. Two things follow that: the petrol that went in as a share of what that tank takes, then the spot your car is in and whether a technician can reach it safely.
Three queries come first, before quoting, rather than after — what got in, how much, has it run — and this is the reason. The answers change a range into a straight figure.
About Llangyfelach itself
Llangyfelach is a suburban area located inland, approximately 3.5 miles from Swansea, and sits at an elevation of 109 metres. Llangyfelach is characterised by its predominantly detached housing stock, reflecting the area's residential nature. Llangyfelach is situated near other local communities, including Mynydd-bach, Clase, and Tirdeunaw, and is part of the wider Swansea urban area.
Fuel drain cover across Swansea, Llangyfelach included
Petrol in diesel calls around Llangyfelach — part of the SA postcode area — go to teams that likewise cover the locations about it, Mynydd-bach, Clase and Tirdeunaw included. The car does not need to move to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Llangyfelach: still at the petrol pump?
Then you're in the best spot there is. Switched off it remains; then phone.