Petrol in a Diesel Car in Ely: How Worried Should You Be?
Provided it has not been started, you can worry less than you likely are. Till the ignition primes your pump, your starter cranks, or the vehicle is driven, petrol in a diesel tank simply sits there and does nothing. Which makes the honest reply to the first Ely question — "have I wrecked it?" — usually no. Keep it like that: leave the motor off then phone Petrol in Diesel. Below, this page sets out what petrol really does inside a diesel, how far it may have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to your engine?
Two jobs fall to diesel on its route round a motor. Lubricating comes before burning; it does both. What keeps the surfaces inside your high-pressure pump and the fuel injectors from wearing against each other is your diesel flowing through them — they're built to extremely fine tolerances.
The second task petrol does not do at all, and the first it does poorly. Being less viscous than diesel, petrol strips away the protection a fuel system needs, leaving a pump running on the blend to wear itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is where you get the clattering.
Together, those leave the shape of the trouble plain. Not contact but movement is what does the harm. Where that petrol is only in that tank, it's a problem of fuel, nothing more. After the pump has been working on that petrol, a mechanical issue has begun: anything shed by a pump that is wearing down travels onward to the injectors with the fuel.
How bad is petrol in a diesel? Four scenarios we see in Ely
The best case there can be: filled up, not once started. Just that tank has petrol in it, so the job is draining the tank and cleaning the fuel system where the vehicle stands. This scenario can only truly take place on a forecourt: anywhere else, your car got there by being driven.
Ignition on, or started for a moment. With your system primed, your lines and filter already contain petrol that has come from the tank. Drain, flush, see to the fuel filter: still usually simple.
Driven a few miles. Now your pump has spent those miles labouring on weakened fuel. Tank, lines, filter, then fresh fuel put through the whole circuit: that is the work, and the way the vehicle was driven counts as much as the miles. The school run to the local primary school is one thing. Any mileage on the M4, under 3 miles from Ely, means your engine has worked hard throughout, and a run to Cardiff, under 5 miles away, is a very different task as well.
Driven on until it complained — rattling, smoke, a lumpy idle, a dead throttle. The fuel is not acting like diesel any more, and the motor is telling you. Stop on the spot — on the verge on Grand Avenue, at the kerb, down a side road — and don't move it. What goes first is still the drain and flush-through, and that sorts it out, with long-term damage very uncommon if a vehicle is stopped early.
Stories Ely people hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. Percentage isn't how a diesel fuel system tolerates petrol, however much that guidance supposes.
Myth: a newer diesel copes with a bit of petrol. Rather, the reverse. At higher pressure, through finer components: that's how a modern diesel moves its fuel, so the protection counts more, not less.
The myth that catches people off guard: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it normally won't run, so the motorist stops — and the damage stops with them. A diesel fed petrol generally starts, idles and drives away as if nothing has happened, while the pump wears. Fine and running are not the same thing.
Myth: "Add some two-stroke oil and drive it home." It's an old fix for a separate fault. None of what petrol weakened is put back by it — and afterwards, your tank still contains that petrol.
The next start draws petrol back round the pump from the lines and the fuel filter, where some of it sits after your engine has run. That is why a DIY tank drain does not leave you sorted — a myth. Also, a can of petrol filled at the roadside is genuinely dangerous.
Petrol in a diesel: how does it take place?
A careless moment is seldom the cause, and no one means to do it. The petrol nozzle is the slimmer of the two and slides into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol vehicle at all. The forecourt makes it simple, and the slip runs one way.
The moment habit stops matching the vehicle is the moment it takes place. A new motor, a hire car or a courtesy car. Two vehicles on one drive, one petrol, one diesel. A familiar forecourt with the pumps in a different order. A train to catch, and a rushed fill en route to Waun-Gron Park. Years of petrol vehicles behind you, a diesel BMW 3 Series in front of you at the forecourt for its first tank — that is when. Your hand does what it has always done when you add rain, a phone call or a back seat full of children.
Next time you fill up around Ely: avoiding petrol in a diesel
- The label is what matters, and so read the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- In a vehicle you do not know, look inside the flap over your filler or at the cap before your first fill: plenty of vehicles state the fuel type there.
- Mark your key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car gets its first tank. It seems silly. It does the trick.
- Whilst you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to block a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop reading the pump.
- Spotting it halfway? Stop at once. A weaker blend follows from less petrol inside the tank, yet the next step stays the same: don't fire it up.
Petrol already in a diesel around Ely? Begin here
The order of things is brief, then. Do not crank it, and do not switch your ignition on. Ask the attendants to help you roll it away from the pump if you are still at the forecourt, whether that is Esso or anywhere else. Next, 0333 366 0103. We'll ask what was put in, roughly how much, and if it has been run.
Corrosion and deposits form the issue with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and read its own Ely page.
What makes one Ely petrol in a diesel task cost more than the next
The four scenarios above are four separate tasks, so no single quote for this would be honest. What moves your cost is mostly which of them you're in. After that it's the proportion — how much petrol got in against how much your tank holds — and then where the vehicle is and whether our van can get to it safely.
Ahead of any quote, not after, we ask three queries: your fuel that went in, the amount, and if it has run. That is why. Those answers turn a range into a straight figure.
About Ely itself
Ely is a suburban area in Cardiff, situated on the banks of the River Ely, with a mix of semi-detached housing and local amenities. Ely sits approximately 3 miles west of Cardiff city centre, at an elevation of around 30 metres above sea level. Ely is close to nearby suburbs such as Caerau, Fairwater, and Cyntwell, and is part of the wider Cardiff urban area. Ely has a population of around 8974 people, according to recent estimates.
Fuel drain cover around Ely and across Cardiff
Ely sits in the CF postcode area, and the teams that answer petrol in diesel call-outs there work the places around it as well — Caerau, Fairwater and Cyntwell among them. Our engineers drain where the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Ely: still at the petrol pump?
The best position there is, then — that's where you are. Turned off it stays; then ring.