Petrol in a Diesel Car in Darranlas: How Worried Should You Be?
Probably less than you already are — as long as nobody has started the car. Till your ignition primes your pump, the starter cranks, or your vehicle is driven, petrol in a diesel tank simply rests there and does nothing. Which means the truthful reply to the first Darranlas query — "have I wrecked it?" — usually no. Petrol in Diesel is who to phone, with the engine left off, so it stays that way. What petrol actually does to a diesel, how to gauge how far it's travelled, and how to stop it from happening a second time: that is the rest of this page.
What petrol in a diesel does to your engine
On its way through an engine, diesel has two jobs. Oiling comes before burning; it does both. Extremely fine tolerances are built into the fuel injectors and the high-pressure pump, and just the diesel running through stops their surfaces grinding together.
Petrol handles the first job badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so a pump on the blend to wear itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the clattering.
The shape of the trouble is clear once you put those together. It's circulation that causes the damage, not contact. All a tank with petrol in it amounts to is a fuel fault. After your pump has been working on that petrol, a mechanical problem has started: whatever is shed by a pump that's grinding is carried onward to your injectors with the fuel.
Petrol in a diesel in Darranlas: how bad is it? Four cases
Filled but never started — as good as it gets. Only that tank has petrol in it, and so the job is emptying that tank and cleaning the system where your car stands. This scenario can only truly happen on a forecourt: anywhere else, your car got there by being driven.
Ignition on, or started for a second. With your system primed, your lines and filter now contain petrol that came from your tank. Normally nothing more than emptying, flushing and sorting the fuel filter, and so still simple.
A couple of miles driven, and the pump has spent each of them labouring on weakened fuel. How hard the car was driven matters as much as how far, and this work covers your tank, the fuel lines, the fuel filter and fresh fuel through the entire system. On the school run to the local primary school, the miles is small. Any miles on the M4, under 15 miles from Darranlas, means the engine working hard throughout, and a run to Cardiff, under 25 miles away, is a very different task as well.
Driven until it complained. Knocking, a ragged idle, smoke, a throttle that has gone soft. The fuel is not acting like diesel any more, and the motor is telling you. Leave it wherever it stops: a lay-by, a quiet street, the verge on Stream Street. The fuel drain and flush still go first, and they deal with it: when a vehicle is stopped quickly, long-term damage is very rare.
Petrol in a diesel myths Darranlas drivers hear
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing comes out when you top up — your tank just holds more of the same mixture. The idea behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. A current diesel runs its fuel through smaller components at higher pressure, which makes the lubrication matter more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools people. Feed diesel to a petrol motor and it usually will not run, and so the driver stops — and the damage stops with them. Feed petrol to a diesel and it usually fires up, idles and pulls away like 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, taken from a fix from years ago, for a distinct fault. The petrol is still inside that tank afterwards, and whatever it has thinned isn't put back.
Myth: "Drain the tank yourself and you're sorted." After the motor has run, some of that petrol is no longer inside that tank: it is in the fuel filter and the lines, and it goes right back through your pump on the next start. It's also truly dangerous to drain petrol into a can by the kerbside.
How it happens: petrol in a diesel
Carelessness is rarely the cause, and no one means to do it. The petrol nozzle is the smaller of the two and slips 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 easy, and the slip runs one way.
When habit and your car stop matching, it takes place. 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. Rushing for a train at Mountain Ash and filling up en route. Years of petrol motors behind you, a diesel Renault Clio in front of you on the forecourt for its first tank — that is when. The hand does what it has always done once you add rain, a phone call or a back seat full of children.
Preventing petrol in a diesel next time you fill up around Darranlas
- Read the pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on each forecourt. The label is what matters.
- In a car you do not know, look inside the flap over your filler or at the cap before the first fill: plenty of motors print the fuel there.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, for a household with one of each.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car needs its first tank. It sounds daft. It works.
- Put your phone away. This is an easy mistake to make while you are thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to reject a petrol nozzle, and add-on devices exist for vehicles without one. They are a backstop, not a reason to stop checking the pump.
- As soon as you realise, stop: less petrol in the tank means a thinner mixture. What to do next doesn't change, though — still do not fire it up.
Already put petrol in a diesel in Darranlas?
Short and simple, then, is the order of things. Don't switch the ignition on, and don't start it. The staff at the forecourt — whether at Esso itself or wherever you filled up — will normally help push it away from the pump if you ask. Call 0333 366 0103 next, with three facts — the fuel, the approximate volume, and whether it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a separate fault — Darranlas has a page all for it.
What makes one Darranlas petrol in a diesel job cost more than the next
A fair single price does not exist here: four scenarios, four separate jobs. Which of them you are in is mostly what shifts your cost. Where the vehicle is matters too, and whether a van can safely reach it, after the proportion of petrol to what that tank takes.
Three questions come first, before quoting, rather than after — what went in, how much, has it run — and that is the reason. A range becomes a straight figure once those answers are in.
About Darranlas and its setting
Darranlas is a suburban area situated on the riverside in Rhondda Cynon Taf, with a mix of terraced housing and local amenities. Darranlas sits at an elevation of around 140 metres, near the communities of Mountain Ash and Caegarw. Darranlas is located close to Cardiff, the capital city of Wales, and is part of the wider urban area along the riverside. Darranlas has a population of approximately 5669 residents.
Fuel drain cover across Rhondda Cynon Taf, Darranlas included
Darranlas sits in the CF postcode area, and the teams that answer petrol in diesel jobs there work the locations around it as well — Mountain Ash, Newtown and Caegarw among them. A forecourt, a supermarket car park, a lay-by or your own drive are all locations our technicians drain, and the vehicle does not need to move to us.
In Darranlas and still at the pump?
Nothing beats it: that's where you are. Keep it off. Phone.