Petrol in a Diesel Car in Gatlas: How Worried Should You Be?
Not started? Then less anxious than you probably feel. Petrol sitting in a diesel tank does nothing to the motor until something draws it through the system — the ignition priming the pump, your starter, or driving itself. So the fair answer to the first query anyone in Gatlas asks, "have I wrecked it?", is normally no. To keep the car that way, call Petrol in Diesel and leave your motor switched off. What petrol actually does to a diesel, how to judge how far it's travelled, and how to stop it from happening again: that's the remainder of this page.
Petrol in a diesel: what does it do to the engine?
Diesel has two tasks on its way through a motor. It protects first, and after that does it burn. Extremely fine clearances are built into the injectors and your high-pressure pump, and only your diesel running through keeps those surfaces from grinding together.
Of these two tasks, petrol manages the first badly and the second not at all. Being less viscous than diesel, petrol strips away the protection a fuel system needs, so a pump on the blend wearing itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the knocking.
Together, those leave the shape of the problem plain. Contact doesn't do the damage — circulation does. Petrol in the tank is a fuel issue. Once the pump has been working on that petrol, a mechanical problem has begun: whatever is shed by a pump that is wearing down is carried onward to your injectors with your fuel.
How bad is petrol in a diesel? Four situations our technicians see in Gatlas
Fuelled up, never started. The best case there is. Just that tank has petrol in it, so the job is draining the tank and flushing the fuel system where your car stands. This situation can only truly take place on a forecourt: anywhere else, the vehicle got there by being driven.
A moment's running, or just your ignition on. Once primed, the fuel system has pulled petrol from that tank up to the filter and your lines. Normally little more than draining, flushing and seeing to the filter, and so still easy.
The pump has spent a few miles on weakened fuel — that's what driving the car meant. Tank, lines, filter, then clean fuel put through the whole system: that is the work, and the way the vehicle was driven counts as much as the distance. On the school run to the local primary school, the mileage is small. Any distance on the M4, under 3 miles from Gatlas, means the motor working hard throughout, and a run to Newport, under 5 miles away, is a very different task as well.
Driven on until it protested — knocking, smoke, a lumpy idle, a dead throttle. The engine is telling you the fuel is no longer acting like diesel. Pull up on the spot — on the verge on Usk Road, at the kerb, down a side road — and don't move it. What goes first is still the fuel drain and flush-through, and that takes care of it, with lasting damage very uncommon when a car is stopped soon.
What Gatlas drivers get told about petrol in a diesel — and the stories in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." Nothing is removed when you top up — that tank just holds more of the same blend. Percentage is not how a diesel fuel system tolerates petrol, however much that advice presumes.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. Finer components and higher pressure are how a modern diesel runs its fuel, and that makes the lubrication count more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches motorists. A petrol engine fed diesel generally will not run, and so the motorist stops and the damage stops with them. While the pump grinds, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. Fine and running are not the same thing.
Not so: a two-stroke additive makes it safe to drive home. It was an old fix, meant for another problem. The petrol is still inside the tank after that, and what it has thinned isn't put back.
Myth: "Drain the tank yourself and you're sorted." Once the motor has run, some of that petrol is no longer inside the tank: it's in the filter and the lines, and it goes straight back through your pump at your next start. Also, a can of petrol drained by the roadside is truly hazardous.
How it happens: petrol in a diesel
On purpose? Never. Through carelessness? Seldom, if ever. 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 error runs one way.
Routine and the car falling out of step is when it happens. A new motor, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Rushing for a train at Newport (South Wales) and filling up en route. Precisely the moment it takes place: after years of driving petrol, a driver fills a diesel Peugeot 308 for the first time. With rain, a call coming in, or a car full of children to deal with, the hand just does what it always has.
Gatlas drivers: how to avoid petrol in a diesel next time
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Read the petrol pump's label; the colour is only a clue.
- Inspect the filler flap. Many motors state the fuel type inside the flap or on the cap. Look at it on the first fill in a car you do not know.
- 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 gets its first tank. It seems silly. It works.
- Mistakes like this are straightforward to make while your mind is on something else, and so your phone goes away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler designed to refuse a petrol nozzle, and add-on devices are available for the remainder. Treat it as a safety net, and keep reading the pump.
- As soon as you realise, stop: less petrol inside the tank makes a thinner blend. What to do next does not change, though — still do not start the car.
Put petrol in a diesel in Gatlas already?
The order of things is short, then. Do not turn your ignition on, and don't start it. Yet on the forecourt, at JET or anywhere else? Ask the attendants to help you push it away from the pump. Then call 0333 366 0103 and tell us what was put in, roughly how much, and whether it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate problem — Gatlas has a page just for it.
Gatlas petrol in a diesel jobs: why one costs more than another
There's no fair single quote for this, because the four scenarios above are four separate jobs. Which of them you are in is chiefly what moves your cost. Where your car is counts too, and whether our van can safely reach it, after the ratio of petrol to what your tank takes.
That is why our technicians ask three questions before costing rather than after: what went in, how much, and if it's run. Given the replies, you get a straight figure rather than a range.
About Gatlas
Gatlas is a small locality situated on the riverside in Newport, Wales, with an elevation of 29 metres above sea level. Gatlas is located near several nearby places, including Llanhennock, Ponthir, and Common Cefn-llwyn, and is approximately 3.4 miles from the city of Newport. Gatlas has a population of around 548 people and is characterised by predominantly detached housing.
Across Newport and in Gatlas: fuel drain cover
Gatlas sits in the NP postcode area, and the teams that answer petrol in diesel calls there work the places around it as well — Llanhennock, Ponthir and Common Cefn-llwyn among them. You need not move your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
Gatlas: still at the pump?
Then, you couldn't be in a better spot. Ring, and keep it switched off.