How Worried Should You Be? Petrol in a Diesel Car in Week
If it has not been started, worry far less than you likely are. "Have I ruined it?" is the first thing anyone in Week asks, and the truthful answer is usually no, since petrol resting in a diesel tank harms nothing till it is dragged through the system — by ignition priming, by your starter, or by driving. To keep it like that, phone Petrol in Diesel then leave your motor alone. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to stop it from happening a second time: that's the remainder of this page.
Inside the engine: what petrol in a diesel really does
On its way through a motor, diesel does two jobs. It ignites, and before it burns it protects. What keeps the surfaces inside your high-pressure pump and the injectors from grinding against one another is the diesel flowing through them — they're made to very fine clearances.
Poorly at the first, not at all at the second: that is petrol. The clattering comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication your system depends on, and any pump working on that blend is wearing itself.
Taken together, they show what shape the issue takes. Not contact but circulation is what does the damage. All a tank with petrol in it amounts to is a fuel issue. Whatever a worn pump sheds travels on, borne by your fuel, into the fuel injectors downstream, which is why a pump that has been working on that petrol is where a mechanical problem begins.
Four scenarios our technicians see around Week: how serious is petrol in a diesel?
Fuelled but not once started — as good as it gets. At a forecourt, and really only there, the petrol is still limited to the tank — because anywhere else the vehicle was driven to get to it. The task is emptying and purging on the spot.
Started for a moment, or only the ignition on. With the fuel system primed, the lines and filter already hold petrol that came from your tank. Usually nothing more than draining, purging and sorting the filter, and so still easy.
Some miles driven, and your pump has spent each of them running on thinned fuel. Tank, lines, filter, then clean fuel run through the whole system: that is the work, and the way your car was driven matters as much as the miles. A school run to Dartington Church of England Academy is one matter. Driving as far as Plymouth, under 25 miles away, makes a very different task — as does any mileage on the M5, under 25 miles from Week, with your engine running hard the whole time.
Driven until it complained. Clattering, an uneven idle, smoke, a throttle that has gone soft. That's the engine telling you its fuel has stopped acting like diesel. Whether it is the verge on Sawfield Drive, a lay-by or a side street, stop where you are and leave it. The drain and flush still go first, and they take care of it: when a vehicle is stopped early, long-term damage is very unusual.
Myths Week people hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Topping up takes out nothing; it gives you a fuller tank of the same mixture. Percentage is not how a diesel fuel system tolerates petrol, however much that advice assumes.
If anything, the opposite holds. Myth: "A current diesel can cope with a bit of petrol." A current diesel runs its fuel through finer parts at higher pressure, which makes the lubrication count more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that catches motorists. Feed diesel to a petrol engine and it generally won't run, and so the driver stops — and the harm stops with them. Feed petrol to a diesel and it generally fires up, ticks over and drives away like nothing has happened — all while its pump is wearing. Fine and running are not the same thing.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate issue. None of what petrol diluted is put back by it — and later, the tank still contains the petrol.
The next start draws petrol back round the pump out of the fuel lines and the fuel filter, where some of it sits once your engine has run. That's why draining your tank yourself doesn't sort it — a myth. Draining petrol into a can by the roadside is also truly risky.
Petrol in a diesel: how does it happen?
On purpose? Never. Through carelessness? Seldom, if ever. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle generally won't go into a petrol motor at all. So the slip runs one way.
Habit and the vehicle getting out of step is how it occurs. Hire cars, courtesy cars, and motors that are new to you. One petrol and one diesel on the drive of the same household. Your normal forecourt, its pumps now in a different order. Rushing for a train at Totnes and filling up en route. A new-to-you diesel Renault Clio, its first fuelling, and a driver used to petrol: exactly when it takes place. Add rain, a phone call or a back seat full of children, and the hand does what it has always done.
How to prevent petrol in a diesel at your next fill-up around Week
- Check the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, yet not on each forecourt. The label is what counts.
- The first fill in a strange vehicle is the time to check the filler flap — inside it, or on the cap, plenty of motors state which fuel they take.
- Mark the key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- It sounds daft and it does the trick: on the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump.
- Thinking about something else is when this becomes an easy mistake to make, so put the phone away and keep your mind on the pump.
- Some diesels have a filler designed to block a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the petrol pump.
- Less petrol makes a thinner mix, and so stop the moment you realise — though remembering that your next step is unchanged. It is still not to fire it up.
Petrol already in a diesel in Week? Begin here
Then, there is just a short order of things. Do not start the vehicle, and do not turn the ignition on. If you are still at the forecourt — Texaco or anywhere else — ask the staff to help you push the car away from the petrol pump. Phone 0333 366 0103 next, with three answers — your fuel, the approximate amount, and whether it has run.
Corrosion and deposits form the issue with AdBlue, whereas petrol brings lost lubrication. So if it was AdBlue, say so — and see its own Week page.
What makes one Week petrol in a diesel task cost more than the next
An honest single price does not exist here: four situations, four separate jobs. Chiefly, your cost shifts with which situation you're in. Where the car is matters too, and whether our van can safely get to it, after the ratio of petrol to what that tank takes.
That is why we ask three questions before pricing rather than after: what got in, how much, and if it's run. With those replies, there is a straight figure rather than a range.
About Week, briefly
Week is a small village in Devon, situated on the riverside at a low elevation of around 30 metres. Week lies near Shinners Bridge and Huxhams Cross Estate, within commuting distance of Plymouth, which is approximately 19 miles away. Week has a population of around 571 people, predominantly living in detached houses.
Fuel drain cover around Week and across Devon
Petrol in diesel jobs around Week — part of the TQ postcode area — go to teams that also cover the places round it, Shinners Bridge, Huxhams Cross Estate and Cott included. A forecourt, a supermarket car park, a lay-by or your own drive are all locations we drain, and your vehicle does not need to come to us.
Week: still at the petrol pump?
In that case, you couldn't be in a better place. Ring, and keep it switched off.