Should You Worry? Petrol in a Diesel Car in Nettlebed
Provided it has not been started, you can worry less than you likely are. Petrol resting in a diesel tank does nothing to your motor till something draws it through your fuel system — your ignition priming your pump, the starter, or the drive on its own. So the fair answer to the first question anyone in Nettlebed asks, "have I ruined it?", is usually no. To leave the car that way, phone Petrol in Diesel and leave the engine switched off. The remainder of this page explains what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you a second time.
Your engine and petrol in a diesel: what happens
Two tasks fall to diesel on its route round a motor. It lubricates first, and after that does it burn. Built to very fine tolerances, the injectors and the pump rely on your diesel moving through them to keep their surfaces from wearing against one another.
Of these two jobs, petrol handles the first badly and the second never. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump on the mixture to wear itself. It is equally made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the rattling.
The shape of the trouble is plain when you put those together. Contact does not do the harm — circulation does. A tank with petrol in it is a fuel fault. A pump that has been labouring on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to your injectors further on.
Four scenarios we see in Nettlebed: how serious is petrol in a diesel?
The best case there can be: filled up, not once started. Being at a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol kept in the tank alone, it is emptied and flushed right where it stands, and nothing more is needed.
Your ignition switched on, or a brief start. With the system primed, the lines and filter already contain petrol that came from your tank. Still generally straightforward: drain, flush, and the filter seen to.
Those few miles driven were the pump working on fuel diluted by petrol throughout. The work is the tank, your lines, your filter and clean fuel through the whole system, and how hard the car was driven matters as much as how far. A school run to Nettlebed Community School is one thing. Any distance on the M40, under 10 miles from Nettlebed, means the motor working hard throughout, and a run to Oxford, under 25 miles away, is a very different job too.
Driven until it complained. Knocking, a lumpy idle, smoke, a throttle that has gone soft. That's your motor telling you its fuel has stopped acting like diesel. Whether it's the verge on Wanbourne Lane, a lay-by or a side street, stop where you are and leave it. What comes first is still the drain and flush-through, and that takes care of it, with lasting damage very uncommon if a vehicle is pulled over soon.
Stories Nettlebed people hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed when you top up — your tank simply carries more of the same blend. A diesel fuel system doesn't accept petrol by percentage in the way that guidance assumes.
"Current diesels can handle a little petrol" — a myth, and closer to the opposite. Smaller parts and higher pressure are the way a current diesel runs its fuel, and that makes the lubrication matter more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches motorists. The driver of a petrol engine fed diesel normally stops, because it will not run, and the harm stops with them. Feed petrol to a diesel and it usually starts, idles and drives away like nothing has happened — all while its pump is wearing. Running is not 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 doesn't put back what petrol has weakened, and that petrol is still in that tank later on.
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's in the fuel filter and the lines, and it goes right back through the pump at your next start. And, a can of petrol drained at the kerbside is truly risky.
How it happens: petrol in a diesel
A careless moment is seldom the cause, and nobody means to do it. One way only, since of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one generally will not fit a petrol car. That's how the forecourt makes it simple.
The moment habit stops matching the car is the moment it occurs. Courtesy car, hire car, or a motor that is brand new. Households running one of each, petrol and diesel. Your normal forecourt, its pumps now in a different order. Rushing for a train at Henley-On-Thames and filling up en route. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Golf 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.
Preventing petrol in a diesel next time you fill up in Nettlebed
- The label is what matters, and so read the petrol pump instead of the colour: in the UK unleaded handles are usually green and diesel black, but not on each forecourt.
- Plenty of cars state the fuel type inside the filler flap or on the cap, so check it on your first fill in a vehicle you do not know.
- One of each in the home? Mark your key to your diesel — a coloured fob, a sticker — since meaning to remember isn't enough.
- Before the nozzle comes off the petrol pump the first time you fuel a hired or new vehicle, say "diesel" aloud. Silly, perhaps, but it does the trick.
- While you are thinking about something else, this is an easy mistake to make — so put the phone away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to reject a petrol nozzle, and add-on devices are available for vehicles without one. They are a backstop, not a reason to stop reading the pump.
- The moment you realise, stop: less petrol inside the tank means a thinner mixture. What to do next does not change, though — still don't start it.
Already put petrol in a diesel around Nettlebed?
Then the order of things is short. Leave it unstarted, with the ignition switched off as well. Ask the staff to help you roll it clear of the petrol pump if you are still on the forecourt, whether that's BP or somewhere else. What got in, about how much, and whether it's run: tell us those when you ring 0333 366 0103.
If it was AdBlue rather than petrol, say so. That is a separate fault — corrosion and deposits instead of lost lubrication — and it has its own page for Nettlebed.
What makes one Nettlebed petrol in a diesel task cost more than the next
Four separate tasks sit behind the four situations above — which is why there's no fair single quote. What shifts your cost is chiefly which of them you are in. Beyond that it is the proportion — how much petrol was put in against how much your tank takes — and after that where the car is and whether our van can reach it safely.
That is why we ask three questions before quoting instead of after: what was put in, how much, and if it has run. A range becomes a straight figure once the replies are in.
About Nettlebed and where it is
Nettlebed is a small village in south Oxfordshire, situated in a rural area with a mix of woodland and farmland. Nettlebed sits at an elevation of 196 metres, with nearby settlements including Crocker End and Huntercombe End. Nettlebed is characterized by its predominantly detached housing stock, reflecting its role as a residential community within commuting distance of Oxford. Nettlebed is also within reach of London, being approximately 37 miles to the southwest of the capital.
Across Oxfordshire and around Nettlebed: fuel drain cover
Our teams answering petrol in diesel calls around Nettlebed, in the RG postcode area, equally work the spots around it, Crocker End, Catslip and Huntercombe End among them. Our technicians 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.
Nettlebed: still at the petrol pump?
The best spot there is, then — that is where you are. Turned off it stays; then phone.