Kitlye: Petrol in a Diesel Car? How Worried to Be
Probably less than you already are — as long as no one has started it. Everyone in Kitlye starts with "have I wrecked it?", and the fair answer is generally no: petrol left inside that tank of any diesel remains harmless till priming, cranking or driving draws it into your fuel system. To leave the vehicle like that, call Petrol in Diesel and leave your engine switched off. Below, this page sets out what petrol really does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
What petrol in a diesel does to the motor
Diesel does two jobs on its way through a motor. It lubricates first, and only then does it burn. The high-pressure fuel pump and the injectors are made to extremely fine gaps, and the diesel passing through them is what stops those surfaces from wearing against each other.
Of these two jobs, petrol handles the first badly and the second not at all. A pump running on a petrol mix is wearing itself out, since petrol is thinner than diesel and strips out the protection your fuel system depends on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where any rattling starts.
Put those together and the shape of the issue is clear. Contact doesn't do the damage — movement does. All a tank with petrol in it amounts to is a fuel problem. The start of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with the fuel to your injectors beyond it.
Four scenarios we see in Kitlye: how serious is petrol in a diesel?
Filled up, and never started: no case is better. Only your tank has petrol in it, so the job is emptying the tank and flushing the fuel system where the vehicle stands. This situation can only truly occur at a forecourt: anywhere else, your car got there by being driven.
Ignition on, or started for a moment. Once primed, the fuel system has drawn petrol out of that tank up to the filter and your lines. Usually little more than clearing, purging and sorting the filter, and so still easy.
Those few miles driven meant your pump labouring on fuel weakened by petrol throughout. The work is that tank, the lines, your filter and clean fuel through the entire system, and how hard the vehicle was driven counts as much as how far. On the school run to Eastcombe Primary School, the mileage is small. Very different a second time: a trip to Gloucester, under 10 miles away, or some distance on the M5, under 10 miles from Kitlye, where the motor never stopped working hard.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven till it complained. What you are hearing is your engine signalling fuel that no longer runs like diesel. Stop where you are — on the verge on Farleys Close, at the kerb, down a side road — and don't move it again. What goes first is still the drain and flush, and that takes care of it, with permanent damage very rare when a car is pulled over soon.
Kitlye people and that petrol in a diesel stories they hear
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 fuller tank, still the same mix. The assumption behind that 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. At higher pressure, through more precise parts: that's how a current diesel moves its fuel, and so the protection matters for more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there's no harm done." Feed diesel to a petrol engine and it normally won't run, and so the motorist stops — and the harm stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump grinds. Being able to run is not proof of being fine.
Myth: "Add some two-stroke oil and drive the car home." It is an outdated workaround for a distinct problem. What petrol has thinned stays thinned, and that petrol stays inside the tank regardless.
The next start sends petrol back round your pump from the lines and the filter, where some of it sits after the engine has been run. That's why a DIY tank drain doesn't leave you sorted — a myth. On top of that, petrol emptied into a can by the road is genuinely dangerous.
How it happens: petrol in a diesel
A careless moment is rarely the cause, and no one means to do it. The forecourt makes it easy: the petrol nozzle is the slimmer of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle mostly will not go into a petrol vehicle at all. So the error runs one way.
The moment routine stops matching the car is the moment it happens. Courtesy car, hire car, or a motor that's brand new. Households running one of each, petrol and diesel. The pumps in a different order on a familiar forecourt. A train to catch, and a hurried fill on the way to Stroud. A new-to-you diesel Volkswagen Passat, its first fuelling, and a driver used to petrol: exactly when it takes place. With rain, a call arriving, or children to deal with, the hand simply does what it always has.
How to avoid petrol in a diesel at your next fill-up around Kitlye
- Green for unleaded and black for diesel is normal in the UK — but not on each forecourt. Trust the label on the petrol pump, not the colour.
- Plenty of motors state the fuel inside the filler flap or on the cap, so check there on the first fill in any car you do not know.
- One of each in the home? Label your key to your diesel — a coloured fob, a sticker — since intending to remember isn't enough.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car needs its first tank. It seems silly. It does the trick.
- Mistakes like this are straightforward to make whilst your mind is on something else, and so the phone goes 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 vehicles without one. They are a safety net, not a reason to stop checking the pump.
- Noticing it mid-fill? Stop at once. A weaker blend results from less petrol inside that tank, but the next stage remains the same: do not fire it up.
Put petrol in a diesel in Kitlye already?
In that case, there is only a short order of things. Don't start it, and do not turn your ignition on. Still on the forecourt, at Murco or anywhere else? Ask the staff to help you roll the vehicle away from the petrol pump. What went in, roughly how much, and if it's run: tell us that when you call 0333 366 0103.
If it was AdBlue and not petrol, say so. That is a different issue — corrosion and deposits rather than lost lubrication — and it has its own page for Kitlye.
Why one petrol in a diesel task around Kitlye costs more than another
Four different jobs lie behind the four scenarios above — which is why there's no fair single quote. Mostly, your cost shifts with which one you are in. After that it's the ratio — how much petrol was put in against how much that tank takes — and after that where the car is and whether a technician can get to it safely.
That's why our engineers ask three questions before pricing rather than after: what got in, how much, and if it's run. A range turns into a straight figure when the replies are in.
About Kitlye itself
Kitlye is a locality in Gloucestershire, situated inland at an elevation of 225 metres, approximately 9.5 miles from Gloucester. Kitlye lies near the villages of Eastcombe and France Lynch, and is characterized by its predominantly detached housing stock. Kitlye is a relatively small community, with a population of around 674 residents, and is located within the wider South West region of England. Kitlye is also within commuting distance of major cities, being around 88.4 miles from London.
Kitlye and Gloucestershire: where our fuel drain cover runs
Our teams answering petrol in diesel jobs around Kitlye, in the GL postcode area, equally work the locations near it, Eastcombe, Chalford Hill and France Lynch included. A forecourt, a supermarket car park, a lay-by or your own drive are all locations our technicians work, and the car doesn't need to come to us.
In Kitlye and still at the pump?
In that case, you could not be in a better position. Keep it off. Call.