Should You Worry? Petrol in a Diesel Car in Holmesfield
Less than you likely are, if it hasn't been started. Until the ignition primes your pump, the starter turns, or the car is driven, petrol in a diesel tank simply sits there and does nothing. Which makes the honest reply to the first Holmesfield question — "have I wrecked it?" — normally no. Keep it like that: leave your motor off and ring Petrol in Diesel. The remainder of this page explains what petrol really does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you a second time.
The motor and petrol in a diesel: what goes on
On its way through an engine, diesel has two jobs. It combusts, and before it burns it lubricates. Very fine tolerances are built into the injectors and the high-pressure pump, and only your diesel running through keeps their surfaces from grinding together.
Petrol handles the first job poorly and the second not at all. It is runnier than diesel and removes the protection your fuel system rests on, so a pump running on a petrol mixture is a pump wearing itself. And petrol is made to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That is where the knocking comes from.
Combined, those make the shape of the issue clear. Contact does not do the harm — circulation does. Petrol in the tank is a fuel fault. Once your pump has been running on that petrol, a mechanical issue has begun: anything shed by a pump that's wearing down is carried onward to the fuel injectors with the fuel.
Four scenarios our engineers see around Holmesfield: how bad is petrol in a diesel?
Fuelled but not once started — as good as it gets. Only that tank has petrol in it, so the task is clearing that tank and rinsing the fuel system where your car sits. This scenario can only truly take place at a forecourt: anywhere else, the car got there by being driven.
The ignition turned on, or a brief start. Petrol has left your tank and reached your filter and your lines, because the fuel system has been bled. Drain, flush, deal with your filter: still usually straightforward.
Those few miles on the road were your pump running on fuel diluted by petrol throughout. Miles is only half of that; how hard it was driven matters equally. Either way the work includes that tank, your lines, the fuel filter and clean fuel through the entire circuit. Driving the kids to Penny Acres Primary School is one sort of trip. Driving as far as Sheffield, under 10 miles away, makes a very different task — as does any distance on the M1, under 10 miles from Holmesfield, with the motor labouring hard all the way.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven until it complained. The motor is telling you the fuel is no longer behaving like diesel. Pull up where you are — on the verge on Woodside Avenue, at the kerb, down a side road — and don't move it. Permanent damage is very unusual if a car is pulled over quickly, and the fuel drain and flush that still come first take care of it.
Myths Holmesfield motorists hear about petrol in a diesel
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 are left with a fuller tank, still the same mix. Percentage is not how a diesel fuel system tolerates petrol, whatever that guidance presumes.
If anything, the opposite is true. Myth: "A current diesel can cope with a bit of petrol." Lubrication matters more on modern diesels, not less, because their fuel runs through smaller parts at higher pressure.
The myth that catches people out: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it generally will not run, so the driver stops — and the harm stops with them. A diesel fed petrol usually starts, idles and drives away as if nothing has happened, whilst your pump wears. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct problem. It does not put back what petrol has thinned, and that petrol is still inside your tank afterwards.
Myth: "Drain that tank yourself and you are sorted." After your engine has run, some of that petrol is no longer inside the tank: it's in your filter and the fuel lines, and it goes right back through your pump on the next start. Also, a can of petrol filled by the kerbside is genuinely hazardous.
How does petrol in a diesel happen?
On purpose? Never. Through carelessness? Rarely, if ever. The forecourt makes it easy: the petrol nozzle is the smaller 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 slip runs one way.
When habit and the car stop matching, it occurs. Courtesy car, hire car, or a vehicle that's brand new. Two motors on one drive, one petrol, one diesel. Your usual forecourt, its pumps now in a different order. Rushing for a train at Dronfield and fuelling up en route. The first fill-up in a diesel Renault Clio after years of driving petrol is exactly the moment it happens. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
How to prevent petrol in a diesel at your next fill-up in Holmesfield
- Not every forecourt in the UK follows green for unleaded and black for diesel, even if most generally do. Check the petrol pump's label; the colour is only a hint.
- The first fill in an unfamiliar vehicle is the time to check the filler flap — inside it, or on the cap, many motors state the fuel they take.
- One of each in the house? Mark the key to your diesel — a bright fob, a sticker — because intending to remember isn't enough.
- Before the nozzle leaves the pump the first time you fuel a hired or new car, say "diesel" aloud. Daft, perhaps, but it does the trick.
- Tuck your phone away. This is an easy mistake to make while you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to refuse a petrol nozzle, and aftermarket devices exist for the remainder. Count it as a backstop, then keep checking the petrol pump.
- Less petrol makes a thinner mix, and so stop the moment you notice — while remembering that the next stage is unchanged. It is still not to crank it.
Put petrol in a diesel around Holmesfield already?
Then the order of things is short. Never start the vehicle, and don't switch your ignition on. The staff at the forecourt — whether at JET itself or wherever you filled up — will usually help roll it away from the petrol pump if you ask. Call 0333 366 0103 next, with three answers — the fuel, the approximate amount, and whether it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a different fault — Holmesfield has a page just for it.
One petrol in a diesel task in Holmesfield costs more than another. Why?
The four scenarios above are four different jobs, so no single quote for this would be honest. Chiefly, your cost moves with which situation you are in. Where the vehicle is counts too, and whether our van can safely get to it, after the ratio of petrol to what your tank holds.
Ahead of any quote, not after, come three questions: the fuel that was put in, its amount, and whether it's run. That's why. Those replies are what change a range into one firm number.
About Holmesfield
Holmesfield is a small village in Derbyshire, situated inland at an elevation of 252 metres, approximately 6.3 miles from Sheffield. Holmesfield has a population of around 583 people, with semi-detached housing being the predominant type. Holmesfield is surrounded by nearby places such as Cartledge, Cowley, and Horsleygate, and is located within the East Midlands region. Holmesfield is also relatively distant from London, at a distance of 136.7 miles.
Fuel drain cover across Derbyshire, Holmesfield included
Holmesfield sits in the S postcode area, and our vans that answer petrol in diesel call-outs there work the spots near it as well — Cartledge, Cowley and Horsleygate among them. The car doesn't need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Holmesfield and still at the pump?
No position is better: that's where you are. Turned off it remains; then phone.