Should You Worry? Petrol in a Diesel Car in Millhayes
Less than you probably are, provided it hasn't been started. Everyone around Millhayes begins with "have I wrecked it?", and the honest answer is usually no: petrol left inside the tank of any diesel remains harmless till priming, cranking or driving pulls it into the system. Keep it that way: leave your engine off then ring Petrol in Diesel. What petrol really does to a diesel, how to judge how far it has gone, and how to keep it from happening again: that is the remainder of this page.
What petrol in a diesel does to the motor
Two jobs fall to diesel on its route through a motor. It combusts, and before it combusts it lubricates. What keeps the surfaces inside your high-pressure pump and the fuel injectors from wearing against each other is the diesel passing through them — they're made to very fine tolerances.
The second job petrol doesn't do at all, and the first it does badly. The rattling comes from petrol being made not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the protection your system hinges on, and any pump running on that mix is wearing itself.
Put these together and the shape of the problem is clear. Not contact but movement is what causes the damage. Any tank with petrol in it is a fuel problem. Whatever a worn pump sheds goes on, borne by your fuel, into the injectors further along, which is why a pump that has worked on the petrol is where a mechanical problem begins.
Four situations our technicians see around Millhayes: how bad is petrol in a diesel?
Filled up, never started. The best case there can be. On a forecourt, and genuinely only there, the petrol is still limited to your tank — because anywhere else the vehicle was driven to reach it. The job is emptying and flushing on the spot.
Started for a moment, or just the ignition on. The system has been primed, and so petrol has left the tank and reached the fuel filter and the lines. Still generally simple: drain, flush, and your filter seen to.
The pump has worked a few miles on diluted fuel — that's what driving it does. Mileage is only half of that; how hard it was driven matters just as much. Either way this work includes the tank, the fuel lines, the filter and fresh fuel through the whole circuit. Short trips, like the school run to Hemyock Primary School, are one matter. A run as far as Exeter, under 25 miles away, is a very different task. So is any distance on the M5, under 3 miles from Millhayes, where your engine has been running hard throughout.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The fuel isn't acting like diesel any more, and the engine is saying so. Whether it is the verge on Station Road, a lay-by or a side road, stop there then leave it. What comes first is still the drain and flush-through, and that takes care of it, with permanent damage very rare when a vehicle is pulled over quickly.
Millhayes people and the petrol in a diesel myths they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mix. That guidance supposes a diesel fuel system handles petrol by percentage. It doesn't.
If anything, the reverse is true. Myth: "A modern diesel can cope with a bit of petrol." At higher pressure, through more precise components: that's how a modern diesel moves its fuel, and so the protection counts for more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there's no harm done." Any petrol motor fed diesel normally will not run, and so the driver stops and the harm stops with them. While your pump wears, a diesel fed petrol normally starts, ticks over and drives away as if nothing has happened. Running is not the same as fine.
An old workaround for a different fault is behind this one. Myth: "Add some two-stroke oil and drive it home." What petrol has diluted remains weakened, and the petrol stays in the tank anyway.
Myth: "Drain that tank yourself and you're sorted." Once your engine has run, some of the petrol is no longer inside that tank: it is in the fuel filter and the lines, and it goes straight back through the pump on your next start. Emptying petrol into a can by the roadside is also genuinely hazardous.
Why petrol in a diesel happens so easily
Nobody does it on purpose, and it is rarely carelessness. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol motor at all. The forecourt makes it easy, and the slip runs one way.
It happens when habit and your car stop matching. A new vehicle, a hire car or a courtesy car. Two cars on one drive, one petrol, one diesel. A forecourt you know, only with its pumps laid out differently. A rushed fill on the way to Tiverton Parkway with a train to catch. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Renault Megane for the first time. 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 Millhayes
- Read the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on every forecourt. The label is what matters.
- In a vehicle you do not know, look inside the flap over the filler or at the cap before your first fill: many vehicles print the fuel there.
- Good intentions count for less than a sticker or a fob in a bright colour on your diesel's key if a house has one of each. So label it.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car gets its first tank. It seems silly. It works.
- Put your phone away. This is an easy mistake to make whilst you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to block a petrol nozzle, and add-on devices are available for vehicles without one. They are a safety net, not a reason to stop reading the petrol pump.
- Less petrol means a weaker blend, so stop as soon as you notice — though remembering that your next stage is unchanged. It is still not to start the vehicle.
Already put petrol in a diesel in Millhayes?
Short and simple, then, is the order of things. Never crank it, and do not switch the ignition on. The attendants at the forecourt — whether at BP itself or wherever you filled up — will usually help roll it clear of the petrol pump if you ask. Next, 0333 366 0103. We will ask what was put in, about how much, and if it has been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate fault — Millhayes has a page all for it.
What makes one Millhayes petrol in a diesel job cost more than the next
Four separate jobs sit behind the four situations above — which is why there's no honest single price. Mostly, your cost shifts with which situation you're in. Where the car is matters too, and whether a technician can safely get to it, after the ratio of petrol to what that tank holds.
Three questions come first, before quoting, rather than after — what went in, how much, has it run — and this is the reason. A range turns into a straight figure when the answers are in.
About Millhayes itself
Millhayes is a small village in Devon, situated on the riverside at an elevation of 128 metres. Millhayes lies near the villages of Ashculme, Hemyock, and Culm Davy, and is approximately 19 miles from the city of Exeter. Millhayes has a population of around 522 people, predominantly living in detached houses. Millhayes is located in the South West region of England, about 140 miles from London.
Fuel drain cover across Devon, Millhayes included
The teams answering petrol in diesel call-outs around Millhayes, in the EX postcode area, also work the locations around it, Ashculme, Hemyock and Culm Davy included. You need not move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
Still at the pump around Millhayes?
No position is better: that is where you are. Turned off it remains; then phone.