Petrol in a Diesel Car in Hillhead: How Worried Should You Be?
Not started? Then less worried than you likely are. Till your ignition primes your pump, the starter cranks, or the car is driven, petrol in a diesel tank simply sits there and does nothing. Which makes the honest reply to the first Hillhead question — "have I wrecked it?" — usually no. Leave your engine off and call Petrol in Diesel — that keeps it that way. The rest 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 does not happen to you again.
Your engine and petrol in a diesel: what goes on
On its way through an engine, diesel does two tasks. Lubricating comes before burning; it does both. Extremely fine tolerances go into your injectors and the high-pressure pump, and just the diesel flowing through stops their surfaces grinding together.
Petrol handles the first task badly and the second not at all. It is thinner than diesel and removes the protection the fuel system hinges on, so a pump running on a petrol mix is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the knocking comes from.
Seen together, they show the shape the problem takes. Contact doesn't do the damage — movement does. Petrol in a tank is a fuel fault. Once the pump has been running on that petrol, a mechanical problem has begun: anything shed by a pump that is wearing travels onward to the injectors with the fuel.
Petrol in a diesel around Hillhead: how bad is it? Four situations
The best case there can be: filled up, never started. Just your tank has petrol in it, and so the task is clearing your tank and rinsing the fuel system where the vehicle stands. This scenario can only really happen at a forecourt: anywhere else, the vehicle got there by being driven.
Ignition on, or started for a moment. Once primed, your system has pulled petrol from your tank as far as the fuel filter and the lines. Drain, flush, deal with the fuel filter: still usually straightforward.
Those few miles driven were the pump working on fuel diluted by petrol throughout. How hard the car was driven matters as much as how far, and this work covers the tank, the fuel lines, your filter and fresh fuel through the entire circuit. On the school run to Stratton Primary School, the distance is short. Any distance on the M5, under 50 miles from Hillhead, means your engine has worked hard throughout, and a run to Plymouth, under 50 miles away, makes a very different job as well.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. What you are hearing is the engine reporting fuel that no longer behaves like diesel. Whether it is the verge on Binhamy Road, a lay-by or a side street, stop there then leave it. A car stopped quickly very rarely has lasting damage, since the drain and the flush, which still come first, sort it out.
Petrol in a diesel myths Hillhead people hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. Topping up takes out nothing; it gives you a fuller tank of the same mix. Percentage isn't how a diesel fuel system tolerates petrol, whatever that guidance presumes.
If anything, the reverse is true. Myth: "A modern diesel can cope with a bit of petrol." Finer components and higher pressure are how a newer diesel runs its fuel, and that makes the lubrication matter more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there's no damage done." The motorist of a petrol motor fed diesel normally stops, because it will not run, and the harm stops there. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile your pump grinds. Fine and running aren't the same thing.
An old workaround for a separate fault is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has weakened remains thinned, and the petrol remains inside that tank regardless.
The next start draws petrol back round the pump from the lines and the fuel filter, where some of it sits after the motor has been run. That's why draining the tank yourself doesn't sort it — a myth. It's also genuinely hazardous to drain petrol into a can at the roadside.
Why petrol in a diesel occurs so easily
It is seldom carelessness, and nobody does it on purpose. One way only, since of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one mostly will not fit a petrol motor. That is how the forecourt makes it simple.
Habit and the car getting out of step is how it occurs. Any motor that's new to you — a hire car, on loan as a courtesy car, or brand new. A household with one petrol and one diesel on the driveway. The pumps in a different order on a well-known forecourt. A train to catch, and a hurried fill on the way to the nearest station. The first fill-up in a diesel Peugeot 308 after years of driving petrol is precisely the moment it happens. Throw in a back seat full of children, a phone call or rain, and habit wins.
How to avoid petrol in a diesel on your next fill-up around Hillhead
- A green handle for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Trust the label on the pump, not the colour.
- In a motor you don't know, look inside the flap over the filler or at the cap before the first fill: plenty of vehicles state the fuel type there.
- One of each in the house? Mark your key to the diesel — a coloured fob, a sticker — because intending to remember isn't enough.
- Before the nozzle leaves the petrol pump the first time you fuel a hired or new car, say "diesel" aloud. Daft, yes, but it works.
- Put the phone away. This is an easy mistake to make while you're thinking about something else.
- Add-on devices are available for vehicles without one, and some diesels are built with a filler that won't take a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label.
- Stop as soon as you realise. Less petrol inside that tank means a weaker mix. It does not change what to do next, which is still not to fire it up.
Already put petrol in a diesel in Hillhead?
The order of things is short, then. Starting it is out, and so is switching on the ignition. If you are still at the forecourt — Morrisons or anywhere else — ask the staff to help you roll the car clear of the pump. Ring 0333 366 0103 next, with three facts — the fuel, the rough quantity, and if it has run.
Say so if it was AdBlue rather than petrol: it's a different problem, with its own page for Hillhead, since AdBlue brings corrosion and deposits instead of lost protection.
What makes one Hillhead petrol in a diesel task cost more than the next
There's no honest single price for this, since the four scenarios above are four different tasks. Mostly, the cost moves with which one you're in. Beyond that it is the ratio — how much petrol got in against how much that tank takes — and after that where the vehicle is and whether a technician can reach it safely.
That is why our engineers ask three questions before quoting rather than after: what was put in, how much, and whether it has run. Their answers are what change a range into one firm number.
About Hillhead and its setting
Hillhead is a coastal suburban area in Cornwall, situated near the towns of Stratton and Poughill, with Flexbury also nearby. Hillhead sits at an elevation of 47 metres, overlooking the coastline of the South West region. Hillhead has a population of around 2762 people, predominantly living in detached housing. Hillhead is located approximately 35.7 miles from Plymouth and 196.1 miles from London.
Across Cornwall and around Hillhead: fuel drain cover
The vans answering petrol in diesel calls around Hillhead, in the EX postcode area, equally work the spots near it, Stratton, Poughill and Flexbury among them. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians drain, and your vehicle doesn't need to come to us.
At the petrol pump around Hillhead, still?
In that case, you couldn't be in a better spot. Keep it off. Phone.