Should You Worry? Petrol in a Diesel Car in Greenham
Not started? Then less worried than you likely are. Everyone in Greenham begins with "have I ruined it?", and the fair answer is usually no: petrol left in the tank of a diesel stays harmless till priming, cranking or driving draws it into your fuel system. To keep the car that way, phone Petrol in Diesel and leave your motor alone. What petrol really does to a diesel, how to judge how far it's travelled, and how to stop it from happening a second time: that is the rest of this page.
Inside the engine: what petrol in a diesel does
On its way through an engine, diesel does two tasks. Before it burns, it protects — then it combusts. Your high-pressure pump and the fuel injectors are designed to very fine clearances, and the diesel passing through them is what keeps those surfaces from grinding against each other.
Poorly at the first, not at all at the second: that's petrol. A pump running on a petrol mixture is wearing itself out, since petrol is runnier than diesel and strips out the lubrication your fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where the clattering starts.
Put those together and the shape of the problem is clear. Not contact but movement is what does the damage. All a tank with petrol in it amounts to is a fuel issue. Whatever a worn pump sheds goes on, carried by your fuel, into the fuel injectors downstream, which is why a pump that has worked on that petrol is where a mechanical fault starts.
How serious is petrol in a diesel? Four situations our technicians see around Greenham
Fuelled but never started — the best it gets. At a forecourt, and truly only there, that petrol is still confined to that tank — since anywhere else the car was driven to reach it. The job is emptying and cleaning on the spot.
Ignition on, or started for a moment. Petrol has left your tank and reached your filter and the fuel lines, since the system has been bled. That is usually still a simple job — a drain, a flush, and your filter dealt with.
A couple of miles driven, and your pump has spent each of them running on diluted fuel. How hard your car was driven counts as much as how far, and the work covers your tank, the lines, the filter and clean fuel through the entire circuit. On the school run to The Willows Primary School, the mileage is small. Very different again: a trip to Winchester, under 25 miles away, or any distance on the M4, under 5 miles from Greenham, where the motor never stopped working hard.
Driven until it complained. Clattering, a ragged idle, smoke, a throttle that has gone soft. The fuel isn't behaving like diesel any more, and your engine is telling you. Whether it is the verge on Greenham Road, a lay-by or a side street, stop there then leave it. The drain and flush-through still come first, and they take care of it: if a vehicle is pulled over quickly, long-term damage is very uncommon.
Greenham drivers and that petrol in a diesel stories they hear
Myth: "Fill it the rest of the way with diesel and it will be fine." It will not. A bigger tank of the same mix is all you get, because topping up removes nothing. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance supposes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. Protection matters more on newer diesels, not less, because their fuel runs through smaller parts at higher pressure.
"It starts, it drives, and so there is no harm" — the myth that trips up more motorists than any other. A petrol engine fed diesel normally won't run, and so the driver stops and the damage stops with them. Whilst your pump grinds, a diesel fed petrol usually starts, idles and drives away as though nothing has happened. Running isn't 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 separate fault. The petrol is still inside that tank afterwards, and what it has weakened isn't put back.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol lies in your filter and lines, ready to go straight back through your pump on your next start. It is also truly risky to drain petrol into a can by the kerbside.
How petrol ends up: petrol in a diesel
It is rarely carelessness, and no one does it on purpose. A diesel nozzle generally will not fit a petrol vehicle, but the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and only in one direction.
The moment routine stops matching the vehicle is the moment it occurs. A new motor, a hire car or a courtesy car. Two cars on one driveway, one petrol, one diesel. The pumps in a different order on a familiar forecourt. A train to catch, and a hurried fill on the way to Newbury Racecourse. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. The hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
Greenham people: how to avoid petrol in a diesel next time
- A green handle for unleaded and black for diesel is usual in the UK — yet not on each forecourt. Trust the label on the petrol pump, not the colour.
- The first fill in an unfamiliar motor is the time to check the filler flap — on it, or on the cap, plenty of motors state the fuel to use.
- Good intentions do less than a sticker or a fob in a vivid colour on the diesel's key if a home has one of each. So label it.
- "Diesel", aloud, before you pick up the nozzle — every time a new or hired car gets its first tank. It seems daft. It works.
- Mistakes like this are straightforward to make while your mind is on something else, and so your phone goes away.
- 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 backstop, not a reason to stop checking the pump.
- Less petrol makes a thinner blend, so stop the moment you notice — while remembering that the next step is unchanged. It's still not to fire it up.
Already put petrol in a diesel around Greenham?
Then, there is only a short order of things. Do not fire it up, and do not switch your ignition on. If you are still at the forecourt — Tesco or anywhere else — ask the staff to help you roll the car away from the petrol pump. Call 0333 366 0103 next, with three answers — your fuel, the rough volume, and if it's run.
Corrosion and deposits are the problem with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and see its own Greenham page.
What makes one Greenham petrol in a diesel job cost more than the next
There's no fair single price for this, because the four situations above are four separate tasks. Mostly, the cost moves with which situation you're in. Where your car is counts too, and whether a van can safely get to it, after the ratio of petrol to what your tank takes.
Before any quote, not after, we ask three queries: the fuel that was put in, its amount, and if it has run. That's why. A range becomes a straight figure once those replies are in.
About Greenham, for a moment
Greenham is a rural village in Berkshire, situated inland at an elevation of around 128 metres. Greenham lies approximately 51.5 miles west of London and 22.3 miles north of Winchester, with nearby areas including Burys Bank, East Fields, and Newtown. Greenham has a population of around 1456 people, predominantly living in detached houses.
Across Berkshire and in Greenham: fuel drain cover
Greenham sits in the RG postcode area, and our teams that answer petrol in diesel jobs there work the spots near it as well — Burys Bank, East Fields and Newtown among them. A forecourt, a supermarket car park, a lay-by or your own drive are all locations we work, and your vehicle does not need to come to us.
In Greenham and still at the petrol pump?
Then you are in the best place there is. Switched off it remains; then phone.