Mickle Trafford: Petrol in a Diesel Car? How Worried to Be
Not started? Then less anxious than you likely are. Petrol resting in a diesel tank does nothing to the motor till something pulls it through the fuel system — your ignition priming your pump, the starter, or driving on its own. So the fair answer to the first question anyone around Mickle Trafford asks, "have I ruined it?", is generally no. Keep it that way: leave your engine off and phone Petrol in Diesel. The remainder of this page sets out 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.
Inside your engine: what petrol in a diesel really does
On its way through an engine, diesel has two jobs. Oiling comes before burning; it does both. Made to extremely fine gaps, the fuel injectors and the pump rely on your diesel moving through them to stop their surfaces wearing against one another.
Poorly at the first, not at all at the second: that is petrol. The knocking comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips out the lubrication the fuel system hinges on, and any pump working on that mix is wearing itself.
The shape of the trouble is plain when you put those together. It's movement that causes the harm, not contact. A tank with petrol in it is a fuel problem. After the pump has been working on that petrol, a mechanical problem has begun: anything shed by a pump that is wearing is carried downstream to the injectors with the fuel.
How bad is petrol in a diesel? Four situations our technicians see in Mickle Trafford
Filled but not once started — as good as it gets. The petrol is in that tank and just your tank, and the job is a drain and a flush where the vehicle sits. This is the one scenario that can only really take place on a forecourt, since anywhere else your car has been driven to get there.
A brief spell of running, or just your ignition on. With your system primed, your lines and filter now hold petrol that came from that tank. Drain, flush, see to the filter: still normally easy.
The pump now worked a couple of miles on thinned fuel — that's what driving the vehicle meant. Tank, lines, filter, then clean fuel run through the whole circuit: that's the work, and the way your car was driven matters as much as the distance. Short trips, such as the school run to Mickle Trafford Village School, are one matter. A run as far as Chester, under 5 miles away, is a very different job. So is any mileage on the M53, under 3 miles from Mickle Trafford, where the engine has been labouring hard the whole time.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven until it complained. The engine is telling you your fuel is no longer behaving like diesel. Whether it is the verge on Wilbraham Close, a lay-by or a side street, stop where you are then leave it. What goes first is still the drain and flush-through, and that deals with it, with permanent damage very rare if a car is stopped soon.
What Mickle Trafford people get told about petrol in a diesel — and the stories in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing is removed by topping up — you're left with a bigger tank, still the same mixture. Percentage isn't how a diesel fuel system copes with petrol, however much that guidance presumes.
Myth: a newer diesel copes with a bit of petrol. If anything, the opposite. At higher pressure, through more precise parts: that is how a newer diesel moves its fuel, and so the protection counts more, not less.
"It starts, it drives, so there is no harm" — the myth that catches most drivers than any other. The driver of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the damage stops there. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile your pump grinds. Running doesn't mean fine.
Myth: "Add some two-stroke oil and drive it home." It is an outdated workaround for a distinct problem. None of what petrol diluted gets put back by it — and later, that tank still contains the petrol.
Myth: "Drain that tank yourself and you're sorted." Once the motor has run, some of the petrol is no longer inside your tank: it's in the fuel filter and the lines, and it goes right back through your pump at the next start. On top of that, petrol drained into a can by the road is truly hazardous.
Why petrol in a diesel happens so easily
A careless moment is seldom the cause, and no one means to do it. A diesel nozzle mostly won't fit a petrol vehicle, yet the slimmer petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake straightforward, and only in that direction.
The moment routine stops matching the vehicle is the moment it happens. Any car that is new to you — a hire car, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. Your normal forecourt, its pumps now in a different order. A hurried fill on the way to Bache with a train to catch. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. With rain, a call arriving, or children to deal with, the hand just does what it has always done.
Preventing petrol in a diesel next time you fill up in Mickle Trafford
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most usually do. Read the pump's label; the colour is only a hint.
- In a car you do not know, look inside the flap over the filler or at the cap before your first fill: plenty of motors state the fuel there.
- A coloured fob or a sticker on your diesel's key does more than any amount of intending to remember, for a house with one of each.
- "Diesel", out loud, before you lift the nozzle — each time a new or hired car needs its first tank. It sounds daft. It works.
- Tuck your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Some diesels come with a filler designed to block a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the pump.
- Spotting it mid-fill? Stop at once. A weaker mixture results from less petrol in the tank, yet the next stage remains the same: do not fire it up.
Mickle Trafford: already put petrol in a diesel?
In that case, there is only a short order of things. Starting it is out, and so is turning on your ignition. The staff on the forecourt — whether at BP itself or wherever you filled up — will usually help push it clear of the pump if you ask. Next, 0333 366 0103. We will ask what went in, about how much, and if it has been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different issue — Mickle Trafford has a page all for it.
Why one petrol in a diesel job around Mickle Trafford costs more than another
The four scenarios above are four separate jobs, so no single quote for this would be honest. What shifts the cost is chiefly which of them you're in. Where the car is counts too, and whether a van can safely get to it, after the ratio of petrol to what that tank takes.
What got in, how much, and whether it has run — three queries our technicians ask before quoting, not after, for precisely that reason. The answers turn a range into a straight figure.
About Mickle Trafford and its setting
Mickle Trafford is a village in Cheshire, situated near the city of Chester and surrounded by other small settlements like Plemstall and Bridge Trafford. Mickle Trafford lies in a low-lying area, with an elevation of around 14 metres, and is characterized by its predominantly detached housing stock. Mickle Trafford is located approximately 3.4 miles from Chester, making it a commuter-friendly location. Mickle Trafford has a population of around 1563 residents, according to recent estimates.
Across Cheshire and around Mickle Trafford: fuel drain cover
Mickle Trafford sits in the CH postcode area, and our vans that answer petrol in diesel jobs there work the locations around it as well — Plemstall, Hoole Bank and Bridge Trafford among them. We drain where your car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the pump in Mickle Trafford?
The best place there is, then — that's where you are. Turned off it stays; then phone.