How Worried Should You Be? Petrol in a Diesel Car in Greenhill
Probably less than you already are — as long as nobody has started the car. "Have I ruined it?" is the first thing everyone around Greenhill asks, and the honest answer is normally no, since petrol left in a diesel tank harms nothing until it's drawn through your fuel system — by ignition priming, by your starter, or by being driven. Leave your motor off then ring Petrol in Diesel — that keeps it that way. What petrol actually does to a diesel, how to gauge how far it's gone, and how to keep it from happening again: that's the rest of this page.
Inside the engine: what petrol in a diesel really does
On its way through a motor, diesel does two tasks. Lubricating comes before burning; it does both. Very fine tolerances are built into your injectors and the high-pressure pump, and just your diesel flowing through stops those surfaces grinding together.
Petrol handles the first task poorly and the second not at all. A pump running on a petrol mixture is wearing itself out, because petrol is runnier than diesel and strips out the lubrication your fuel system relies on. Petrol is also made to resist igniting under compression — the reverse of what a diesel wants from its fuel — and that's where the knocking comes.
Put those together and the shape of the issue is clear. Contact does not do the harm — movement does. All a tank with petrol in it amounts to is a fuel issue. After your pump has been running on that petrol, a mechanical fault has started: anything shed by a pump that's wearing down is carried downstream to the fuel injectors with your fuel.
Petrol in a diesel around Greenhill: how serious is it? Four cases
The best case there is: filled up, never started. The petrol is in that tank and just the tank, and the job is a drain and a flush where your car stands. This is the one situation that can only truly take place at a forecourt, because anywhere else the car has been driven to get there.
A brief spell of running, or merely the ignition on. Once primed, the system has drawn petrol from the tank up to your filter and the fuel lines. Drain, flush, see to the fuel filter: still normally easy.
Driven a few miles. Now the pump has spent those miles working on diluted fuel. The work is that tank, the lines, your filter and clean fuel through the entire circuit, and how hard your car was driven counts as much as how far. Short trips, like the school run to St Thomas of Canterbury School, a Catholic Voluntary Academy, are one matter. Driving as far as Sheffield, under 5 miles away, makes a very different task — as does any miles on the M1, under 10 miles from Greenhill, with your engine labouring hard all the way.
Driven until it complained. Knocking, an uneven idle, smoke, a throttle that has gone soft. That's your motor telling you its fuel no longer is acting like diesel. Stop wherever you are — the verge on Greenhill Avenue, a lay-by, a side street — then leave the vehicle where it is. The drain and flush still go first, and they deal with it: when a vehicle is pulled over early, lasting damage is very rare.
Stories Greenhill drivers hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. A bigger tank of the same mix is all you get, since topping up removes nothing. A diesel fuel system does not tolerate petrol by percentage in the way that guidance presumes.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. Smaller components and higher pressure are the way a modern diesel runs its fuel, and that makes the lubrication count more, not less.
The myth that catches motorists out: if it starts and drives, it must be unharmed. Diesel in a petrol motor normally leaves a motor that will not run: the motorist stops, and so does the damage. A diesel fed petrol normally starts, idles and drives away as though nothing has happened, whilst your pump wears. Running isn't the same as fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an old fix for a distinct problem. It doesn't put back what petrol has weakened, and the petrol is still inside your tank later on.
The next start sends petrol back round your pump from the lines and the filter, where some of it ends up once your engine has run. That is why a DIY tank drain does not leave you sorted — a myth. It is also really hazardous to drain petrol into a can by the roadside.
How it happens: petrol in a diesel
Nobody does it on purpose, and it is seldom carelessness. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle generally will not go into a petrol vehicle at all. So the mistake runs one way.
When routine and the vehicle stop matching, it happens. Courtesy car, hire car, or a motor that is brand new. Households running one of each, petrol and diesel. The pumps in a different order on a familiar forecourt. A train to catch, and a hurried fill on the way to Dore & Totley. A new-to-you diesel Renault Clio, its first fuelling, and a driver used to petrol: precisely when it occurs. With rain, a call arriving, or children to deal with, the hand simply does what it has always done.
Next time you fill up in Greenhill: avoiding petrol in a diesel
- The label is what matters, so read the pump rather than the colour: in the UK unleaded handles are usually green and diesel black, yet not on each forecourt.
- Inspect your filler flap. Many vehicles state the fuel type inside the flap or on the cap. Look at it on your first fill in a car you don't know.
- Mark your key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of intending to remember.
- It sounds silly and it works: on the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump.
- Put 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 refuse a petrol nozzle, and devices you can add are available for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Noticing it halfway? Stop at once. A weaker mixture results from less petrol inside your tank, but the next step remains the same: do not crank it.
Petrol already in a diesel in Greenhill? Start here
In that case, there's just a short order of things. Never fire it up, and don't turn the ignition on. If you're still at the forecourt — BP or anywhere else — ask the staff to help you push the car clear of the petrol pump. Then ring 0333 366 0103 and tell us what got in, about how much, and if it has run.
If it was AdBlue rather than petrol, say so. That's a separate issue — corrosion and deposits and not lost lubrication — and it has its own page for Greenhill.
One petrol in a diesel task around Greenhill costs more than another. Why?
An honest single price doesn't exist here: four scenarios, four separate jobs. What shifts the cost is chiefly which of them you're in. Where your car is counts too, and whether our van can safely get to it, after the share of petrol to what the tank takes.
That is why our technicians ask three questions before quoting rather than after: what was put in, how much, and if it has run. Those answers are what turn a range into one firm number.
About Greenhill itself
Greenhill is a suburban area situated on the riverside in South Yorkshire, with an elevation of around 180 metres. Greenhill lies approximately 3.7 miles from Sheffield city centre and is surrounded by nearby places such as Little Norton, Meadow Head, and Lowedges. Greenhill has a population of around 5239 people and predominantly features semi-detached housing. Greenhill is located about 138.2 miles north of London, in the Yorkshire and the Humber region.
Across South Yorkshire and around Greenhill: fuel drain cover
Petrol in diesel jobs around Greenhill — part of the S postcode area — go to teams that also cover the locations round it, Little Norton, Meadow Head and Lowedges among them. No need to bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations where we work.
Greenhill: still at the pump?
The best position there is, then — that's where you are. Keep it off. Phone.