How Worried Should You Be? Petrol in a Diesel Car in Knowle Grove
Not started? Then less anxious than you probably feel. Petrol resting in a diesel tank does nothing to the motor until something draws it through the fuel system — the ignition priming your pump, the starter, or the drive itself. So the truthful answer to the first question everyone in Knowle Grove asks, "have I wrecked it?", is usually no. Keep it that way: leave the motor off and 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's the remainder of this page.
Petrol in a diesel: what does it do to the engine?
Passing through an engine, diesel is doing two jobs at once. It lubricates first, and only then does it burn. Very fine clearances go into the injectors and your high-pressure pump, and only the diesel flowing through keeps those surfaces from grinding together.
The second task petrol does not do at all, and the first it does badly. It is thinner than diesel and removes the protection your fuel system hinges on, and 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 is where the rattling comes from.
Put those together and the shape of the problem is clear. The harm is done by movement, not by contact. A tank with petrol in it is a fuel fault. Whatever a worn pump sheds goes on, carried by your fuel, into your injectors downstream, which is why a pump that has been working on the petrol is where a mechanical fault starts.
How serious is petrol in a diesel? Four situations our technicians see in Knowle Grove
The best case there is: filled up, never started. Only that tank has petrol in it, so the task is clearing the tank and purging the fuel system where the vehicle stands. This situation can only really occur at a forecourt: anywhere else, your car got there by being driven.
The ignition turned on, or a brief start. With your system primed, your lines and filter already contain petrol that has come from the tank. Drain, flush, see to your filter: still usually straightforward.
Driven a couple of miles. Now your pump has spent those miles running on thinned fuel. Tank, lines, filter, then clean fuel run through the entire system: that is the work, and the way the vehicle was driven matters as much as the miles. On the school run to Trumps Green Infant School, the distance is small. A run as far as Westminster, under 25 miles away, is a very different job. So is any miles on the M3, under a mile from Knowle Grove, where your engine has been working hard throughout.
Driven on till it protested — knocking, smoke, an uneven idle, a dead throttle. What you are hearing is the motor reporting fuel that no longer behaves like diesel. Whether it's the verge on Trumps Green Road, a lay-by or a side road, stop where you are and leave it. The drain and flush still come first, and they take care of it: if a vehicle is stopped soon, long-term damage is very uncommon.
What Knowle Grove people get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Topping up takes out nothing; it gives you a fuller tank of the same mixture. That advice assumes a diesel fuel system handles petrol by percentage. It doesn't.
Myth: a newer diesel copes with a bit of petrol. Rather, the opposite. Lubrication counts more on newer diesels, not less, since their fuel passes through smaller parts at higher pressure.
This is the one that fools drivers. Myth: "If it starts and drives, there is no harm done." Diesel in a petrol motor normally means a motor that won't run: the motorist stops, and so does the harm. Whilst the pump wears, a diesel fed petrol normally starts, idles and drives away as if nothing has happened. Fine and running are not the same at all.
An outdated fix for a distinct problem is behind this one. Myth: "Add some two-stroke oil and drive the car home." That petrol is still inside your tank after that, and whatever it has weakened isn't put back.
The next start draws petrol back round the pump from the lines and your filter, where some of that sits after your engine has been run. That's why a DIY tank drain does not leave you sorted — a myth. On top of that, petrol drained into a can by the road is truly risky.
How does petrol in a diesel occur?
It's rarely carelessness, and no one does it on purpose. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one mostly will not fit a petrol car. That's how the forecourt makes it easy.
The moment routine stops matching the vehicle is the moment it happens. Hire cars, courtesy cars, and motors that are new to you. A household with one petrol and one diesel on the driveway. Your ordinary forecourt, its pumps now in a different order. A train to catch, and a rushed fill on the way to Longcross. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. Add rain, a phone call or a back seat full of children, and your hand repeats what it has always done.
Preventing petrol in a diesel next time you fill up around Knowle Grove
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most generally do. Read the petrol pump's label; the colour is just a hint.
- The first fill in an unfamiliar car is the time to check the filler flap — on it, or on the cap, plenty of cars state the fuel they take.
- Good intentions do less than a sticker or a fob in a bright colour on the diesel's key when a home has one of each. So label it.
- It sounds daft and it does the trick: on your first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump.
- While you're thinking about something else, this is an easy mistake to make — so put your phone away.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to block a petrol nozzle, and aftermarket devices exist for the rest. Treat it as a safety net, then keep reading the pump.
- The moment you realise, stop: less petrol inside the tank makes a weaker mix. What to do next does not change, though — still don't start the vehicle.
Already put petrol in a diesel in Knowle Grove?
Then the order of things is brief. Never fire it up, and don't turn your ignition on. If you are still on the forecourt — Shell or anywhere else — ask the staff to help you push the car clear of the petrol pump. Next, 0333 366 0103. We will ask what got in, about how much, and if it's been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate fault — Knowle Grove has a page all for it.
What makes one Knowle Grove petrol in a diesel task cost more than the next
Four different jobs sit behind the four situations above — which is why there is no fair single price. What shifts the cost is chiefly which of them you're in. Where the car is counts too, and whether our van can safely get to it, after the proportion of petrol to what the tank takes.
Before any quote, not after, come three queries: your fuel that went in, its amount, and if it's run. That is why. With the replies, you get a straight figure instead of a range.
About Knowle Grove
Knowle Grove is a suburban area in Surrey, situated inland at an elevation of 59 metres, and is located approximately 20.9 miles from London. Knowle Grove forms part of a network of residential communities in the area, including nearby Knowle Hill, Harpesford, and Trumps Green. Knowle Grove is characterized by its predominantly detached housing stock, reflecting the area's residential development patterns.
Knowle Grove and Surrey: where our fuel drain cover reaches
Knowle Hill, Harpesford and Trumps Green are among the spots near Knowle Grove that the same vans work, answering petrol in diesel call-outs across Knowle Grove's GU postcode area. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations our engineers work, and your vehicle does not need to move to us.
Still at the pump in Knowle Grove?
Then, you couldn't be in a better place. Keep it off. Phone.