Bledlow Ridge: Petrol in a Diesel Car? How Worried to Be
Less than you likely are, if it has not been started. Everyone around Bledlow Ridge starts with "have I ruined it?", and the honest answer is generally no: petrol left inside the tank of any diesel remains harmless until priming, cranking or driving pulls it into the fuel system. Keep it that way: leave your motor off and phone Petrol in Diesel. Further down, this page sets out what petrol really does inside a diesel, how far it might have gone, and how to stop it happening to you again.
What petrol in a diesel does to the motor
Passing through a motor, diesel is doing two jobs at the same time. It burns, and before it ignites it protects. Very fine clearances are built into your injectors and your high-pressure pump, and only your diesel running through stops their surfaces grinding together.
Petrol does the first task poorly and the second not at all. The clattering comes from petrol being designed not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication the fuel system rests on, and any pump working on that blend is wearing itself.
Put these together and the shape of the problem is clear. The damage is done by movement, not by contact. A tank with petrol in it is a fuel fault. The start of a mechanical problem is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Petrol in a diesel in Bledlow Ridge: how serious is it? Four situations
Filled up, never started. The best case there is. Being on a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With that petrol held in that tank alone, it is emptied and flushed right where it stands, and nothing more is needed.
The ignition switched on, or a brief start. With the system primed, your lines and filter now contain petrol that has come from the tank. That's normally still an easy task — a drain, a flush, and your filter dealt with.
Those few miles driven were the pump labouring on fuel weakened by petrol the whole way. Mileage is only half of it; how hard it was driven matters just as much. Either way this work runs to that tank, your lines, your filter and fresh fuel through the whole system. On the school run to Bledlow Ridge School, the distance is small. Very different a second time: a trip to Oxford, under 25 miles away, or any mileage on the M40, under 3 miles from Bledlow Ridge, where the engine never stopped running hard.
Driven on until it complained — knocking, smoke, an uneven idle, a soft throttle. The motor is telling you your fuel is no longer acting like diesel. Stop where you are — on the verge on Ford's Close, at the kerb, down a side road — and don't move it again. A vehicle pulled over quickly very seldom has permanent damage, because the fuel drain and the flush-through, which still come first, sort it out.
What Bledlow Ridge people get told about petrol in a diesel — and the myths in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Topping up removes nothing; it gives you a fuller tank of the same mixture. The assumption behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the reverse. Smaller components and higher pressure are how a modern diesel runs its fuel, and that makes the protection matter more, not less.
"It starts, it drives, and so there is no harm" — the myth that trips up most people than any other. Feed diesel to a petrol engine and it usually won't run, and so the driver stops — and the damage stops with them. Feed petrol to a diesel and it usually fires up, idles and drives away like nothing has happened — all while its pump wears. Running does not mean fine.
An outdated fix for a separate problem is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has weakened stays weakened, and that petrol stays inside that tank anyway.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol sits in the filter and lines, waiting to go right back through your pump at your next start. It's also truly risky to drain petrol into a can by the kerbside.
How does petrol in a diesel take place?
On purpose? Never. Through carelessness? Seldom, if ever. A diesel nozzle mostly won't go into a petrol motor, but the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake easy, and only in that direction.
When routine and your car stop matching, it takes place. A new vehicle, a hire car or a courtesy car. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps arranged differently. A rushed fill en route to Saunderton with a train to catch. Precisely the moment it occurs: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
Next time you fill up in Bledlow Ridge: preventing petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, but not on every forecourt. The label is what counts.
- Plenty of cars state the fuel inside the filler flap or on the cap, and so check it on the first fill in any vehicle you do not know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of intending to remember, in a house with one of each.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car gets its first tank. It sounds silly. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so tuck your phone away and keep your mind on the petrol pump.
- Add-on devices exist for motors without one, and some diesels are built with a filler that won't take a petrol nozzle. Helpful — but a backstop only, never a reason to stop checking the label.
- As soon as you realise, stop: less petrol inside that tank makes a thinner blend. What to do next doesn't change, though — still don't crank it.
Petrol already in a diesel around Bledlow Ridge? Begin here
Then the order of things is brief. Don't switch the ignition on, and don't crank it. If you're still on the forecourt — Shell or anywhere else — ask the attendants to help you push it clear of the pump. What went in, roughly how much, and if it's run: tell us that when you ring 0333 366 0103.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a separate problem — Bledlow Ridge has a page all for it.
One petrol in a diesel task in Bledlow Ridge costs more than another. Why?
Four different jobs lie behind the four scenarios above — which is why there is no fair single quote. What moves your cost is mostly which of them you're in. Where your car is matters too, and whether our van can safely get to it, after the ratio of petrol to what the tank holds.
Ahead of any quote, not after, we ask three queries: your fuel that went in, its amount, and whether it has run. That's why. With the answers, you get a straight figure rather than a range.
About Bledlow Ridge, for a moment
Bledlow Ridge is a village in Buckinghamshire, situated in the Chiltern Hills at an elevation of 206 metres. Bledlow Ridge lies approximately 33 miles west of London and 18 miles southeast of Oxford, near the villages of Radnage and Routs Green. Bledlow Ridge is characterised by its predominantly detached housing stock and rural setting. Bledlow Ridge has a population of around 804 residents.
Bledlow Ridge and Buckinghamshire: where our fuel drain cover runs
Bledlow Ridge waits in the HP postcode area, and our teams that answer petrol in diesel jobs there work the locations near it as well — Radnage, Routs Green and The City among them. The car doesn't need to come to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
In Bledlow Ridge and still at the pump?
Nothing beats it: that is where you now are. Switched off it remains; then call.