Buckden: Petrol in a Diesel Car? How Worried to Be
Provided it has not been started, you can worry less than you likely are. Everyone in Buckden begins with "have I ruined it?", and the honest answer is generally no: petrol resting inside that tank of any diesel remains harmless until priming, cranking or driving draws it into the system. Keep it like that: leave your motor off and call Petrol in Diesel. What petrol really 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.
Petrol in a diesel: what does it do to the engine?
On its way through an engine, diesel has two jobs. Lubricating comes before burning; it does both. What keeps the surfaces inside the high-pressure pump and your injectors from wearing against one another is your diesel flowing through them — they are made to very fine tolerances.
Badly at the first, not at all at the second: that's petrol. The knocking comes from petrol being made not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication your system rests on, and any pump working on that blend is wearing itself.
The shape of the trouble is plain when you put those together. Not contact but circulation is what causes the harm. All a tank with petrol in it amounts to is a fuel problem. The beginning of a mechanical one is a pump that has been running on that petrol — and whatever a worn pump sheds travels on with the fuel to the fuel injectors downstream.
How bad is petrol in a diesel? Four situations our technicians see in Buckden
The best case there can be: filled up, not once started. Being at a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol held inside your tank alone, it's cleared and cleaned on the spot, and nothing more is needed.
The ignition switched on, or a short start. Once primed, the system has drawn petrol from your tank as far as the fuel filter and the lines. Still normally simple: drain, flush, and your filter dealt with.
Driven a couple of miles. Now your pump has spent those miles running on thinned fuel. How hard the car was driven counts as much as how far, and the work takes in your tank, the fuel lines, the fuel filter and clean fuel through the entire circuit. The school run to Buckden CofE Primary School is one thing. Any mileage on the A1(M), under 5 miles from Buckden, means your engine working hard throughout, and a run to Cambridge, under 25 miles away, makes a very different task too.
It complained, and only then stopped: smoke, rattling, a throttle gone soft, an idle gone lumpy. The motor is telling you your fuel is no longer acting like diesel. Stop wherever you are — the verge on High Street, a lay-by, a side street — then leave the vehicle there. A vehicle pulled over soon very rarely has long-term damage, as the fuel drain and the flush, which still come first, sort it out.
Petrol in a diesel stories Buckden people hear
Myth: topping up to full with diesel makes it fine. It does not. Topping up takes out nothing; it gives you a fuller tank of the same mix. That advice presumes a diesel fuel system tolerates petrol by percentage. It doesn't.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. More precise parts and higher pressure are how a newer diesel runs its fuel, and that makes the protection matter more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there is no harm done." Any petrol engine fed diesel usually will not run, and so the motorist stops and the damage stops with them. Whilst your pump grinds, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Running does not mean fine.
An old workaround for a separate issue is behind this one. Myth: "Add some two-stroke oil and drive it home." It does not put back what petrol has diluted, and that petrol is still inside the tank afterwards.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol sits in the fuel filter and lines, ready to go straight back through the pump at your next start. Also, a can of petrol drained by the roadside is truly dangerous.
Petrol in a diesel: how does it occur?
It is seldom carelessness, and no one does it on purpose. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol vehicle at all. The forecourt makes it simple, and the mistake runs one way.
It takes place when habit and the car stop matching. Courtesy car, hire car, or a vehicle that is brand new. One petrol and one diesel on the driveway of the same household. A familiar forecourt with the pumps in a different order. A rushed fill en route to Huntingdon with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a motorist accustomed to petrol: exactly when it occurs. The hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
Buckden people: how to avoid petrol in a diesel next time
- Check the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, but not on every forecourt. The label is what counts.
- In a motor you don't know, look inside the flap over the filler or at the cap before the first fill: many vehicles print the fuel type there.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of intending to remember, in a home with one of each.
- Before the nozzle leaves the pump the first time you fill a hired or new vehicle, say "diesel" aloud. Silly, yes, but it does the trick.
- Tuck the phone away. This is an easy mistake to make whilst you are thinking about something else.
- Add-on devices exist for motors without one, and some diesels come with a filler that won't take a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label.
- Spotting it mid-fill? Stop there and then. A weaker mixture follows from less petrol in the tank, but the next stage stays the same: don't start the vehicle.
Put petrol in a diesel in Buckden already?
In that case, there is only a short order of things. Do not start the vehicle, and do not turn the ignition on. Ask the attendants to help you roll it away from the petrol pump if you are still at the forecourt, whether that's Shell or somewhere else. Next, 0333 366 0103. We will ask what got in, about how much, and if it has been run.
Corrosion and deposits are the issue with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and see its own Buckden page.
One petrol in a diesel job around Buckden costs more than another. Why?
The four scenarios above are four separate jobs, so no single quote for this would be honest. What shifts the cost is mostly which of them you are in. The ratio matters next, meaning how much of that tank is petrol, followed by the location of the car and whether getting to it is safe for our van.
Ahead of any quote, not after, come three questions: the fuel that was put in, its amount, and whether it's run. That is why. A range turns into a straight figure once the answers are in.
About Buckden and its setting
Buckden is a village in Cambridgeshire, situated on the lakeside at an elevation of 29 metres, with detached housing being the predominant type of accommodation. Buckden lies near the villages of Hardwick, Stirtloe, and Diddington, and is approximately 17 miles from Cambridge. Buckden has a population of around 1570 residents and is about 54.6 miles from London. Buckden enjoys a peaceful setting, surrounded by the Eastern region's countryside.
Fuel drain cover around Buckden and across Cambridgeshire
Hardwick, Stirtloe and Diddington are among the locations around Buckden that the same teams work, answering petrol in diesel jobs across Buckden's PE postcode area. Our engineers drain where the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
In Buckden and still at the petrol pump?
No position is better: that is where you now are. Switched off it remains; then phone.