Dunsfold Green: Petrol in a Diesel Car? How Worried to Be
Not started? Then less worried than you likely feel. Until your ignition primes the pump, the starter cranks, or your car is driven, petrol in a diesel tank just rests there and does no harm. Which makes the truthful reply to that first Dunsfold Green question — "have I ruined it?" — normally no. Petrol in Diesel is who to phone, with your motor left off, so it remains that way. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and ways to make sure you never do it again.
What petrol in a diesel does to the motor
Passing through a motor, diesel is doing two jobs at the same time. Lubricating comes before burning; it does both. What stops the surfaces inside your high-pressure pump and the injectors from wearing down against each other is your diesel flowing through them — they are designed to very fine tolerances.
Petrol handles the first task poorly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so a pump on that mixture to wear itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the knocking.
Together, those make the shape of the issue plain. It's circulation that does the harm, not contact. Petrol in a tank is a fuel problem. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the fuel injectors further on.
Petrol in a diesel around Dunsfold Green: how serious is it? Four cases
Filled up, never started. The best case there can be. Being on a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol kept inside the tank alone, it is drained and flushed on the spot, and nothing more is needed.
A moment's running, or just your ignition on. Petrol has come out of your tank and reached your filter and the lines, because the fuel system has been primed. Drain, flush, deal with your filter: still usually easy.
Driven a couple of miles. Now your pump has spent those miles running on diluted fuel. How hard the vehicle was driven matters as much as how far, and the work takes in that tank, your lines, your filter and clean fuel through the entire circuit. Driving the children to St Mary's Church of England Primary School is one kind of trip. Driving as far as Chichester, under 25 miles away, makes a very different task — as does any mileage on the M25, under 15 miles from Dunsfold Green, with the motor working hard all the way.
Rattling, a ragged idle, smoke, a throttle gone soft: driven till it complained. That's your engine telling you its fuel has stopped behaving like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Nugent Close. Long-term damage is very uncommon if a car is stopped soon, and the fuel drain and flush that still go first sort it out.
Myths Dunsfold Green drivers hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed when you top up — the tank simply holds more of the same blend. The assumption behind the guidance — that diesel fuel systems accept petrol by percentage — is wrong.
"Current diesels can handle a little petrol" — a myth, and closer to the opposite. Smaller components and higher pressure are the way a modern diesel runs its fuel, and that makes the protection count more, not less.
"It starts, it drives, and so no harm done" — the myth that catches most people than any other. Diesel in a petrol motor usually leaves a motor that will not run: the driver stops, and so does the damage. Whilst your pump grinds, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Fine and running are not the same at all.
An outdated fix for a distinct fault is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has thinned stays thinned, and the petrol remains inside that tank regardless.
Once the engine has run, part of the petrol is in the filter and the fuel lines, not that tank — and the next start pulls it straight back through the pump. So the myth "drain that tank yourself and you're sorted" does not hold. And, a can of petrol filled at the roadside is genuinely hazardous.
How petrol ends up: petrol in a diesel
Carelessness is seldom the cause, and nobody means to do it. A diesel nozzle mostly will not go into a petrol vehicle, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake easy, and only in that direction.
It happens when routine and the car stop matching. A car that is new to you — a hire car, on loan as a courtesy car, or brand new. Two cars on one drive, one petrol, one diesel. A well-known forecourt with the pumps in a different order. Filling up in a hurry en route to Witley, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist used to petrol: precisely when it occurs. The hand does what it has always done when you add rain, a phone call or a back seat full of kids.
Next time you fill up around Dunsfold Green: preventing petrol in a diesel
- Read the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, but not on each forecourt. The label is what counts.
- Check your filler flap. Plenty of vehicles state the fuel type inside the flap or on the cap. Look at it on your first fill in any car you do not know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of intending to remember, for a household with one of each.
- It sounds silly 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 pump.
- Whilst you're thinking about something else, this is an easy mistake to make — so put the phone away.
- Add-on devices exist for vehicles without one, and some diesels come with a filler that will not take a petrol nozzle. Helpful — but a safety net only, never a reason to stop checking the label.
- Noticing it halfway? Stop there and then. A thinner mixture results from less petrol in your tank, but the next step remains the same: don't crank it.
Petrol already in a diesel in Dunsfold Green? Start here
Short and simple, then, is the order of things. Don't turn the ignition on, and don't fire it up. Ask the staff to help you roll it away from the petrol pump if you are still on the forecourt, whether that's BP or somewhere else. What went in, about how much, and whether it's run: tell us that when you ring 0333 366 0103.
If it was AdBlue instead of petrol, say so. That's a separate problem — corrosion and deposits and not lost lubrication — and it has its own page for Dunsfold Green.
Why one petrol in a diesel task around Dunsfold Green costs more than another
The four situations above are four different jobs, so no single quote for this would be fair. Which of them you're in is chiefly what shifts the cost. After that it's the share — how much petrol got in against how much the tank takes — and then where the car is and whether a technician can reach it safely.
What was put in, how much, and whether it's run — three queries our engineers ask before pricing, not after, for precisely that reason. A range becomes a straight figure when the answers are in.
About Dunsfold Green itself
Dunsfold Green is a locality in Surrey, situated near the River Wey and surrounded by countryside. Dunsfold Green sits at an elevation of 56 metres, with Dunsfold Green being close to the villages of Dunsfold and Peartree Green. Dunsfold Green is characterized by its semi-detached housing and rural setting, with Dunsfold Green being approximately 32.8 miles from London.
Fuel drain cover across Surrey, Dunsfold Green included
Dunsfold Green waits in the GU postcode area, and our teams that answer petrol in diesel calls there work the locations around it as well — Dunsfold, Peartree Green and Dunsfold Common among them. A forecourt, a supermarket car park, a lay-by or your own drive are all spots we work, and the vehicle doesn't need to come to us.
In Dunsfold Green and still at the pump?
Nothing beats it: that's where you now are. Keep it switched off, and ring.