Greatpark: Petrol in a Diesel Car? How Worried to Be
Probably less than you are now — as long as no one has started the car. Everyone around Greatpark begins with "have I wrecked it?", and the honest answer is usually no: petrol resting inside the tank of any diesel stays harmless until priming, cranking or driving draws it into your fuel system. To leave it like that, ring Petrol in Diesel and leave the engine switched off. What petrol actually does to a diesel, how to judge how far it has gone, and how to stop it from happening a second time: that is the rest of this page.
Petrol in a diesel: what does it do to the engine?
Two tasks fall to diesel on its journey round a motor. Before it burns, it protects — then it burns. The high-pressure fuel pump and the fuel injectors are made to very fine clearances, and the diesel passing through them is what stops those surfaces from grinding against each other.
Petrol does the first task poorly and the second not at all. The clattering comes from petrol being made not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection the fuel system hinges on, and any pump running on such a mix is wearing itself.
Put these together and the shape of the issue is clear. It is movement that causes the harm, not contact. A tank with petrol in it is a fuel issue. Whatever a worn pump sheds goes on, borne by the fuel, into your injectors further along, which is why a pump that has been working on the petrol is where a mechanical fault begins.
Greatpark, petrol in a diesel: four situations, from mild to serious
Fuelled up, never started. The best case there can be. On a forecourt, and really only there, the petrol is still confined to that tank — because everywhere else your car was driven to reach it. The job is draining and cleaning on the spot.
Started for a second, or just the ignition on. Once primed, the fuel system has pulled petrol out of the tank as far as the fuel filter and your lines. Drain, flush, see to the fuel filter: still usually simple.
A few miles driven, and the pump has spent each of them running on thinned fuel. Distance is only half of it; how hard it was driven matters equally. Either way the work includes that tank, the lines, the fuel filter and clean fuel through the entire system. Short trips, such as the school run to Warlingham Village Primary School, are one matter. A run as far as Westminster, under 15 miles away, is a very different job. So is any distance on the M25, under 5 miles from Greatpark, where your engine has been working hard throughout.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. What you are hearing is the motor reporting fuel that no longer behaves like diesel. Stop wherever you are — the verge on Lodge Walk, a lay-by, a side street — then leave the vehicle where it is. A car stopped soon very rarely has lasting damage, since the drain and the flush-through, which still go first, deal with it.
What Greatpark drivers get told about petrol in a diesel — and the stories in it
Myth: topping up to full with diesel makes it fine. It doesn't. Topping up removes nothing; it gives you a bigger tank of the same mixture. Percentage is not how a diesel fuel system tolerates petrol, whatever that guidance presumes.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." Smaller components and higher pressure are how a modern diesel runs its fuel, and that makes the protection count more, not less.
The myth that catches people off guard: if it starts and drives, it must be unharmed. Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the harm. Feed petrol to a diesel and it generally starts, ticks over and drives away like nothing happened — all the while its pump is wearing. Being able to run is not the same as being fine.
Myth: a two-stroke additive lets you to drive home. It was an old fix, meant for another fault. What petrol has thinned remains thinned, and the petrol stays inside that tank anyway.
"Drain it yourself and you are sorted" — a myth, since after it's been running some petrol lies in the filter and lines, ready to go straight back through your pump at the next start. And, a can of petrol drained by the roadside is truly dangerous.
Why petrol in a diesel happens at all
It is seldom carelessness, and no one does it on purpose. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly will not go into a petrol vehicle at all. The forecourt makes it easy, and the slip runs one way.
The moment routine stops matching the vehicle is the moment it takes place. Any motor that's new to you — a hire car, on loan as a courtesy car, or brand new. Two vehicles on one drive, one petrol, one diesel. Your ordinary forecourt, its pumps suddenly in a different order. Racing for a train at Woldingham and fuelling up en route. Years of petrol vehicles behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. Add rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
How to prevent petrol in a diesel at your next fill-up around Greatpark
- Read the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, yet not on every forecourt. The label is what matters.
- The first fill in a strange car is the time to check your filler flap — inside it, or on the cap, many vehicles state which fuel to use.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, for a home with one of each.
- Before the nozzle comes off the petrol pump the first time you fill a hired or new car, say "diesel" aloud. Silly, yes, yet it works.
- Mistakes like this are easy to make while your mind is on something else, so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels come with a filler designed to reject a petrol nozzle, and add-on devices exist for vehicles without one. They are a backstop, not a reason to stop checking the petrol pump.
- Spotting it halfway? Stop there and then. A weaker mix results from less petrol inside that tank, yet your next stage remains the same: do not crank it.
Greatpark: already put petrol in a diesel?
Then the order of things is brief. Starting it is out, and so is turning on your ignition. Yet on the forecourt, at Warlingham Service Station or anywhere else? Ask the staff to help you roll the car clear of the pump. Phone 0333 366 0103 next, with three answers — your fuel, the rough volume, and if it has run.
If it was AdBlue instead of petrol, say so. That is a different fault — corrosion and deposits rather than lost protection — and it has its own page for Greatpark.
One petrol in a diesel job around Greatpark costs more than another. Why?
An honest single price does not exist here: four situations, four separate tasks. The scenario itself does most of the work of moving the cost. Two things come after that: the petrol that got in as a share of what that tank holds, then the place the vehicle is in and whether our van can reach it safely.
Three queries come first, before quoting, rather than after — what went in, how much, has it run — and that is the reason. Their replies are what turn a range into one firm number.
About Greatpark
Greatpark is a suburban area in Surrey, situated inland at an elevation of 184 metres, and is located approximately 13.8 miles from London. Greatpark has a population of around 535 people and is characterised by predominantly detached housing. Greatpark is near several other places, including Chelsham, Farleigh Court, and Farleigh, and is close to the city of Westminster, which is about 13.4 miles away.
Across Surrey and in Greatpark: fuel drain cover
Our vans answering petrol in diesel call-outs around Greatpark, in the CR postcode area, also work the places around it, Chelsham, Farleigh Court and Farleigh among them. The car does not need to come to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Greatpark: still at the pump?
Then, you couldn't be in a better place. Turned off it remains; then ring.