West Ewell: Petrol in a Diesel Car? How Worried to Be
Far less than you probably are, provided it has not been started. "Have I wrecked it?" is the first question everyone in West Ewell asks, and the truthful answer is usually no, since petrol left in a diesel tank harms nothing till it is drawn through the system — by ignition priming, by your starter, or by being driven. Leave the engine off then phone Petrol in Diesel — that keeps it that way. Further down, you will find what petrol really does inside a diesel, how far it may have got, and how to stop it happening to you again.
Petrol in a diesel: what does it do to the engine?
Diesel has two jobs on its way through a motor. Before it ignites, it lubricates — then it combusts. The high-pressure pump and the injectors are designed to very fine gaps, and the diesel passing through them is what stops those surfaces from wearing down against each other.
Poorly at the first, not at all at the second: that's petrol. The clattering 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 away the protection your system rests on, and any pump running on that mixture is wearing itself.
The shape of the problem is clear when you put those together. Contact does not do the damage — circulation does. All a tank with petrol in it amounts to is a fuel problem. The start of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors beyond it.
West Ewell, petrol in a diesel: four cases, from mild to serious
Filled up, never started. The best case there is. On a forecourt, and truly only there, the petrol is still limited to your tank — because everywhere else the vehicle was driven to reach it. The job is emptying and purging on the spot.
Ignition on, or started for a moment. With the fuel system primed, the fuel lines and filter already contain petrol that came from that tank. Drain, flush, see to your filter: still normally straightforward.
The pump now spent a few miles on weakened fuel — that is what driving the car meant. Tank, lines, filter, then fresh fuel run through the whole system: that is the work, and the way the vehicle was driven counts as much as the mileage. On the school run to Danetree Primary School, the miles is short. Any mileage on the M25, under 5 miles from West Ewell, means your engine has worked hard throughout, and a run to Westminster, under 15 miles away, makes a very different task too.
Clattering, a ragged idle, smoke, a throttle gone soft: driven till it complained. The fuel isn't acting like diesel any more, and the motor is saying so. Stop wherever you are — the verge on Chessington Road, a lay-by, a side street — then leave the vehicle where it is. The drain and flush-through still come first, and they deal with it: when a car is pulled over quickly, long-term damage is very uncommon.
Myths West Ewell people hear about petrol in a diesel
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing is removed by topping up — you're left with a fuller tank, still the same mix. The idea 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 reverse. A modern diesel sends its fuel through smaller parts at higher pressure, which makes the protection matter more, not less.
The myth that catches drivers off guard: if it starts and drives, it must be unharmed. A petrol engine fed diesel generally won't run, and so the driver stops and the harm stops with them. A diesel fed petrol usually starts, idles and drives away as if nothing has happened, while your pump grinds. Running is not the same as fine.
Not so: a two-stroke additive lets you to drive home. It was an old workaround, meant for another fault. That petrol is still in the tank afterwards, and what it has weakened is not put back.
The next start draws petrol back round the pump out of the lines and your filter, where some of it sits after your engine has been run. That's why draining your tank yourself doesn't sort it — a myth. On top of that, petrol emptied into a can by the road is genuinely dangerous.
How does petrol in a diesel happen?
A careless moment is rarely the cause, and nobody means to do it. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle mostly will not go into a petrol motor at all. So the slip runs one way.
The moment habit stops matching the vehicle is the moment it happens. Any vehicle that's new to you — a hire car, on loan as a courtesy car, or just bought. Two cars on one driveway, one petrol, one diesel. A well-known forecourt with the pumps in a different order. A rushed fill on the way to Ewell West with a train to catch. The first fill-up in a diesel Volkswagen Passat after years of driving petrol is exactly the moment it happens. Add a back seat full of children, a phone call or rain, and the hand takes over.
Next time you fill up in West Ewell: preventing petrol in a diesel
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Check the pump's label; the colour is only a clue.
- In a car you don't know, look inside the flap over your filler or at the cap before your first fill: plenty of vehicles print the fuel there.
- One of each in the house? Label the key to your diesel — a coloured fob, a sticker — because intending to remember isn't enough.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new vehicle, say "diesel" aloud. Silly, yes, but it does the trick.
- Mistakes like this are straightforward to make whilst your mind is on something else, and so your phone goes away.
- Add-on devices are available for cars without one, and some diesels are built with a filler that will not accept a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label.
- Less petrol makes a thinner mix, so stop as soon as you notice — while remembering that your next stage is unchanged. It's still not to crank it.
Already put petrol in a diesel around West Ewell?
The order of things is short, then. Never start it, and do not turn your ignition on. If you are still on the forecourt — Texaco or anywhere else — ask the staff to help you roll it away from the petrol pump. Then phone 0333 366 0103 and tell us what went in, roughly how much, and if it's run.
Say so if it was AdBlue instead of petrol: it is a different issue, with its own page for West Ewell, because AdBlue brings corrosion and deposits instead of lost lubrication.
Why one petrol in a diesel job around West Ewell costs more than another
The four scenarios above are four different jobs, so no single quote for this would be honest. Chiefly, the cost moves with which situation you're in. The share counts next, meaning how much of that tank is petrol, and then the position of your car and whether reaching it is safe for a technician.
Three queries come first, before any quote, rather than after — what went in, how much, has it run — and that is the reason. A range becomes a straight figure once the replies are in.
About West Ewell itself
West Ewell is a suburban area in Surrey, situated near the River Hogsmill and close to the borough of Epsom and Ewell. West Ewell lies approximately 12 miles south-west of central London, with Westminster around 11.8 miles away. West Ewell has a mix of housing types, but semi-detached homes are predominant in the area. West Ewell is near several local parks and green spaces, including Livingstone Park.
Across Surrey and in West Ewell: fuel drain cover
Livingstone Park, Stoneleigh and Ewell are among the spots around West Ewell that the same vans work, answering petrol in diesel call-outs across West Ewell's KT postcode area. A forecourt, a supermarket car park, a lay-by or your own drive are all spots we drain, and your car doesn't need to move to us.
Still at the petrol pump in West Ewell?
Then you are in the best spot there can be. Leave the vehicle switched off, then ring.