Should You Worry? Petrol in a Diesel Car in Woodlands
Probably less than you already are — as long as no one has started the vehicle. Till the ignition primes the pump, the starter turns, or your car is driven, petrol in a diesel tank simply rests there and does nothing. Which means the honest reply to the first Woodlands query — "have I wrecked it?" — normally no. To keep the car like that, call Petrol in Diesel then leave the motor switched off. Below, this page sets out what petrol actually does inside a diesel, how far it might have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to your engine?
Passing through an engine, diesel does two jobs at once. It lubricates to begin with, and only then does it burn. Made to very fine tolerances, your injectors and your pump depend on your diesel moving through them to stop their surfaces wearing against one another.
Of those two jobs, petrol manages the first badly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump on the blend to wear itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is where you hear the clattering.
Seen together, they show the shape the problem takes. Contact doesn't do the harm — movement does. Petrol in a tank is a fuel fault. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with the fuel to the injectors downstream.
How bad is petrol in a diesel? Four scenarios our technicians see in Woodlands
Filled up, not once started. The best case there is. The petrol is inside that tank and only that tank, and the task is a drain and a flush where your car sits. This is the one scenario that can only really take place at a forecourt, since anywhere else your car has been driven to get there.
The ignition turned on, or a short start. Your system has been primed, so petrol has left that tank and got to the fuel filter and the lines. Still usually straightforward: drain, flush, and the filter sorted.
The pump now worked a couple of miles on thinned fuel — that's what driving the car does. How hard your car was driven matters as much as how far, and this work covers the tank, the fuel lines, your filter and clean fuel through the entire system. On the school run to Sun Hill Infant and Preschool, the miles is short. Any distance on the M3, under 5 miles from Woodlands, means the motor has worked hard throughout, and a run to Winchester, under 10 miles away, makes a very different job as well.
Clattering, a ragged idle, smoke, a throttle gone soft: driven till it complained. The engine is telling you your fuel is no longer acting like diesel. Pull up on the spot — on the verge on Winchester Road, at the kerb, down a side road — and do not move it. The fuel drain and flush-through still come first, and they deal with it: if a car is stopped early, lasting damage is very uncommon.
Woodlands people and that petrol in a diesel stories they hear
Myth: topping up to full with diesel makes it fine. It does not. Nothing comes out when you top up — that tank just holds more of the same mixture. 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 nearer the reverse. Lubrication matters more on newer diesels, not less, since their fuel passes through smaller parts at higher pressure.
Myth: "If it starts and drives, there's no harm done." This is the one that catches people. The motorist of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the harm stops there. Feed petrol to a diesel and it generally fires up, idles and pulls away like nothing has happened — all the while its pump is wearing. A running engine doesn't mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a separate problem. The petrol is still inside the tank after that, and what it has thinned is not put back.
Once the engine has been run, part of that petrol is in the fuel filter and the lines, not the tank — and your next start pulls it right back through the pump. So the myth "drain your tank yourself and you're sorted" doesn't stand up. Clearing petrol into a can by the kerbside is also truly dangerous.
How it happens: petrol in a diesel
A careless moment is seldom the cause, and no one means to do it. 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 motor at all. The forecourt makes it simple, and the mistake runs one way.
The moment routine stops matching your car is the moment it happens. A new vehicle, a hire car or a courtesy car. Households running one of each, petrol and diesel. A familiar forecourt with the pumps in a different order. Racing for a train outside Winchester and fuelling up en route. Years of petrol motors behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that is when. Your hand repeats 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 Woodlands: avoiding petrol in a diesel
- Green for unleaded and black for diesel is usual in the UK — but not on every forecourt. Go by the label on the petrol pump, not the colour.
- Many motors state the fuel type inside the filler flap or on the cap, so check it on the first fill in any car you do not know.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key if a household has one of each. So mark it.
- Before the nozzle leaves the pump the first time you fill a hired or new car, say "diesel" aloud. Silly, perhaps, but it does the trick.
- Put the phone away. This is an easy mistake to make whilst you are thinking about something else.
- Some diesels have a filler designed to refuse a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Stop as soon as you notice. Less petrol in your tank means a thinner mix. It does not change what to do next, which is still not to start the car.
Already put petrol in a diesel around Woodlands?
The order of things is brief, then. Never crank it, and do not switch the ignition on. Ask the attendants to help you roll it clear of the petrol pump if you're still at the forecourt, whether that's Shell or somewhere else. What went in, about how much, and if it's run: tell us those when you ring 0333 366 0103.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a different issue — Woodlands has a page all for it.
What makes one Woodlands petrol in a diesel task cost more than the next
Four separate jobs lie behind the four scenarios above — which is why there's no fair single quote. What moves the cost is mostly which of them you're in. Two things follow that: the petrol that got in as a proportion of what your tank holds, then the spot your car is in and whether our van can reach it safely.
That's why we ask three questions before pricing rather than after: what was put in, how much, and if it's run. Their replies are what change a range into one firm number.
About Woodlands and its setting
Woodlands is a suburban area situated on the riverside in Hampshire, with an elevation of 83 metres and a population of around 1500 residents. Woodlands is located near the city of Winchester, approximately 6 miles away, and is also close to nearby places such as New Alresford, Ovington, and Itchen Stoke. Woodlands has a mix of housing types, but semi-detached homes are the most predominant. Woodlands is about 53.9 miles from London, making it a commuter-friendly location.
Woodlands and Hampshire: where our fuel drain cover runs
Petrol in diesel calls in Woodlands — part of the SO postcode area — go to teams that likewise cover the locations around it, New Alresford, Ovington and Itchen Stoke among them. No need to move your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots we drain.
Still at the petrol pump around Woodlands?
Nothing beats it: that is where you now are. Switched off it stays; then phone.