Should You Worry? Petrol in a Diesel Car in Chobham
Likely less than you already are — provided nobody has started the vehicle. Till your ignition primes the pump, the starter cranks, or your vehicle is driven, petrol in a diesel tank simply rests there and does no harm. Which means the honest reply to that first Chobham question — "have I wrecked it?" — usually no. Leave your motor off then ring Petrol in Diesel — that keeps it like that. Further down, you will find what petrol really does inside a diesel, how far it might have gone, and how to stop it happening to you a second time.
Inside the motor: what petrol in a diesel does
On its way through a motor, diesel does two jobs. It lubricates first, and only then does it burn. What stops the surfaces inside the high-pressure fuel pump and your injectors from wearing down against each other is your diesel flowing through them — they are built to extremely fine clearances.
The second job petrol doesn't do at all, and the first it does badly. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump on that mixture to wear itself. It is equally made to resist igniting under compression — the opposite of what a diesel needs — which is why you hear the clattering.
The shape of the issue is clear once you put those together. The harm is done by movement, not by contact. Any tank with petrol in it is a fuel problem. Whatever a worn pump sheds goes on, borne by your fuel, into the fuel injectors further along, which is why a pump that has worked on that petrol is where a mechanical problem begins.
Petrol in a diesel around Chobham: how serious is it? Four situations
Fuelled, and never started: nothing beats it. Being on a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With that petrol kept inside that tank alone, it is drained and purged on the spot, and nothing more is needed.
Ignition on, or started for a second. Once primed, the system has drawn petrol out of the tank as far as the fuel filter and your lines. That's generally still an easy task — a drain, a flush, and your filter seen to.
Those few miles on the road meant the pump running on fuel diluted by petrol the whole way. The work is your tank, the lines, your filter and fresh fuel through the whole circuit, and how hard your car was driven matters as much as how far. Short trips, such as the school run to St Lawrence CofE Primary School, are one thing. A run as far as Westminster, under 25 miles away, is a very different job. So is any distance on the M3, under 3 miles from Chobham, where your engine has been running hard the whole time.
Driven on until it protested — clattering, smoke, a lumpy idle, a soft throttle. The fuel isn't behaving like diesel any more, and your motor is telling you. Whether it is the verge on Bagshot Road, a lay-by or a side street, stop where you are and leave it. A car pulled over soon very rarely has long-term damage, since the fuel drain and the flush, which still come first, sort it out.
What Chobham motorists get told about petrol in a diesel — and the myths in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A fuller tank of the same mixture is all it gives, since topping up removes nothing. Percentage is not how a diesel fuel system tolerates petrol, whatever that guidance supposes.
"Modern diesels can handle a little petrol" — a myth, and nearer the opposite. A newer diesel sends its fuel through more precise parts at higher pressure, which makes the protection matter more, not less.
This is the one that catches people. Myth: "If it starts and drives, there's no harm done." Diesel in a petrol motor normally leaves a motor that will not run: the motorist stops, and so does the harm. Feed petrol to a diesel and it generally fires up, idles and pulls away like nothing has happened — all while its pump is wearing. Running does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct problem. What petrol has thinned stays diluted, and that petrol remains inside that tank anyway.
Myth: "Drain the tank yourself and you are sorted." Once your engine has been run, some of the petrol is no longer inside your tank: it is in your filter and your lines, and it goes right back through your pump at the next start. Also, a can of petrol drained at the kerbside is genuinely risky.
How does petrol in a diesel occur?
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle mostly will not go into a petrol motor, yet the narrower petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one error simple, and only in one direction.
The moment habit stops matching the vehicle is the moment it takes place. A new motor, a hire car or a courtesy car. Two vehicles on one driveway, one petrol, one diesel. A well-known forecourt with the pumps in a different order. Fuelling up in a hurry en route to Longcross, with a train to catch. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Renault Clio for the first time. Add rain, a phone call or a back seat full of kids, and your hand does what it has always done.
Chobham people: how to avoid petrol in a diesel next time
- The label is what counts, so read the petrol pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- Many motors state the fuel type inside the filler flap or on the cap, so check there on your first fill in any motor you don't know.
- Label your key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- "Diesel", aloud, before you pick up the nozzle — each time a new or hired car needs its first tank. It seems daft. It does the trick.
- Tuck the phone away. This is an easy mistake to make whilst you're thinking about something else.
- Some diesels have a filler built to reject a petrol nozzle, and devices you can add are available for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- As soon as you realise, stop: less petrol inside your tank makes a weaker blend. What to do next doesn't change, though — still do not start it.
Put petrol in a diesel around Chobham already?
The order of things is brief, then. Starting it is out, and so is turning on your ignition. Ask the attendants to help you roll it away from the petrol pump if you're still at the forecourt, whether that is Esso or somewhere else. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it's been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a different fault — Chobham has a page just for it.
One petrol in a diesel task in Chobham costs more than another. Why?
There is no fair single quote for this, since the four scenarios above are four separate tasks. The situation itself does most of the work of moving the cost. Two things follow that: the petrol that was put in as a proportion of what the tank takes, then the place the car is in and whether a technician can reach it safely.
Ahead of any quote, not after, we ask three queries: the fuel that was put in, the volume, and if it has run. That is why. Their answers are what turn a range into one firm number.
About Chobham itself
Chobham is a village in Surrey, situated on the banks of the River Bourne at an elevation of around 30 metres. Chobham lies approximately 23 miles southwest of central London, near the neighbouring communities of Burrowhill, Castle Green, and Penny Pot. Chobham has a population of around 890 residents, predominantly living in detached homes. Chobham is characterized by its riverside setting and surrounding countryside.
Fuel drain cover in Chobham and across Surrey
Chobham sits in the GU postcode area, and our teams that answer petrol in diesel calls there work the places near it as well — Burrowhill, Castle Green and Penny Pot among them. Our technicians drain wherever the car is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
At the petrol pump in Chobham, right now?
Then you are in the best position there can be. Leave it switched off, and ring.