Otterton: Petrol in a Diesel Car? How Worried to Be
Far less than you likely are, provided it hasn't been started. Till your ignition primes the pump, the starter turns, or the car is driven, petrol in a diesel tank simply sits there and does no harm. Which means the truthful reply to the first Otterton question — "have I ruined it?" — normally no. Keep it that way: leave your motor off and phone Petrol in Diesel. The rest of this page covers what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you a second time.
What petrol in a diesel does to the engine
Two jobs fall to diesel on its route through a motor. It protects to begin with, and after that does it burn. What stops the surfaces inside your high-pressure pump and the injectors from wearing against one another 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 poorly. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, leaving a pump running on that mixture wearing itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is where you hear the clattering.
Put those together and the shape of the problem is plain. Not contact but movement is what causes the damage. Any tank with petrol in it is a fuel fault. The beginning of a mechanical problem is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with the fuel to the fuel injectors downstream.
Four scenarios we see in Otterton: how serious is petrol in a diesel?
Fuelled, and never started: no case is better. The petrol is in that tank and just your tank, and the task is a drain and a flush where the vehicle stands. This is the one scenario that can only really occur on a forecourt, since anywhere else your car has been driven to get there.
A brief spell of running, or merely your ignition on. With the fuel system primed, your lines and filter now contain petrol that came from your tank. Still generally easy: drain, flush, and the fuel filter sorted.
Some miles driven, and the pump has spent each of them labouring on thinned fuel. Tank, lines, filter, then fresh fuel put through the whole circuit: that's this work, and the way the car was driven matters as much as the miles. The school run to Otterton Church of England Primary School is one thing. Very different once more: a run to Exeter, under 15 miles away, or some mileage on the M5, under 10 miles from Otterton, where the engine never stopped working hard.
Driven until it complained. Rattling, a ragged idle, smoke, a throttle that has gone soft. The fuel isn't behaving like diesel any more, and the motor is telling you. Leave it wherever it has stopped: a lay-by, a quiet street, the verge on Lea Road. The fuel drain and flush still come first, and they deal with it: when a vehicle is pulled over early, lasting damage is very rare.
Stories Otterton motorists 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 by topping up — you are left with a fuller tank, still the same mixture. The idea behind that guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A current diesel can cope with a bit of petrol." If anything, the opposite. A current diesel sends its fuel through more precise parts at higher pressure, which makes the protection count more, not less.
One myth that catches motorists out: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel usually has no choice but to stop, since it will not run, and the damage stops there. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile your pump grinds. Running isn't the same as fine.
An outdated fix for a different issue lies behind this one. Myth: "Add some two-stroke oil and drive it home." None of what petrol weakened is put back by it — and afterwards, your tank still contains the petrol.
If the engine has run, part of that petrol is in the filter and the fuel lines, not the tank — and your next start sends it straight back through the pump. So the myth "drain your tank yourself and you're sorted" doesn't stand up. Also, a can of petrol drained by the roadside is truly risky.
How does petrol in a diesel occur?
No one does it on purpose, and it is rarely carelessness. A diesel nozzle generally will not go into a petrol motor, yet the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake easy, and just in one direction.
Routine and your car getting out of step is how it occurs. A motor that's new to you — hired, on loan as a courtesy car, or brand new. Two motors on one driveway, one petrol, one diesel. The pumps in a different order on a well-known forecourt. Racing for a train outside Exmouth and fuelling up en route. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is exactly the moment it occurs. 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 in Otterton: avoiding petrol in a diesel
- A green handle for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Trust the label on the pump, not the colour.
- Inspect the filler flap. Plenty of motors state the fuel inside the flap or on the cap. Look at it on the first fill in any car you don't know.
- One of each in the home? Label your key to the diesel — a coloured fob, a sticker — because intending to remember is not enough.
- It seems daft and it works: on your first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- While you are thinking about something else, this is an easy mistake to make — so put your phone away.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to block a petrol nozzle, and aftermarket devices are available for the rest. Count it as a safety net, and keep reading the petrol pump.
- Stop as soon as you realise. Less petrol inside the tank means a thinner mixture. It doesn't change what to do next, which is still not to start the car.
Already put petrol in a diesel in Otterton?
The order of things is short, then. Never crank it, and do not turn the ignition on. Ask the staff to help you roll it clear of the petrol pump if you're still at the forecourt, whether that is East Budleigh Garage or somewhere else. Call 0333 366 0103 next, with three facts — the fuel, the approximate volume, and whether it has run.
Say so if it was AdBlue instead of petrol: it's a separate issue, with its own page for Otterton, since AdBlue brings corrosion and deposits instead of lost lubrication.
What makes one Otterton petrol in a diesel job cost more than the next
There's no fair single price for this, because the four situations above are four separate tasks. Which of them you are in is mostly what shifts your cost. Where the vehicle is counts too, and whether a technician can safely reach it, after the share of petrol to what your tank takes.
Three questions come first, before quoting, rather than after — what got in, how much, has it run — and this is the reason. A range turns into a straight figure when those answers are in.
About Otterton
Otterton is a small coastal village in Devon, situated near the mouth of the Otter estuary and close to the nearby settlements of North Star, East Budleigh, and Colaton Raleigh. Otterton sits at a low elevation of around 15 metres, looking out over the coastal landscape. Otterton has a population of approximately 673 residents, living in predominantly detached housing. Otterton is located near the city of Exeter, which is about 11 miles away.
Fuel drain cover around Otterton and across Devon
Otterton sits in the EX postcode area, and the vans that answer petrol in diesel calls there work the places near it as well — North Star, East Budleigh and Colaton Raleigh among them. The car does not need to come to us: our engineers drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Still at the petrol pump around Otterton?
No position is better: that is where you are. Keep it off. Phone.