How Worried Should You Be? Petrol in a Diesel Car in Chawley
Unstarted? Then less anxious than you likely feel. Until your ignition primes the pump, the starter cranks, or your car is driven, petrol in a diesel tank simply waits there and does nothing. Which means the truthful reply to the first Chawley question — "have I wrecked it?" — usually no. Keep it that way: leave your motor off and call Petrol in Diesel. Below, this page sets out what petrol actually does inside a diesel, how far it may have gone, and how to stop it happening to you again.
Inside the motor: what petrol in a diesel does
Two jobs fall to diesel on its route through a motor. It ignites, and before it burns it lubricates. The high-pressure fuel pump and the injectors are built to extremely fine gaps, and the diesel passing through them is what keeps those surfaces from grinding against one another.
Petrol does the first job badly and the second not at all. A pump running on a petrol mix is wearing itself out, since petrol is thinner than diesel and takes away the protection the fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that's where the rattling comes.
Together, those leave the shape of the problem plain. Not contact but circulation is what does the harm. Where the petrol is only in that tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds goes on, carried by the fuel, into your injectors further along, which is why a pump that has worked on that petrol is where a mechanical issue starts.
How bad is petrol in a diesel? Four scenarios our engineers see in Chawley
Filled up, and not started: no case is better. On a forecourt, and genuinely only there, the petrol is still confined to the tank — since anywhere else your car was driven to reach it. The task is emptying and flushing on the spot.
The ignition turned on, or a short start. Petrol has come out of that tank and got to the fuel filter and your lines, since the fuel system has been bled. Still generally easy: drain, flush, and your filter seen to.
Your pump has worked a few miles on weakened fuel — that's what driving the car does. Mileage is only half of it; how hard it was driven matters equally. Either way this work runs to that tank, the fuel lines, the fuel filter and clean fuel through the whole system. The school run to Cumnor Church of England School (Voluntary Controlled) is one thing. Getting as far as Oxford, under 3 miles away, makes a very different task — as does any distance on the Wheatley Spur, under 10 miles from Chawley, with the engine labouring hard all the way.
Driven until it protested. Clattering, an uneven idle, smoke, a throttle that has gone soft. That is the engine telling you its fuel has stopped acting like diesel. Leave it where it has stopped: a lay-by, a quiet street, the verge on Chawley Lane. The fuel drain and flush-through still go first, and they take care of it: if a vehicle is stopped soon, permanent damage is very rare.
Chawley drivers and that petrol in a diesel stories they hear
False: topping up to full with diesel makes it fine. It doesn't. Nothing comes out when you top up — the tank just holds more of the same mixture. Percentage isn't how a diesel fuel system copes with petrol, however much that advice supposes.
Myth: a current diesel copes with a bit of petrol. If anything, the opposite. Smaller components and higher pressure are the way a newer diesel runs its fuel, and that makes the lubrication count more, not less.
"It starts, it drives, so no harm done" — the myth that trips up more motorists than any other. Any petrol engine fed diesel normally will not run, and so the motorist stops and the damage stops with them. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, whilst the pump grinds. Running isn't the same as fine.
Not so: a two-stroke additive lets you to drive home. It is an old workaround, supposed for another problem. It does not put back what petrol has weakened, and that petrol is still in the tank later.
"Drain it yourself and you're sorted" — a myth, because after it has been running some petrol sits in the fuel filter and lines, ready to go straight back through the pump on your next start. Also, a can of petrol filled by the roadside is truly risky.
Why petrol in a diesel takes place at all
No one does it on purpose, and it is rarely carelessness. One way only, because of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally will not fit a petrol vehicle. That's how the forecourt makes it simple.
Routine and the vehicle falling out of step is when it takes place. Courtesy car, hire car, or a motor that's new. A household with one petrol and one diesel on the drive. Your ordinary forecourt, its pumps now in a different order. Rushing for a train outside Oxford and fuelling up en route. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you at the forecourt for its first tank — that's when. Add rain, a phone call or a back seat full of kids, and your hand does what it has always done.
Chawley motorists: how to avoid petrol in a diesel next time
- Check the pump, not the colour. In the UK unleaded handles are generally green and diesel black, but not on each forecourt. The label is what counts.
- The first fill in a new vehicle is the time to check your filler flap — inside it, or on the cap, many motors state which fuel to use.
- 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 label it.
- Before the nozzle leaves the pump the first time you fuel a hired or new motor, say "diesel" out loud. Daft, perhaps, yet it works.
- Put the phone away. This is an easy mistake to make whilst you're thinking about something else.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to block a petrol nozzle, and add-on devices are available for cars without one. They are a backstop, not a reason to stop reading the pump.
- Noticing it halfway? Stop there and then. A thinner mixture results from less petrol in the tank, yet your next step remains the same: do not start the vehicle.
Already put petrol in a diesel in Chawley?
Then, there is just a short order of things. Leave it unstarted, with your ignition switched off too. Still on the forecourt, at the nearest petrol station or anywhere else? Ask the staff to help you roll the car clear of the petrol pump. What went in, roughly how much, and if it has run: tell us those when you phone 0333 366 0103.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a different issue — Chawley has a page just for it.
Chawley petrol in a diesel jobs: why one costs more than another
There is no honest single price for this, since the four scenarios above are four different jobs. What shifts your cost is chiefly which of them you are in. Two things come after that: the petrol that was put in as a share of what that tank takes, then the place the vehicle is in and whether a technician can get to it safely.
Ahead of any quote, not after, come three queries: your fuel that got in, the volume, and whether it has run. That's why. A range turns into a straight figure when those replies are in.
About Chawley, for a moment
Chawley is a small village in Oxfordshire, situated near the city of Oxford and close to Cumnor Hill. Chawley sits at an elevation of 127 metres, with detached housing being the predominant type of accommodation. Chawley is located approximately 2.8 miles from Oxford, making it a commuter-friendly location. Chawley has a population of around 843 residents, with nearby places including Cumnor and Dean Court.
Fuel drain cover across Oxfordshire, Chawley included
Petrol in diesel call-outs in Chawley — part of the OX postcode area — go to teams that also cover the spots about it, Cumnor Hill, Cumnor and Dean Court included. 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 pump around Chawley?
Then, you could not be in a better position. Keep the vehicle switched off, and ring.