Should You Worry? Petrol in a Diesel Car in Franche
If it hasn't been started, worry far less than you likely are. Until your ignition primes the pump, the starter turns, or the car is driven, petrol in a diesel tank simply waits there and does nothing. Which means the honest reply to the first Franche question — "have I ruined it?" — usually no. Leave your engine off and call Petrol in Diesel — that is how you keep it that way. The rest of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
What petrol in a diesel does to your engine
Diesel does two jobs on its way through a motor. It ignites, and before it combusts it lubricates. What keeps the surfaces inside the high-pressure pump and your injectors from wearing against one another is the diesel flowing through them — they are made to very fine clearances.
Of those two jobs, petrol manages the first poorly and the second never. It is runnier than diesel and removes the lubrication the system hinges on, and so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the knocking comes from.
Put those together and the shape of the issue is plain. The harm is done by movement, not by contact. Where the petrol is only in your tank, it is a fault of fuel, nothing more. After your pump has been running on that petrol, a mechanical problem has begun: anything shed by a pump that's wearing down is carried onward to your injectors with the fuel.
Franche, petrol in a diesel: four situations, from mild to major
Filled but not once started — the best it gets. Only the tank has petrol in it, so the task is draining the tank and purging the system where the car stands. This situation can only truly take place at a forecourt: anywhere else, the car got there by being driven.
A moment's running, or just your ignition on. With the system primed, the lines and filter now hold petrol that came from the tank. Usually nothing more than clearing, purging and sorting the filter, and so still easy.
Driven a couple of miles. Now the pump has spent these miles working on weakened fuel. Tank, lines, filter, then fresh fuel run through the entire circuit: that is the work, and the way your car was driven matters as much as the distance. Short trips, like the school run to Franche Primary School, are one matter. Very different once more: a trip to Wolverhampton, under 15 miles away, or any mileage on the M5, under 10 miles from Franche, where your engine kept running hard.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The fuel is not acting like diesel any more, and your engine is telling you. Whether it's the verge on Tynings Close, a lay-by or a side street, stop there and leave it. Permanent damage is very uncommon if a vehicle is stopped quickly, and the fuel drain and flush-through that still go first sort it out.
Myths Franche motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It doesn't. A fuller tank of the same mixture is all it gives, since topping up takes out nothing. Percentage isn't how a diesel fuel system tolerates petrol, however much that advice supposes.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the reverse. At higher pressure, through finer components: that is how a current diesel handles its fuel, and so the protection counts more, not less.
This is the one that fools drivers. Myth: "If it starts and drives, there's no damage done." Any petrol engine fed diesel normally will not run, so the motorist stops and the damage stops with them. A diesel fed petrol usually starts, ticks over and drives away as if nothing has happened, while your pump wears. Running doesn't mean fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old fix, supposed for another issue. What petrol has diluted remains diluted, and the petrol stays inside that tank anyway.
"Drain it yourself and you are sorted" — a myth, because after it has been running some petrol sits in your filter and lines, ready to go straight back through your pump at the next start. Clearing petrol into a can by the kerbside is also truly risky.
How does petrol in a diesel occur?
It is rarely carelessness, and no one does it on purpose. 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.
The moment routine stops matching the car is the moment it takes place. Courtesy car, hire car, or a motor that is new. A household with one petrol and one diesel on the driveway. The pumps in a different order on a familiar forecourt. Fuelling up in a hurry en route to Kidderminster, with a train to catch. Exactly the moment it occurs: after years of driving petrol, a driver fills a diesel Nissan Qashqai for the first time. Throw in a back seat full of kids, a phone call or rain, and habit takes over.
Avoiding petrol in a diesel next time you fill up around Franche
- Check the pump, not the colour. In the UK unleaded handles are normally green and diesel black, yet not on every forecourt. The label is what matters.
- Plenty of cars state the fuel type inside your filler flap or on the cap, and so check there on the first fill in a car you do not know.
- A coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember, in a household with one of each.
- It seems silly and it does the trick: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump.
- Put the phone away. This is an easy mistake to make while you're thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to refuse a petrol nozzle, and aftermarket devices are available for the rest. Count it as a backstop, then keep reading the petrol pump.
- Stop the moment you realise. Less petrol in that tank means a weaker blend. It doesn't change what to do next, which is still not to crank it.
Already put petrol in a diesel around Franche?
Short and simple, then, is the order of things. Do not switch the ignition on, and don't fire it up. The staff on the forecourt — whether at Esso itself or wherever you filled up — will normally help roll it away from the petrol pump if you ask. Ring 0333 366 0103 next, with three answers — the fuel, the approximate quantity, and whether it has run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate issue — Franche has a page all for it.
What makes one Franche petrol in a diesel task cost more than the next
Four different tasks lie behind the four situations above — which is why there's no fair single price. Mostly, your cost shifts with which one you are in. Two things come after that: the petrol that got in as a share of what the tank holds, then the place the vehicle is in and whether our van can get to it safely.
Three questions come first, before any quote, instead of after — what was put in, how much, has it run — and this is the reason. Their answers are what change a range into one firm number.
About Franche
Franche is a suburban area in Worcestershire, situated on the riverside at an elevation of 61 metres. Franche lies near several smaller communities, including Low Habberley, Habberley, and Wolverley, and is located approximately 14 miles from Wolverhampton. Franche is characterized by its predominantly semi-detached housing stock, reflecting the typical residential development patterns of the West Midlands region. Franche is also within commuting distance of larger cities, being around 110 miles from London.
Fuel drain cover across Worcestershire, Franche included
Petrol in diesel calls around Franche — part of the DY postcode area — go to teams that also cover the spots about it, Low Habberley, Habberley and Wolverley included. You need not bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places where we work.
Still at the petrol pump in Franche?
The best place there is, then — that is where you are. Turned off it stays; then phone.