Should You Worry? Petrol in a Diesel Car in Common Side
Probably less than you are now — as long as nobody has started the vehicle. "Have I wrecked it?" is the first question everyone around Common Side asks, and the truthful answer is normally no, because petrol left in a diesel tank hurts nothing till it's dragged through the fuel system — by ignition priming, by the starter, or by driving. Petrol in Diesel is who to call, with the motor kept off, so it remains that way. Read on for three things: the effect petrol has inside a diesel motor, the signs of how far it has got, and the way to make sure you don't do it again.
Your engine and petrol in a diesel: what happens
On its way through a motor, diesel does two jobs. It combusts, and before it combusts it lubricates. What keeps the surfaces inside the high-pressure pump and the injectors from wearing against each other is the diesel flowing through them — they are made to very fine tolerances.
Poorly at the first, not at all at the second: that is petrol. It's thinner than diesel and removes the lubrication the fuel 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 opposite of what a diesel needs from its fuel. That is where the clattering comes from.
Taken together, they make clear what shape the problem has. Contact does not do the damage — movement does. Where that petrol is only inside your tank, it's a fault of fuel, nothing more. After your pump has been working on that petrol, a mechanical issue has started: anything shed by a pump that is wearing is carried onward to the injectors with the fuel.
Four situations our technicians see in Common Side: how bad is petrol in a diesel?
The best case there is: filled up, never started. At a forecourt, and truly only there, that petrol is still limited to your tank — since anywhere else the car was driven to reach it. The job is draining and purging on the spot.
Started for a second, or just the ignition on. The fuel system has been bled, and so petrol has left your tank and got to the fuel filter and your lines. Drain, flush, deal with your filter: still usually simple.
Those few miles on the road meant the pump running on fuel thinned by petrol the whole way. The work is that tank, the fuel lines, the fuel filter and clean fuel through the whole system, and how hard the vehicle was driven matters as much as how far. Short trips, such as the school run to Barlow CofE Primary School, are one matter. Very different once more: a run to Sheffield, under 10 miles away, or any mileage on the M1, under 10 miles from Common Side, where the motor kept running hard.
Knocking, an uneven idle, smoke, a throttle gone soft: driven till it complained. The fuel is not behaving like diesel any more, and your motor is telling you. Whether it's the verge on Valley Rise, a lay-by or a side road, stop where you are then leave it. The fuel drain and flush-through still come first, and they take care of it: when a car is stopped early, long-term damage is very unusual.
Stories Common Side motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It does not. A fuller tank of the same mixture is all it gives, since topping up takes out nothing. A diesel fuel system doesn't tolerate petrol by percentage in the way that advice assumes.
"Current diesels can handle a little petrol" — a myth, and nearer the opposite. Finer components and higher pressure are how a current diesel runs its fuel, and that makes the protection matter more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there's no harm done." A petrol engine fed diesel usually won't run, and so the driver stops and the harm stops with them. A diesel fed petrol generally starts, idles and drives away as if nothing has happened, whilst your pump wears. Fine and running are not the same at all.
Myth: a two-stroke additive lets you to drive home. It is an old fix, supposed for another problem. The petrol is still inside your tank after that, and whatever it has diluted isn't put back.
The next start draws petrol back round your pump from the fuel lines and the filter, where some of it ends up after the engine has been run. That's why draining the tank yourself does not sort it — a myth. It is also really hazardous to drain petrol into a can by the kerbside.
How it happens: petrol in a diesel
On purpose? Never. Through carelessness? Rarely, if ever. One way only, because of the nozzles: the narrower petrol one slides inside a diesel filler with almost no resistance, while the diesel one mostly won't fit a petrol motor. That's how the forecourt makes it simple.
It happens when routine and the car stop matching. A car that's new to you — hired, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps laid out differently. A hurried fill on the way to Dronfield with a train to catch. Precisely the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. Add rain, a phone call or a back seat full of children, and your hand does what it has always done.
How to avoid petrol in a diesel on your next fill-up around Common Side
- The label is what matters, so check the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- In a motor you do not know, look inside the flap over your filler or at the cap before the first fill: many motors print the fuel there.
- Good intentions do less than a sticker or a fob in a bright colour on your diesel's key when a household has one of each. So mark it.
- Before the nozzle leaves the pump the first time you fill a hired or new vehicle, say "diesel" out loud. Silly, perhaps, yet it does the trick.
- While you're 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 designed to refuse a petrol nozzle, and aftermarket devices exist for the remainder. Treat it as a safety net, then keep checking the pump.
- Less petrol means a thinner blend, and so stop as soon as you notice — though remembering that your next stage is unchanged. It's still not to fire it up.
Put petrol in a diesel in Common Side already?
The order of things is brief, then. Do not start the car, and do not switch your ignition on. If you're still at the forecourt — JET or anywhere else — ask the staff to help you push it away from the pump. Next, 0333 366 0103. We will ask what was put in, about how much, and if it has been run.
Corrosion and deposits form the issue with AdBlue, whereas petrol means lost lubrication. So if it was AdBlue, say so — and read its own Common Side page.
Common Side petrol in a diesel jobs: why one costs more than another
A fair single quote doesn't exist here: four scenarios, four separate tasks. Which of them you are in is chiefly what moves your cost. Next it's the share — how much petrol went in against how much your tank holds — and after that where your car is and whether our van can reach it safely.
What was put in, how much, and if it's run — three queries our technicians ask before costing, not after, for exactly that reason. A range turns into a straight figure when those replies are in.
About Common Side itself
Common Side is a village in Derbyshire, situated on the riverside at an elevation of 126 metres, with detached housing being the predominant type of accommodation. Common Side lies approximately 7.6 miles from Sheffield and 135 miles from London, making it a relatively accessible rural community. Common Side is surrounded by nearby places such as Crowhole, Newgate, and Peakley Hill, which are all part of the local landscape. Common Side has a population of around 646 residents, who live in a variety of detached homes.
Common Side and Derbyshire: where our fuel drain cover reaches
Common Side sits in the S postcode area, and our teams that answer petrol in diesel call-outs there work the locations around it as well — Crowhole, Newgate and Peakley Hill among them. No need to bring your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
In Common Side and still at the petrol pump?
Nothing beats it: that's where you are. Keep it off. Phone.