Upper Weston: Petrol in a Diesel Car? How Worried to Be
Not started? Then less anxious than you likely feel. Petrol sitting in a diesel tank does nothing to the engine until something draws it through the fuel system — the ignition priming the pump, the starter, or driving on its own. So the fair answer to the first query anyone around Upper Weston asks, "have I wrecked it?", is normally no. To leave the vehicle that way, phone Petrol in Diesel and leave your motor switched off. 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 again.
Inside the engine: what petrol in a diesel does
Two tasks fall to diesel on its journey through a motor. Oiling comes before burning; it does both. Your high-pressure pump and the fuel injectors are made to extremely fine gaps, and your diesel passing through them is what stops those surfaces from wearing down against one another.
Of those two jobs, petrol handles the first badly and the second not at all. It's thinner than diesel and strips away the lubrication the fuel system hinges on, and so a pump running on a petrol mix 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 clattering comes from.
Put those together and the shape of the trouble is plain. The damage is done by circulation, not by contact. Where the petrol is only in that tank, it's a problem of fuel, nothing more. After the pump has been running on that petrol, a mechanical problem has started: anything shed by a pump that is wearing is carried onward to your injectors with the fuel.
How serious is petrol in a diesel? Four scenarios our technicians see around Upper Weston
Fuelled but not once started — as good as it gets. On a forecourt, and genuinely only there, that petrol is still confined to your tank — because everywhere else the vehicle was driven to get to it. The task is emptying and flushing on the spot.
Started for a moment, or just the ignition on. With the system primed, your lines and filter now contain petrol that has come from that tank. Still normally easy: drain, flush, and the filter sorted.
Driven a few miles. Now your pump has spent these miles working on diluted fuel. Tank, lines, filter, then clean fuel put through the whole system: that is this work, and the way the car was driven counts as much as the distance. On the school run to Weston All Saints CofE Primary School, the distance is short. Very different once more: a trip to Bath, under 3 miles away, or some miles on the M4, under 10 miles from Upper Weston, where the motor kept running hard.
Knocking, a ragged idle, smoke, a throttle gone soft: driven till it complained. The fuel is not behaving like diesel any more, and your engine is saying so. Whether it's the verge on Greenacres, a lay-by or a side street, stop where you are and leave it. The fuel drain and flush-through still come first, and they deal with it: if a vehicle is pulled over quickly, long-term damage is very unusual.
Stories Upper Weston motorists hear about petrol in a diesel
False: topping up to full with diesel makes it fine. It does not. Nothing comes out when you top up — the tank just carries more of the same blend. That guidance presumes a diesel fuel system tolerates petrol by percentage. It doesn't.
Not so: a current diesel copes with a bit of petrol. If anything, the reverse. Finer parts and higher pressure are how a newer diesel runs its fuel, and that makes the protection matter more, not less.
This is the one that fools people. Myth: "If it starts and drives, there's no damage done." Diesel in a petrol motor usually leaves a motor that won't run: the motorist stops, and so does the harm. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile the pump wears. Fine and running aren't the same at all.
An old workaround for a different problem is behind this one. Myth: "Add some two-stroke oil and drive the car home." None of what petrol weakened gets put back by it — and afterwards, the tank still holds that petrol.
If the motor has been run, part of that petrol sits in the fuel filter and the lines, not your tank — and your next start pulls it straight back through your pump. So the myth "drain that tank yourself and you're sorted" doesn't stand up. On top of that, petrol cleared into a can by the road is truly hazardous.
Petrol in a diesel: how does it occur?
Carelessness is seldom the cause, and no one means to do it. A diesel nozzle mostly will not fit a petrol motor, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error simple, and just in that direction.
It happens when habit and your car stop matching. Any vehicle that's new to you — hired, on loan as a courtesy car, or brand new. Two vehicles on one driveway, one petrol, one diesel. Your normal forecourt, its pumps now in a different order. A rushed fill en route to Oldfield Park with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is precisely the moment it happens. The hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
Next time you fill up in Upper Weston: preventing petrol in a diesel
- Read 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 matters.
- Many vehicles state the fuel inside your filler flap or on the cap, and so check it on your first fill in a motor you don't know.
- One of each in the house? Mark your key to your diesel — a coloured fob, a sticker — since meaning to remember isn't enough.
- Before the nozzle leaves the pump the first time you fill a hired or new car, say "diesel" aloud. Daft, yes, yet it does the trick.
- Mistakes like this are easy to make whilst your mind is on something else, and so the phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to refuse a petrol nozzle, and add-on devices are available for cars without one. They are a safety net, not a reason to stop reading the pump.
- Stop as soon as you realise. Less petrol in your tank means a thinner mix. It doesn't change what to do next, which is still not to crank it.
Petrol already in a diesel in Upper Weston? Begin here
Short and simple, then, is the order of things. Starting it is out, and so is switching on your ignition. The attendants on the forecourt — whether at Gulf itself or wherever you filled up — will normally help roll it away from the pump if you ask. Then phone 0333 366 0103 and tell us what was put in, about how much, and if it's run.
If it was AdBlue rather than petrol, say so. That's a separate problem — corrosion and deposits rather than lost lubrication — and it has its own page for Upper Weston.
What makes one Upper Weston petrol in a diesel job cost more than the next
A fair single price does not exist here: four situations, four separate tasks. Mostly, the cost moves with which one you're in. Where the car is matters too, and whether a technician can safely reach it, after the ratio of petrol to what your tank holds.
Three queries come first, before any quote, instead of after — what was put in, how much, has it run — and that is the reason. A range becomes a straight figure once the replies are in.
About Upper Weston, for a moment
Upper Weston is a suburban area located on the riverside in Somerset, with a mix of semi-detached housing and other residential properties. Upper Weston sits near the city of Bath, approximately 2.1 miles away, and is part of the larger urban area surrounding the city. Upper Weston has a population of around 2995 people and is situated at an elevation of 96 metres, close to nearby places such as Weston and Combe Park.
Upper Weston and Somerset: where our fuel drain cover runs
Our teams answering petrol in diesel call-outs in Upper Weston, in the BA postcode area, equally work the places near it, Weston, Combe Park and Lansdown included. You need not bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
Upper Weston: still at the pump?
Nothing beats it: that is where you now are. Keep it off. Call.