Should You Worry? Petrol in a Diesel Car in Garnethill
Not started? Then less anxious than you likely are. "Have I ruined it?" is the first thing everyone in Garnethill asks, and the honest answer is usually no, because petrol resting in a diesel tank harms nothing till it is drawn through the fuel system — by ignition priming, by your starter, or by being driven. To leave the vehicle that way, ring Petrol in Diesel and leave your motor alone. Further down, 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 a second time.
Inside the engine: what petrol in a diesel really does
Two jobs fall to diesel on its route round a motor. Before it ignites, it lubricates — then it combusts. Very fine clearances go into the injectors and your high-pressure pump, and only your diesel flowing through stops those surfaces grinding together.
Of those two tasks, petrol handles the first badly and the second not at all. The clattering comes from petrol being designed not to ignite when compressed, which is exactly the opposite of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication the system rests on, and any pump running on that mix is wearing itself.
The shape of the problem is plain once you put those together. Not contact but circulation is what does the damage. Petrol in the tank is a fuel fault. The beginning of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with the fuel to the injectors downstream.
Garnethill, petrol in a diesel: four cases, from mild to significant
Filled up, and never started: nothing beats it. The petrol is in your tank and just your tank, and the task is a drain and a flush where your car sits. This is the one situation that can only truly take place on a forecourt, as anywhere else your car has been driven to get there.
Your ignition turned on, or a short start. With the fuel system primed, the lines and filter now hold petrol that came from the tank. Drain, flush, see to the fuel filter: still normally straightforward.
Those few miles on the road were the pump labouring on fuel weakened by petrol throughout. Tank, lines, filter, then clean fuel put through the entire system: that is the work, and the way your car was driven matters as much as the miles. Driving the children to the local primary school is one kind of trip. Any distance on the M8, under a mile from Garnethill, means your engine has worked hard throughout, and a run to Glasgow, under 3 miles away, makes a very different task as well.
Driven until it complained. Knocking, a lumpy idle, smoke, a throttle that has gone soft. That's the engine telling you its fuel no longer is behaving like diesel. Pull up where you are — on the verge on Rose Street, at the kerb, down a side road — and don't move it again. Long-term damage is very uncommon when a car is stopped soon, and the fuel drain and flush-through that still go first sort it out.
Petrol in a diesel stories Garnethill motorists hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it'll be." A bigger tank of the same mixture is all it gives, because topping up removes nothing. The assumption behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. Finer parts and higher pressure are the way a newer diesel runs its fuel, and that makes the protection matter more, not less.
The myth that catches motorists out: if it starts and drives, it must be unharmed. Diesel in a petrol motor generally leaves a motor that will not run: the driver stops, and so does the damage. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually will; meanwhile your pump grinds. Running isn't the same as fine.
Not so: a two-stroke additive makes it safe to drive home. It is an old workaround, meant for another issue. What petrol has weakened stays weakened, and that petrol remains in that tank regardless.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol sits in the fuel filter and lines, ready to go right back through the pump on your next start. Draining petrol into a can by the roadside is also genuinely dangerous.
Petrol in a diesel: how does it occur?
No one does it on purpose, and it's rarely carelessness. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol vehicle at all. The forecourt makes it easy, and the error runs one way.
The moment routine stops matching your car is the moment it occurs. Hire cars, courtesy cars, and cars that are new to you. One petrol and one diesel on the drive of the same household. A familiar forecourt with the pumps in a different order. A train to catch, and a hurried fill on the way to Charing Cross (Glasgow). A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: exactly when it happens. Your hand does what it has always done once you add rain, a phone call or a back seat full of kids.
Garnethill motorists: how to prevent petrol in a diesel next time
- The label is what counts, and so check the 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 don't know, look inside the flap over the filler or at the cap before your first fill: plenty of vehicles print the fuel type there.
- Label the key. In a household with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- It sounds daft and it does the trick: on the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the pump.
- Mistakes like this are easy to make while your mind is on something else, so your phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler built to reject a petrol nozzle, and add-on devices exist for motors without one. They are a backstop, not a reason to stop checking the pump.
- Spotting it mid-fill? Stop at once. A thinner mix follows from less petrol in that tank, yet your next stage remains the same: do not fire it up.
Put petrol in a diesel in Garnethill already?
Then, there is only a short order of things. Starting it is out, and so is turning on your ignition. The staff at the forecourt — whether at BP itself or wherever you filled up — will usually help roll it clear of the pump if you ask. Phone 0333 366 0103 next, with three facts — your fuel, the approximate volume, and whether it's run.
Say so if it was AdBlue instead of petrol: it is a different problem, with its own page for Garnethill, since AdBlue brings corrosion and deposits rather than lost protection.
Why one petrol in a diesel task around Garnethill costs more than another
The four scenarios above are four separate tasks, so no single quote for this would be honest. Which of them you're in is chiefly what moves the cost. After that it is the ratio — how much petrol got in against how much your tank takes — and then where your car is and whether a technician can get to it safely.
That's why we ask three queries before costing instead of after: what was put in, how much, and if it's run. A range becomes a straight figure when those replies are in.
About Garnethill
Garnethill is a suburban area in Glasgow City, situated near the River Kelvin and close to the city centre. Garnethill sits at an elevation of 46 metres, with many of its residents living in flats. Garnethill is adjacent to other Glasgow neighbourhoods, including Blythswood New Town, Cowcaddens, and Anderston, and is just a short distance from the city's main amenities.
Across Glasgow City and in Garnethill: fuel drain cover
The vans answering petrol in diesel calls around Garnethill, in the G postcode area, also work the spots around it, Blythswood New Town, Cowcaddens and Anderston among them. The vehicle doesn't need to come to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
At the petrol pump around Garnethill, still?
In that case, you couldn't be in a better place. Switched off it remains; then phone.