Townend: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — as long as nobody has started the vehicle. Petrol sitting in a diesel tank does nothing to your motor until something draws it through the system — the ignition priming the pump, the starter, or driving on its own. So the fair answer to the first question everyone in Townend asks, "have I ruined it?", is normally no. Petrol in Diesel is who to phone, with the engine left off, and so it remains that way. What petrol actually does to a diesel, how to gauge how far it's travelled, and how to keep it from happening a second time: that is the rest of this page.
Inside the motor: what petrol in a diesel does
Two jobs fall to diesel on its route round a motor. Before it combusts, it protects — then it ignites. Your high-pressure pump and your injectors are made to extremely fine tolerances, and your diesel passing through them is what keeps those surfaces from wearing against each other.
Of those two jobs, petrol manages the first badly and the second not at all. The clattering comes from petrol being designed not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips away the protection your system rests on, and any pump running on such a mix is wearing itself.
Put these together and the shape of the trouble is clear. It is movement that does the damage, not contact. Where the petrol is only inside that tank, it is a problem of fuel, nothing more. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the injectors downstream.
Townend, petrol in a diesel: four cases, from mild to major
Filled but never started — the best it gets. That petrol is inside the tank and just the tank, and the job is a drain and a flush where your car sits. This is the one situation that can only truly occur at a forecourt, because anywhere else your car has been driven to get there.
Started for a moment, or just the ignition on. Petrol has left the tank and reached your filter and the fuel lines, because the system has been bled. Usually little more than clearing, cleaning and sorting the filter, so still straightforward.
Those few miles on the road were the pump working on fuel thinned by petrol the whole way. Tank, lines, filter, then fresh fuel run through the whole circuit: that is the work, and the way your car was driven counts as much as the mileage. On the school run to the local primary school, the mileage is small. A run as far as Glasgow, under 15 miles away, is a very different task. So is any mileage on the M8, under 3 miles from Townend, where the motor has been running hard the whole time.
Clattering, an uneven idle, smoke, a throttle gone soft: driven until it complained. The motor is telling you your fuel is no longer behaving like diesel. Stop wherever you are — the verge on Chapelton Gardens, a lay-by, a side street — and leave the vehicle there. A car pulled over early very seldom has long-term damage, since the fuel drain and the flush-through, which still go first, sort it out.
Townend people and that petrol in a diesel myths they hear
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Nothing comes out when you top up — the tank just carries more of the same mixture. Percentage is not how a diesel fuel system tolerates petrol, whatever that guidance presumes.
Not so: a newer diesel copes with a bit of petrol. Rather, the opposite. Smaller parts and higher pressure are how a current diesel runs its fuel, and that makes the lubrication matter more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that catches people. The motorist of a petrol engine fed diesel usually has no choice but to stop, since it will not run, and the damage stops with them. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, while the pump wears. Fine and running aren't the same at all.
An old workaround for a separate problem lies behind this one. Myth: "Add some two-stroke oil and drive the car home." What petrol has thinned stays thinned, and the petrol remains inside that tank regardless.
"Drain it yourself and you are sorted" — a myth, since after it has been running some petrol sits in your filter and lines, ready to go right back through your pump at your next start. Emptying petrol into a can at the roadside is also genuinely dangerous.
Petrol in a diesel: how does it happen?
Nobody does it on purpose, and it is seldom carelessness. The forecourt makes it easy: the petrol nozzle is the slimmer of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle generally won't go into a petrol car at all. So the mistake runs one way.
The moment routine stops matching the car is the moment it occurs. A vehicle that is new to you — a hire car, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. Your ordinary forecourt, its pumps suddenly in a different order. A hurried fill en route to Dumbarton Central with a train to catch. The first fill-up in a diesel Volkswagen Golf after years of driving petrol is precisely the moment it takes place. Throw in a back seat full of kids, a phone call or rain, and habit wins.
Townend drivers: how to avoid petrol in a diesel next time
- The label is what counts, and so check the petrol pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on each 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 motors print the fuel type there.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of meaning to remember, in a home with one of each.
- It seems daft and it works: on the first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away and keep your mind on the pump.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to block a petrol nozzle, and add-on devices exist for cars without one. They are a safety net, not a reason to stop checking the petrol pump.
- Stop as soon as you realise. Less petrol in your tank makes a thinner mix. It doesn't change what to do next, which is still not to start the car.
Petrol already in a diesel in Townend? Begin here
Then, there's just a short order of things. Leave it unstarted, with the ignition off too. Still on the forecourt, at Murco or anywhere else? Ask the staff to help you push the car away from the pump. What was put in, roughly how much, and if it's run: tell us those when you ring 0333 366 0103.
Corrosion and deposits are the issue with AdBlue, whereas petrol means lost protection. So if it was AdBlue, say so — and see its own Townend page.
One petrol in a diesel job around Townend costs more than another. Why?
A fair single price does not exist here: four scenarios, four separate jobs. Mostly, the cost moves with which situation you are in. After that it's the share — how much petrol went in against how much the tank takes — and then where the vehicle is and whether a technician can get to it safely.
That's why we ask three queries before pricing rather than after: what got in, how much, and if it's run. A range becomes a straight figure when those replies are in.
About Townend, for a moment
Townend is a coastal suburban area in West Dunbartonshire, situated near the towns of Dumbarton and Bellsmyre. Townend lies at a low elevation of around 9 metres, close to the shores of the Clyde Estuary. Townend is characterized by its predominantly flat-type housing, which reflects the typical residential architecture of the region. Townend is located near the larger town of Dumbarton and the suburban area of Silverton, and is within commuting distance of Glasgow.
Townend and West Dunbartonshire: where our fuel drain cover runs
Our teams answering petrol in diesel call-outs around Townend, in the G postcode area, equally work the places around it, Bellsmyre, Dumbarton and Silverton among them. No need to bring the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
In Townend and still at the pump?
Then you're in the best spot there is. Switched off it remains; then phone.