Tuckton: Petrol in a Diesel Car? How Worried to Be
Not started? Then less anxious than you likely are. Petrol sitting in a diesel tank does nothing to the motor till something draws it through the system — your ignition priming your pump, your starter, or the drive on its own. So the truthful answer to the first query anyone in Tuckton asks, "have I ruined it?", is normally no. Petrol in Diesel is who to ring, with the engine kept off, so it remains that way. The remainder of this page explains what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you again.
Inside the motor: what petrol in a diesel does
Passing through an engine, diesel does two jobs at the same time. It protects first, and after that does it burn. Designed to extremely fine clearances, your injectors and the pump rely on your diesel flowing through them to stop their surfaces wearing against one another.
Of these two jobs, petrol manages the first badly and the second not at all. A pump working on a petrol mixture is wearing itself out, because petrol is runnier than diesel and strips out the protection the fuel system depends on. Petrol is also made to resist igniting under compression — the opposite of what a diesel wants from its fuel — and that's where any rattling starts.
Seen together, they make clear the shape the issue takes. It is movement that causes the damage, not contact. A tank with petrol in it is a fuel issue. Whatever a worn pump sheds goes on, borne by your fuel, into the injectors further along, which is why a pump that has been working on the petrol is where a mechanical problem starts.
Petrol in a diesel around Tuckton: how serious is it? Four situations
The best case there is: filled up, not once started. That petrol is in the tank and only your tank, and the task is a drain and a flush where the car sits. This is the one scenario that can only really take place on a forecourt, since anywhere else the car has been driven to get there.
Started for a second, or just the ignition on. Petrol has left your tank and got to the fuel filter and the fuel lines, because the system has been primed. Still generally easy: drain, flush, and the filter sorted.
Those few miles driven meant the pump labouring on fuel diluted by petrol the whole way. Distance is only half of it; how hard it was driven matters equally. Either way the work runs to that tank, your lines, your filter and clean fuel through the whole system. A school run to Stourfield Junior School is one matter. Getting as far as Southampton, under 25 miles away, makes a very different job — as does any distance on the M27, under 25 miles from Tuckton, with your engine working hard all the way.
Rattling, a lumpy idle, smoke, a throttle gone soft: driven until it complained. That's the motor telling you its fuel no longer is behaving like diesel. Whether it is the verge on Saxonbury Road, a lay-by or a side street, stop there and leave it. A vehicle stopped quickly very rarely has long-term damage, since the fuel drain and the flush-through, which still go first, deal with it.
What Tuckton motorists get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed by topping up — you're left with a fuller tank, still the same mix. A diesel fuel system doesn't tolerate petrol by percentage in the way that guidance supposes.
Not so: a current diesel copes with a bit of petrol. If anything, the opposite. Smaller parts and higher pressure are the way a current diesel runs its fuel, and that makes the lubrication count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that catches drivers. A petrol engine fed diesel normally won't run, so the driver stops and the harm stops with them. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, while your pump wears. Fine and running aren't the same thing.
An outdated fix for a distinct problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has diluted stays diluted, and that petrol remains in the tank regardless.
Myth: "Drain your tank yourself and you are sorted." Once the motor has been run, some of the petrol is no longer in your tank: it's in your filter and your lines, and it goes straight back through your pump at your next start. Besides, petrol emptied into a can by the road is truly risky.
How petrol ends up: petrol in a diesel
Nobody does it on purpose, and it is rarely carelessness. A diesel nozzle mostly will not fit a petrol motor, yet the smaller petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one error easy, and just in that direction.
Habit and the vehicle getting out of step is when it takes place. Any vehicle that is new to you — hired, on loan as a courtesy car, or just bought. One petrol and one diesel on the drive of the same household. Your usual forecourt, its pumps now in a different order. Rushing for a train at Christchurch and filling up en route. Exactly the moment it happens: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. With rain, a call arriving, or a car full of children to deal with, your hand simply does what it always has.
Tuckton motorists: 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, yet not on each forecourt.
- Check the filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on your first fill in a vehicle you do not know.
- A coloured fob or a sticker on your diesel's key achieves more than any amount of meaning to remember, in a household with one of each.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump. It sounds silly and it does the trick.
- Thinking about something else is when this becomes an easy mistake to make, and so put your phone away then keep your mind on the petrol pump.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler built to block a petrol nozzle, and add-on devices are available for the remainder. Treat it as a safety net, and keep reading the pump.
- As soon as you realise, stop: less petrol in your tank means a thinner mix. What to do next doesn't change, though — still do not crank it.
Tuckton: already put petrol in a diesel?
Then the order of things is brief. Don't turn the ignition on, and do not crank it. Yet at the forecourt, at Shell or anywhere else? Ask the staff to help you roll the vehicle away from the pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it's been run.
Corrosion and deposits form the problem with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and see its own Tuckton page.
Tuckton petrol in a diesel tasks: why one costs more than another
The four scenarios above are four separate tasks, so no single price for this would be fair. The situation itself does most of the work of moving your cost. Where your car is counts too, and whether our van can safely reach it, after the ratio of petrol to what the tank holds.
What was put in, how much, and if it has run — three questions our engineers ask before quoting, not after, for exactly that reason. A range turns into a straight figure once the replies are in.
About Tuckton itself
Tuckton is a coastal suburban area in Dorset, situated near the mouth of the River Stour and close to the neighbouring communities of Iford, Southbourne, and West Southbourne. Tuckton lies at a low elevation of around 5 metres, with its detached housing stock reflecting the area's residential character. Tuckton is located near the city of Southampton, which is approximately 20 miles away, and is also within commuting distance of London, around 90 miles to the east. Tuckton has a population of around 5961 people, according to recent estimates.
Tuckton and Dorset: where our fuel drain cover reaches
The vans answering petrol in diesel call-outs around Tuckton, in the BH postcode area, also work the places around it, Iford, Southbourne and West Southbourne included. Our engineers drain where the vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
In Tuckton and still at the pump?
The best place there is, then — that is where you are. Keep it off. Phone.