Old Town: Petrol in a Diesel Car? How Worried to Be
Provided it hasn't been started, you can worry less than you likely are. "Have I wrecked it?" is the first question anyone around Old Town asks, and the truthful answer is generally no, since petrol left in a diesel tank hurts nothing until it is dragged through the system — by ignition priming, by your starter, or by driving. Petrol in Diesel is who to call, with your engine left off, so it stays that way. The remainder of this page sets out what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you a second time.
Inside the engine: what petrol in a diesel really does
Two tasks fall to diesel on its route through a motor. It combusts, and before it ignites it lubricates. Very fine gaps go into the fuel injectors and the high-pressure pump, and only your diesel flowing through keeps their surfaces from grinding together.
Poorly at the first, not at all at the second: that is petrol. The rattling 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 depends on, and any pump working on that blend is wearing itself.
Together, those leave the shape of the issue plain. The damage is done by circulation, not by contact. A tank with petrol in it is a fuel fault. A pump that has been labouring on that petrol is the start of a mechanical one, and whatever a worn pump sheds travels on with the fuel to the injectors downstream.
Old Town, petrol in a diesel: four situations, from mild to significant
Filled up, not once started. The best case there is. Only that tank has petrol in it, so the task is emptying the tank and flushing the fuel system where your car stands. This scenario can only really occur on a forecourt: anywhere else, your car got there by being driven.
A brief spell of running, or merely your ignition on. Petrol has come out of that tank and got to the fuel filter and the lines, since your system has been bled. Normally nothing more than emptying, flushing and sorting the fuel filter, and so still straightforward.
A few miles driven, and your pump has spent every one of them working on diluted fuel. The work is the tank, the lines, your filter and clean fuel through the entire circuit, and how hard the car was driven counts as much as how far. On the school run to Sacred Heart Catholic Primary School, the miles is small. Very different again: a run to Brighton and Hove, under 50 miles away, or any mileage on the M20, under 25 miles from Old Town, where your engine never stopped working hard.
Driven till it complained. Clattering, a ragged idle, smoke, a throttle that has gone soft. What you are hearing is your motor signalling fuel that no longer behaves like diesel. Stop where you are — on the verge on Harold Road, at the kerb, down a side road — and don't move it again. The fuel drain and flush-through still come first, and they take care of it: when a car is stopped quickly, long-term damage is very uncommon.
Myths Old Town motorists hear about petrol in a diesel
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Nothing is removed by topping up — you are left with a fuller tank, still the same mix. A diesel fuel system does not accept petrol by percentage in the way that advice presumes.
"Newer diesels can handle a little petrol" — a myth, and closer to the opposite. Lubrication matters more on current diesels, not less, since their fuel runs through more precise components at higher pressure.
Myth: "If it starts and drives, there's no harm done." This is the one that fools people. The motorist of a petrol engine fed diesel normally has no choice but to stop, because it will not run, and the harm stops there. Whilst your pump grinds, a diesel fed petrol usually starts, ticks over and drives away as though nothing has happened. Running is not the same as fine.
Myth: a two-stroke additive makes it safe to drive home. It was an old workaround, meant for another issue. What petrol has weakened stays diluted, and that petrol remains in the tank regardless.
If your engine has run, part of the petrol sits in the filter and your lines, not your tank — and your next start pulls it straight back through your pump. So the myth "drain the tank yourself and you are sorted" doesn't hold. Emptying petrol into a can at the kerbside is also really risky.
Petrol in a diesel: how does it occur?
No one does it on purpose, and it's rarely carelessness. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle mostly will not go into a petrol motor at all. So the slip runs one way.
Habit and the car getting out of step is how it happens. A vehicle that's new to you — hired, on loan as a courtesy car, or just bought. One petrol and one diesel on the driveway of the same household. Your normal forecourt, its pumps suddenly in a different order. Fuelling up in a rush en route to Ore, with a train to catch. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. With rain, a call coming in, or children to deal with, your hand simply does what it always has.
How to prevent petrol in a diesel on your next fill-up around Old Town
- Green for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Go by the label on the pump, not the colour.
- Check the filler flap. Plenty of motors state the fuel inside the flap or on the cap. Look at it on your first fill in a car you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of intending to remember, in a household with one of each.
- Before the nozzle comes off the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Daft, perhaps, but it does the trick.
- Put your phone away. This is an easy mistake to make whilst you are thinking about something else.
- Add-on devices are available for cars without one, and some diesels are built with a filler that will not accept a petrol nozzle. Helpful — but a backstop at best, never a reason to stop checking the label.
- Noticing it halfway? Stop there and then. A weaker mix follows from less petrol inside that tank, yet your next stage stays the same: do not start it.
Old Town: already put petrol in a diesel?
Then the order of things is short. Leave it unstarted, with your ignition off too. Ask the staff to help you roll it clear of the pump if you're still at the forecourt, whether that is Texaco or somewhere else. Call 0333 366 0103 next, with three facts — the fuel, the rough volume, and if it has run.
If it was AdBlue instead of petrol, say so. That is a different problem — corrosion and deposits rather than lost lubrication — and it has its own page for Old Town.
Old Town petrol in a diesel tasks: why one costs more than another
There's no honest single price for this, since the four situations above are four separate tasks. The situation itself does most of the work of moving the cost. The share counts next, meaning how much of the tank is petrol, followed by the position of the vehicle and whether reaching it is safe for our van.
Before any quote, not after, come three questions: your fuel that was put in, its amount, and whether it has run. That's why. The answers change a range into a straight figure.
About Old Town, for a moment
Old Town is a suburban area in East Sussex, situated on the coast at an elevation of 21 metres. Old Town lies approximately 54.6 miles south of London and 32.3 miles east of Brighton and Hove, near neighbouring areas such as High Wickham and West Hill. Old Town is characterized by its predominantly terraced housing stock, reflecting the typical architectural style of many coastal towns in the South East. Old Town forms part of a larger conurbation that includes nearby Broomsgrove and other local communities.
Fuel drain cover across East Sussex, Old Town included
Petrol in diesel jobs around Old Town — part of the TN postcode area — go to vans that also cover the locations about it, High Wickham, West Hill and Broomsgrove included. A forecourt, a supermarket car park, a lay-by or your own driveway are all locations our engineers work, and the vehicle doesn't need to come to us.
In Old Town and still at the pump?
Then you are in the best position there can be. Leave the vehicle switched off, and ring.