Petrol in a Diesel Car in Somerton: How Worried Should You Be?
Likely less than you are now — provided nobody has started the vehicle. Petrol sitting in a diesel tank does nothing to your motor till something pulls it through your fuel system — your ignition priming the pump, the starter, or the drive itself. So the truthful answer to the first question everyone around Somerton asks, "have I ruined it?", is usually no. Leave the engine off then ring Petrol in Diesel — that keeps it like that. Below, this page sets out what petrol actually does inside a diesel, how far it may have got, and how to stop it happening to you a second time.
Petrol in a diesel: what does it do to the engine?
Two jobs fall to diesel on its route round a motor. Before it burns, it lubricates — then it combusts. The high-pressure pump and the fuel injectors are made to extremely fine clearances, and the diesel passing through them is what keeps those surfaces from wearing down against each other.
The second job petrol does not do at all, and the first it does badly. A pump working on a petrol blend is wearing itself out, since petrol is runnier than diesel and takes away 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 is where the rattling starts.
Put these together and the shape of the issue is plain. Not contact but movement is what causes the damage. Where the petrol is only inside your tank, it's a fault of fuel, nothing more. Whatever a worn pump sheds goes on, borne by your fuel, into your injectors further along, which is why a pump that has worked on that petrol is where a mechanical problem begins.
Somerton, petrol in a diesel: four cases, from mild to significant
The best case there can be: filled up, never started. Only the tank has petrol in it, and so the task is clearing your tank and purging the fuel system where your car sits. This situation can only really occur at a forecourt: anywhere else, the car got there by being driven.
Your ignition switched on, or a short start. The fuel system has been bled, so petrol has left that tank and reached the filter and the lines. Usually nothing more than clearing, cleaning and sorting the filter, and so still straightforward.
A few miles driven, and the pump has spent every one of them working on diluted fuel. Mileage is only half of it; how hard it was driven matters equally. Either way the work runs to your tank, your lines, the fuel filter and fresh fuel through the whole system. A school run to King Ina Church of England Academy is one matter. A run as far as Wells, under 15 miles away, is a very different job. So is any miles on the M5, under 15 miles from Somerton, where the engine has been working hard throughout.
Driven on till it complained — rattling, smoke, a ragged idle, a soft throttle. What you are hearing is your motor signalling fuel that no longer runs like diesel. Stop where you are — on the verge on West Street, at the kerb, down a side road — and do not move it again. Permanent damage is very uncommon when a car is pulled over soon, and the fuel drain and flush that still go first sort it out.
Petrol in a diesel stories Somerton motorists hear
False: topping up to full with diesel makes it fine. It does not. A bigger tank of the same mix is all you get, since topping up removes nothing. That guidance presumes a diesel fuel system tolerates petrol by percentage. It doesn't.
"Newer diesels can handle a little petrol" — a myth, and closer to the reverse. Smaller parts and higher pressure are the way a modern diesel runs its fuel, and that makes the protection matter more, not less.
Myth: "If it starts and drives, there's no harm done." This is the one that catches people. Diesel in a petrol motor generally leaves a motor that won't run: the motorist stops, and so does the harm. A diesel fed petrol normally starts, idles and drives away as if nothing has happened, while the pump wears. A running engine doesn't mean fine.
Myth: "Add some two-stroke oil and drive it home." It's an old fix for a distinct problem. The petrol is still in that tank afterwards, and whatever it has diluted is not put back.
"Drain it yourself and you're 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. It's also really hazardous to drain petrol into a can at the kerbside.
How petrol ends up: petrol in a diesel
On purpose? Never. Through carelessness? Seldom, if ever. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle generally will not go into a petrol car at all. The forecourt makes it easy, and the slip runs one way.
Habit and your car getting out of step is when it takes place. Courtesy car, hire car, or a car that is new. Households running one of each, petrol and diesel. A well-known forecourt with the pumps in a different order. Racing for a train outside Yeovil Pen Mill and filling up en route. Precisely the moment it happens: after years of driving petrol, a driver fills a diesel Volkswagen Golf for the first time. Your hand repeats what it has always done when you add rain, a phone call or a back seat full of children.
How to avoid petrol in a diesel on your next fill-up around Somerton
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most generally do. Read the petrol pump's label; the colour is only a hint.
- Many vehicles state the fuel inside your filler flap or on the cap, and so check it on the first fill in a motor you don't know.
- A coloured fob or a sticker on the diesel's key does more than any amount of meaning to remember, for a house with one of each.
- It sounds daft and it works: on the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the petrol pump.
- Tuck your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Some diesels come with a filler designed to reject a petrol nozzle, and devices you can add are available for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Less petrol means a thinner mix, and so stop as soon as you notice — while remembering that your next step is unchanged. It is still not to start the car.
Put petrol in a diesel in Somerton already?
The order of things is short, then. Leave it unstarted, with your ignition off as well. Yet on the forecourt, at Esso or anywhere else? Ask the attendants to help you roll the vehicle away from the pump. What went in, about how much, and whether it's run: tell us that when you call 0333 366 0103.
If it was AdBlue rather than petrol, say so. That is a separate fault — corrosion and deposits and not lost protection — and it has its own page for Somerton.
One petrol in a diesel task in Somerton costs more than another. Why?
A fair single quote does not exist here: four scenarios, four separate tasks. What shifts the cost is mostly which of them you're in. Where the car is matters too, and whether our van can safely get to it, after the share of petrol to what the tank holds.
Before any quote, not after, we ask three queries: your fuel that was put in, the amount, and whether it's run. That's why. Given the answers, you get a straight figure rather than a range.
About Somerton
Somerton is a town situated on the River Parrett in Somerset, with a low elevation of around 38 metres above sea level. Somerton lies near the towns of Wells and Langport, and is surrounded by smaller settlements like Behind Berry and West End. Somerton has a mix of housing types, but semi-detached homes are particularly prevalent. Somerton is located in the South West region of England, approximately 116.9 miles west of London.
Fuel drain cover around Somerton and across Somerset
Behind Berry, West End and Lower Somerton are among the places near Somerton that the same vans work, answering petrol in diesel call-outs across Somerton's TA postcode area. The car does not need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
At the petrol pump in Somerton, still?
In that case, you couldn't be in a better place. Leave it turned off, then ring.