How Worried Should You Be? Petrol in a Diesel Car in Southville
Probably less than you already are — as long as nobody has started the vehicle. Petrol sitting in a diesel tank does nothing to your engine till something pulls it through the fuel system — the ignition priming your pump, the starter, or driving on its own. So the honest answer to the first query everyone in Southville asks, "have I wrecked it?", is usually no. To leave the vehicle like that, ring Petrol in Diesel and leave your engine switched off. The remainder of this page sets out what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Inside the motor: what petrol in a diesel really does
Two tasks fall to diesel on its journey round a motor. Lubricating comes before burning; it does both. Extremely fine gaps are built into your injectors and the high-pressure fuel pump, and just your diesel flowing through stops their surfaces grinding together.
Petrol handles the first task badly and the second not at all. The knocking comes from petrol being made not to ignite when compressed, which is exactly the reverse of what a diesel needs. On top of that it is runnier than diesel, it strips away the lubrication the system hinges on, and any pump working on that mixture is wearing itself.
Put those together and the shape of the issue is plain. Contact doesn't do the harm — circulation does. Where the petrol is only in that tank, it is a fault of fuel, nothing more. Whatever a worn pump sheds goes on, borne by the fuel, into the injectors downstream, which is why a pump that has been working on the petrol is where a mechanical fault begins.
How serious is petrol in a diesel? Four scenarios our engineers see in Southville
Fuelled but not once started — as good as it gets. Being at a forecourt is what makes this the case: elsewhere, the car has been driven there to begin with. With the petrol kept in your tank alone, it is cleared and purged on the spot, and nothing more is needed.
Your ignition turned on, or a short start. The system has been primed, so petrol has left that tank and got to the filter and the fuel lines. That's normally still an easy job — a drain, a flush, and your filter dealt with.
Those few miles driven were the pump labouring on fuel thinned by petrol the whole way. The work is your tank, your lines, your filter and fresh fuel through the entire system, and how hard the car was driven matters as much as how far. Short trips, like the school run to the local primary school, are one matter. Any miles on the M4, under 5 miles from Southville, means your engine working hard throughout, and a run to Newport, under 5 miles away, makes a very different job too.
Driven on until it complained — rattling, smoke, a lumpy idle, a soft throttle. What you are hearing is the motor signalling fuel that no longer behaves like diesel. Pull up wherever you are — the verge on Whitebrook Way, a lay-by, a side street — and leave the vehicle where it is. A vehicle pulled over early very seldom has long-term damage, as the fuel drain and the flush-through, which still come first, sort it out.
Myths Southville motorists hear about petrol in a diesel
Myth: topping up to full with diesel makes it fine. It does not. A bigger tank of the same mixture is all you get, because topping up removes nothing. Percentage isn't how a diesel fuel system copes with petrol, however much that guidance assumes.
Myth: a current diesel copes with a bit of petrol. Rather, the reverse. A newer diesel sends its fuel through smaller components at higher pressure, which makes the protection matter more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that catches people. Diesel in a petrol motor generally means a motor that won't run: the motorist stops, and so does the damage. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually does; meanwhile the pump wears. Running isn't the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a different issue. That petrol is still inside your tank afterwards, and what it has diluted is not put back.
"Drain it yourself and you're sorted" — a myth, because after it's been running some petrol lies in the filter and lines, ready to go straight back through the pump at the next start. Also, a can of petrol drained at the kerbside is truly hazardous.
Petrol in a diesel: how does it take place?
Carelessness is rarely the cause, and nobody means to do it. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one generally won't fit a petrol motor. That's how the forecourt makes it easy.
The moment habit stops matching the vehicle is the moment it takes place. A new vehicle, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. The pumps in a different order on a well-known forecourt. A train to catch, and a rushed fill en route to Cwmbran. Years of petrol motors behind you, a diesel Volkswagen Tiguan in front of you on the forecourt for its first tank — that's when. Add rain, a phone call or a back seat full of children, and the hand does what it has always done.
Next time you fill up around Southville: preventing petrol in a diesel
- Check the petrol pump, not the colour. In the UK unleaded handles are usually green and diesel black, yet not on each forecourt. The label is what counts.
- The first fill in a new car is the time to check your filler flap — on it, or on the cap, many vehicles state the fuel to use.
- Label your key. In a home with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- Before the nozzle comes off the pump the first time you fill a hired or new vehicle, say "diesel" out loud. Silly, yes, yet it does the trick.
- While you are thinking about something else, this is an easy mistake to make — so put your phone away.
- Add-on devices exist for cars without one, and some diesels are built with a filler that won't take a petrol nozzle. Useful — but a safety net only, never a reason to stop checking the label.
- Less petrol makes a thinner blend, and so stop the moment you notice — though remembering that the next stage is unchanged. It is still not to fire it up.
Petrol already in a diesel in Southville? Begin here
Then the order of things is brief. Don't start it, and don't turn your ignition on. Ask the attendants to help you push it clear of the pump if you're still on the forecourt, whether that is Sainsbury's or somewhere else. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it's been run.
Say so if it was AdBlue rather than petrol: it's a different problem, with its own page for Southville, because AdBlue brings corrosion and deposits rather than lost lubrication.
Southville petrol in a diesel tasks: why one costs more than another
A fair single price does not exist here: four situations, four separate jobs. The situation itself does most of the work of moving your cost. Where your car is counts too, and whether a technician can safely reach it, after the ratio of petrol to what that tank takes.
That is why our engineers ask three questions before pricing rather than after: what was put in, how much, and whether it's run. Their replies are what turn a range into one firm number.
About Southville and its setting
Southville is a suburban area in Torfaen, Wales, situated on the riverside at an elevation of 55 metres. Southville lies close to the city of Newport, approximately 4.3 miles away, and is near other local places such as Old Cwmbran and Cwmbran. Southville has a population of around 2504 people and is characterised by predominantly terraced housing. Southville is located within commuting distance of major cities, with London being around 124.6 miles away.
Across Torfaen and in Southville: fuel drain cover
Old Cwmbran, Cwmbran and Northville are among the locations around Southville that the same teams work, answering petrol in diesel jobs across Southville's NP postcode area. You need not bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
In Southville and still at the pump?
Then, you could not be in a better position. Switched off it stays; then phone.