Coalmakers Wharf: Petrol in a Diesel Car? How Worried to Be
If it has not been started, you can worry less than you probably are. "Have I ruined it?" is the first thing everyone in Coalmakers Wharf asks, and the honest answer is normally no, because petrol resting in a diesel tank hurts nothing till it is dragged through your fuel system — by ignition priming, by the starter, or by driving. Petrol in Diesel is who to ring, with the engine kept off, so it stays that way. The rest of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it doesn't happen to you a second time.
Petrol in a diesel: what does it do to the engine?
On its way through an engine, diesel has two jobs. It burns, and before it ignites it protects. Designed to extremely fine gaps, the fuel injectors and the pump rely on the diesel moving through them to stop their surfaces wearing against one another.
Of these two jobs, petrol handles the first poorly and the second not at all. It's thinner than diesel and takes away the lubrication your fuel system rests on, so a pump running on a petrol blend is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the clattering comes from.
Seen together, they make clear the shape the trouble takes. Contact does not do the damage — circulation does. A tank with petrol in it is a fuel fault. Whatever a worn pump sheds travels on, carried by your fuel, into the fuel injectors further along, which is why a pump that has worked on that petrol is where a mechanical issue starts.
Petrol in a diesel in Coalmakers Wharf: how serious is it? Four cases
Filled up, and not started: nothing beats it. The petrol is inside that tank and only the tank, and the job is a drain and a flush where your car stands. This is the one scenario that can only truly occur on a forecourt, since anywhere else the vehicle has been driven to get there.
A brief spell of running, or just your ignition on. With your system primed, your lines and filter already hold petrol that came from your tank. Still normally simple: drain, flush, and the fuel filter sorted.
Those few miles driven meant the pump labouring on fuel weakened by petrol the whole way. How hard the vehicle was driven matters as much as how far, and the work covers your tank, the lines, your filter and fresh fuel through the whole circuit. Driving the kids to Stebon Primary School is one sort of trip. Any distance on the M11, under 10 miles from Coalmakers Wharf, means the engine working hard throughout, and a run to London, under 3 miles away, makes a very different task too.
Driven on till it complained — knocking, smoke, a lumpy idle, a dead throttle. The motor is telling you the fuel is no longer acting like diesel. Pull up where you are — on the verge on Coalmakers Wharf, at the kerb, down a side road — and don't move it. Long-term damage is very uncommon when a car is pulled over early, and the drain and flush-through that still go first take care of it.
Myths Coalmakers Wharf motorists hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. A fuller tank of the same mixture is all you get, because topping up removes nothing. The assumption behind the guidance — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the opposite. A modern diesel runs its fuel through finer parts at higher pressure, which makes the protection count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that catches motorists. Any petrol engine fed diesel normally will not run, and so the driver stops and the damage stops with them. Whilst the pump grinds, a diesel fed petrol usually starts, idles and drives away as though nothing has happened. A running engine doesn't mean fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It's an old fix for a different fault. None of what petrol diluted gets put back by it — and afterwards, your tank still contains the petrol.
Myth: "Drain your tank yourself and you are sorted." After your engine has been run, some of that petrol is no longer inside that tank: it is in the fuel filter and the fuel lines, and it goes straight back through the pump on the next start. On top of that, petrol drained into a can by the road is truly dangerous.
Petrol in a diesel: how does it happen?
Carelessness is rarely the cause, and nobody means to do it. One way only, because of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one generally won't fit a petrol vehicle. That is how the forecourt makes it easy.
When routine and your car stop matching, it happens. Any car that's new to you — hired, on loan as a courtesy car, or just bought. Households running one of each, petrol and diesel. Your usual forecourt, its pumps suddenly in a different order. Filling up in a hurry en route to Limehouse, 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. With rain, a call arriving, or a car full of children to deal with, your hand just does what it has always done.
How to avoid petrol in a diesel on your next fill-up in Coalmakers Wharf
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most usually do. Check the pump's label; the colour is only a hint.
- In a motor you do not know, look inside the flap over the filler or at the cap before your first fill: plenty of motors print the fuel type there.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key if a house has one of each. So mark it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It seems silly and it works.
- Tuck your phone away. This is an easy mistake to make while you're thinking about something else.
- Add-on devices are available for vehicles without one, and some diesels come with a filler that won't take a petrol nozzle. Helpful — but a backstop only, never a reason to stop checking the label.
- The moment you realise, stop: less petrol inside your tank means a weaker blend. What to do next does not change, though — still do not fire it up.
Petrol already in a diesel around Coalmakers Wharf? Start here
Short and simple, then, is the order of things. Starting it is out, and so is turning on the ignition. If you're still on the forecourt — Texaco or anywhere else — ask the staff to help you roll it away from the pump. Next, 0333 366 0103. We will ask what went in, about how much, and if it has been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a different fault — Coalmakers Wharf has a page all for it.
Why one petrol in a diesel job in Coalmakers Wharf costs more than another
The four scenarios above are four separate jobs, so no single price for this would be fair. The situation itself does most of the work of moving your cost. Where the car is counts too, and whether our van can safely get to it, after the ratio of petrol to what the tank holds.
Three questions come first, before quoting, rather than after — what was put in, how much, has it run — and this is the reason. Those replies are what change a range into one firm number.
About Coalmakers Wharf, briefly
Coalmakers Wharf is a locality situated on the riverside in Greater London, with a low elevation of around 4 metres above sea level. Coalmakers Wharf is located near the city of London, approximately 2.8 miles away, and is close to nearby places such as Bow Common and Limehouse. Coalmakers Wharf is predominantly composed of flat housing, which accommodates a population of around 18369 residents. Coalmakers Wharf is part of the wider London urban area, with the city centre just a short distance away.
Across Greater London and around Coalmakers Wharf: fuel drain cover
Coalmakers Wharf waits in the E postcode area, and our teams that answer petrol in diesel calls there work the places around it as well — Bow Common, Limehouse and Frank Whipple Estate among them. No need to bring the vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all spots where we work.
In Coalmakers Wharf and still at the petrol pump?
The best position there is, then — that's where you are. Turned off it remains; then call.