How Worried Should You Be? Petrol in a Diesel Car in East End
Far less than you likely are, provided it hasn't been started. "Have I ruined it?" is the first question anyone around East End asks, and the honest answer is normally no, since petrol resting in a diesel tank harms nothing until it's drawn through the fuel system — by ignition priming, by the starter, or by driving. Keep it like that: leave the engine off and ring Petrol in Diesel. Further down, this page sets out what petrol actually does inside a diesel, how far it may have gone, and how to stop it happening to you again.
Inside the engine: what petrol in a diesel really does
Passing through a motor, diesel is doing two jobs at the same time. It combusts, and before it combusts it protects. Very fine clearances go into the injectors and the high-pressure pump, and just your diesel running through stops those surfaces grinding together.
Petrol handles the first job badly and the second not at all. The rattling comes from petrol being designed not to ignite when compressed, which is precisely the opposite of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the fuel system hinges on, and any pump running on such a blend is wearing itself.
Combined, those leave the shape of the trouble clear. It is circulation that does the harm, not contact. Any tank with petrol in it is a fuel issue. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds travels on with your fuel to your injectors downstream.
Petrol in a diesel in East End: how bad is it? Four cases
Fuelled up, not once started. The best case there can be. Only the tank has petrol in it, and so the task is emptying that tank and flushing the fuel system where your car stands. This scenario can only really happen at a forecourt: anywhere else, the car got there by being driven.
A moment's running, or just your ignition on. Once primed, your system has pulled petrol from the tank up to the fuel filter and your lines. That's normally still an easy job — a drain, a flush, and the filter dealt with.
Driven a few miles. Now your pump has spent these miles working on weakened fuel. Tank, lines, filter, then clean fuel run through the whole system: that's this work, and the way the car was driven matters as much as the miles. On the school run to St Francis Catholic Primary School, the mileage is short. A run as far as Bristol, under 10 miles away, is a very different task. So is any distance on the M5, under 3 miles from East End, where the engine has been working hard the whole time.
Clattering, a lumpy idle, smoke, a throttle gone soft: driven until it complained. That is your motor telling you its fuel no longer is behaving like diesel. Leave it wherever it stops: a lay-by, a quiet street, the verge on Tetbury Gardens. What comes first is still the fuel drain and flush, and that deals with it, with long-term damage very rare when a car is stopped soon.
What East End motorists get told about petrol in a diesel — and the myths in it
False: topping up to full with diesel makes it fine. It does not. A bigger tank of the same mixture is all it gives, because topping up removes nothing. That guidance presumes a diesel fuel system tolerates petrol by percentage. It doesn't.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. Finer components and higher pressure are the way a newer diesel runs its fuel, and that makes the protection count more, not less.
Myth: "If it starts and drives, there is no damage done." This is the one that fools people. Feed diesel to a petrol motor and it normally won't run, and so the motorist stops — and the harm stops with them. While the pump grinds, a diesel fed petrol normally starts, idles and drives away as though nothing has happened. Fine and running are not the same thing.
Myth: a two-stroke additive lets you to drive home. It was an old workaround, meant for another fault. The petrol is still inside that tank after that, and what it has diluted isn't put back.
The next start draws petrol back round the pump out of your lines and your filter, where some of it sits once the engine has been run. That is why draining the tank yourself doesn't sort it — a myth. Draining petrol into a can at the roadside is also truly risky.
How petrol ends up: petrol in a diesel
It's rarely carelessness, and no one does it on purpose. The forecourt makes it simple: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, while a diesel nozzle generally will not go into a petrol car at all. So the mistake runs one way.
When habit and the car stop matching, it takes place. Hire cars, courtesy cars, and vehicles that are new to you. One petrol and one diesel on the drive of the same household. A familiar forecourt with the pumps in a different order. A rushed fill on the way to Nailsea & Backwell with a train to catch. The first fill-up in a diesel Renault Megane after years of driving petrol is exactly the moment it occurs. With rain, a call arriving, or children to deal with, the hand just does what it always has.
East End drivers: how to avoid petrol in a diesel next time
- Check the petrol pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on each forecourt. The label is what counts.
- Check your filler flap. Many vehicles state the fuel inside the flap or on the cap. Look at it on your first fill in a motor you don't know.
- One of each in the house? Mark the key to the diesel — a coloured fob, a sticker — since intending to remember is not enough.
- "Diesel", out loud, before you lift the nozzle — every time a new or hired car gets its first tank. It seems silly. It does the trick.
- Tuck the phone away. This is an easy mistake to make while 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 only, never a reason to stop checking the label.
- Spotting it halfway? Stop at once. A weaker mix results from less petrol in that tank, yet your next stage remains the same: don't fire it up.
Petrol already in a diesel around East End? Begin here
Then, there's only a short order of things. Starting it is out, and so is turning on your ignition. Ask the staff to help you roll it clear of the petrol pump if you're still at the forecourt, whether that is Tesco or somewhere else. What got in, roughly how much, and if it's run: tell us those when you call 0333 366 0103.
If it was AdBlue rather than petrol, say so. That is a different fault — corrosion and deposits rather than lost protection — and it has its own page for East End.
East End petrol in a diesel jobs: why one costs more than another
The four scenarios above are four separate tasks, so no single price for this would be honest. The situation itself does most of the work of moving your cost. Two things follow that: the petrol that went in as a proportion of what that tank holds, then the place your car is in and whether a technician can get to it safely.
That is why we ask three queries before costing instead of after: what got in, how much, and if it has run. A range turns into a straight figure once the answers are in.
About East End and where it is
East End is a suburban area in Somerset, situated inland at an elevation of 23 metres, approximately 6.5 miles from Bristol. East End has a population of around 3917 people and is characterised by predominantly detached housing. East End is located near other local places such as Backwell Common, Nailsea, and Backwell Green, and is about 112.8 miles west of London.
East End and Somerset: where our fuel drain cover runs
Petrol in diesel jobs around East End — part of the BS postcode area — go to vans that also cover the places round it, Backwell Common, Nailsea and Backwell Green included. The car doesn't need to move to us: our technicians drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
East End: still at the pump?
Nothing beats it: that is where you are. Call, and keep it turned off.