Should You Worry? Petrol in a Diesel Car in Old Oak Common
Provided it has not been started, you can worry far less than you likely are. Until the ignition primes the pump, your starter turns, or your vehicle is driven, petrol in a diesel tank just waits there and does nothing. Which means the honest reply to that first Old Oak Common query — "have I wrecked it?" — normally no. Keep it like that: leave the motor off and call Petrol in Diesel. Read on for three things: the effect petrol has inside a diesel motor, the clues of how far it has spread, and the way to make sure you don't do it again.
Inside the motor: what petrol in a diesel really does
On its way through a motor, diesel has two jobs. Oiling comes before burning; it does both. What keeps the surfaces inside the high-pressure pump and your injectors from grinding against each other is your diesel passing through them — they're designed to very fine tolerances.
Petrol does the first task badly and the second not at all. It is runnier than diesel and takes away the lubrication the fuel system hinges on, and so a pump running on a petrol blend is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the rattling comes from.
The shape of the problem is plain when you put those together. Contact does not do the harm — movement does. All a tank with petrol in it amounts to is a fuel issue. The beginning of a mechanical problem is a pump that has been running on that petrol — and whatever a worn pump sheds moves on with the fuel to the injectors downstream.
Four scenarios our engineers see around Old Oak Common: how bad is petrol in a diesel?
The best case there is: filled up, never started. Just the tank has petrol in it, so the task is draining that tank and cleaning the fuel system where the vehicle stands. This situation can only really take place on a forecourt: anywhere else, the car got there by being driven.
Started for a second, or just your ignition on. With your system primed, the fuel lines and filter now contain petrol that came from your tank. Still generally simple: drain, flush, and your filter seen to.
Some miles driven, and your pump has spent each of them working on thinned fuel. Tank, lines, filter, then fresh fuel put through the entire circuit: that is the work, and the way your car was driven counts as much as the miles. On the school run to John Perryn Primary School, the distance is small. A run as far as Westminster, under 10 miles away, is a very different task. So is any mileage on the M4, under 3 miles from Old Oak Common, where the engine has been labouring hard the whole time.
Driven till it complained. Knocking, a ragged idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer behaving like diesel. Stop on the spot — on the verge on Old Oak Common Lane, at the kerb, down a side road — and do not move it again. Permanent damage is very unusual when a vehicle is pulled over quickly, and the drain and flush that still come first sort it out.
Myths Old Oak Common motorists hear about petrol in a diesel
False: topping up to full with diesel makes it fine. It does not. Nothing is removed by topping up — you're left with a fuller tank, still the same mixture. Percentage isn't how a diesel fuel system copes with petrol, however much that guidance supposes.
"Current diesels can handle a little petrol" — a myth, and nearer the reverse. More precise parts and higher pressure are the way a current diesel runs its fuel, and that makes the protection matter more, not less.
One myth that catches people out: if it starts and drives, it must be unharmed. Any petrol engine fed diesel normally won't run, so the motorist stops and the damage stops with them. A diesel fed petrol generally starts, ticks over 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 the vehicle home." It is an outdated fix for a different fault. None of what petrol thinned is put back by it — and afterwards, that tank still contains the petrol.
The next start sends petrol back round the pump out of the fuel lines and the fuel filter, where some of that sits after your engine has run. That is why a DIY tank drain doesn't sort it — a myth. Besides, petrol emptied into a can by the road is truly dangerous.
How it happens: petrol in a diesel
It is rarely carelessness, and no one does it on purpose. The petrol nozzle is the narrower of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol vehicle at all. The forecourt makes it easy, and the error runs one way.
The moment routine stops matching the car is the moment it takes place. Any car that is new to you — hired, on loan as a courtesy car, or just bought. A household with one petrol and one diesel on the drive. A forecourt you know, but with its pumps arranged differently. A train to catch, and a hurried fill en route to Willesden Junction. Precisely the moment it happens: after years of driving petrol, someone fills a diesel Volkswagen Golf for the first time. Add rain, a phone call or a back seat full of children, and the hand repeats what it has always done.
Next time you fill up around Old Oak Common: preventing petrol in a diesel
- Not every forecourt in the UK follows green for unleaded and black for diesel, though most usually do. Check the petrol pump's label; the colour is just a hint.
- The first fill in an unfamiliar car is the time to check the filler flap — inside it, or on the cap, many motors state the fuel to use.
- Mark the key. In a home with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- It sounds silly and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump.
- Tuck the phone away. This is an easy mistake to make whilst you are thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels come with a filler built to block a petrol nozzle, and aftermarket devices are available for the remainder. Count it as a safety net, then keep checking the petrol pump.
- Less petrol makes a weaker mixture, and so stop the moment you notice — while remembering that the next step is unchanged. It's still not to fire it up.
Old Oak Common: already put petrol in a diesel?
The order of things is short, then. Starting it is out, and so is turning on the ignition. If you are still at the forecourt — Asda or anywhere else — ask the staff to help you push it away from the pump. Next, 0333 366 0103. We'll ask what was put in, about how much, and if it has been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a different problem — Old Oak Common has a page all for it.
Why one petrol in a diesel job in Old Oak Common costs more than another
The four situations above are four different tasks, so no single quote for this would be fair. Chiefly, the cost moves with which one you're in. Next it's the ratio — how much petrol was put in against how much that tank takes — and then where the car is and whether a technician can reach it safely.
That's why our technicians ask three questions before pricing instead of after: what got in, how much, and whether it has run. A range becomes a straight figure when those answers are in.
About Old Oak Common and where it is
Old Oak Common is a suburban area in west London, situated near the River Thames and close to the Grand Union Canal. Old Oak Common sits at an elevation of around 33 metres, with nearby North Acton and East Acton also forming part of the local residential landscape. Old Oak Common is predominantly composed of flat dwellings, housing a population of approximately 5812 residents. Old Oak Common is located near the outskirts of central London, about 5.5 miles from the city centre.
Across Greater London and around Old Oak Common: fuel drain cover
Petrol in diesel call-outs in Old Oak Common — part of the NW postcode area — go to teams that also cover the places about it, North Acton, East Acton and Lower Place included. A forecourt, a supermarket car park, a lay-by or your own driveway are all places our technicians drain, and the car doesn't need to move to us.
Still at the pump around Old Oak Common?
The best position there is, then — that's where you are. Leave the car switched off, and ring.