Should You Worry? Petrol in a Diesel Car in Harlow Common
Not started? Then less worried than you probably feel. "Have I ruined it?" is the first question everyone around Harlow Common asks, and the honest answer is generally no, since petrol left in a diesel tank harms nothing until it's dragged through the fuel system — by ignition priming, by your starter, or by being driven. Petrol in Diesel is who to phone, with your motor kept off, and so it stays that way. The rest of this page sets out what petrol really does to a diesel, how to judge how far it has got, and how to make sure it does not happen to you again.
Petrol in a diesel: what does it do to the engine?
Diesel does two tasks on its way through an engine. It ignites, and before it ignites it protects. Designed to very fine tolerances, the injectors and the pump depend on your diesel moving through them to keep their surfaces from wearing against one another.
The second task petrol does not do at all, and the first it does badly. The knocking comes from petrol being made not to ignite when compressed, which is precisely the reverse of what a diesel needs. On top of that it is thinner than diesel, it strips out the lubrication the system hinges on, and any pump running on such a blend is wearing itself.
Put these together and the shape of the trouble is plain. It's movement that does the harm, not contact. Petrol in a tank is a fuel issue. Once your pump has been running on that petrol, a mechanical issue has started: whatever is shed by a pump that is wearing down is carried downstream to the injectors with your fuel.
Harlow Common, petrol in a diesel: four cases, from mild to significant
Fuelled but never started — as good as it gets. On a forecourt, and truly only there, the petrol is still confined to that tank — since everywhere else the car was driven to reach it. The task is draining and purging on the spot.
Started for a moment, or only the ignition on. With your system primed, the lines and filter already contain petrol that came from your tank. That is usually still a simple task — a drain, a flush, and your filter seen to.
Those few miles driven were your pump labouring on fuel thinned by petrol throughout. Tank, lines, filter, then fresh fuel run through the entire system: that is the work, and the way the car was driven counts as much as the distance. A school run to Potter Street Academy is one matter. A run as far as Chelmsford, under 15 miles away, is a very different task. So is any miles on the M11, under a mile from Harlow Common, where the motor has been labouring hard throughout.
Clattering, an uneven idle, smoke, a throttle gone soft: driven until it complained. What you are hearing is the engine reporting fuel that no longer acts like diesel. Pull up wherever you are — the verge on Latton Street, a lay-by, a side street — and leave it there. The fuel drain and flush-through still come first, and they deal with it: when a car is pulled over early, long-term damage is very uncommon.
What Harlow Common motorists get told about petrol in a diesel — and the myths in it
It will not be fine. The myth: "Fill it the rest of the way with diesel and it will be." Topping up removes nothing; it gives you a bigger tank of the same mixture. A diesel fuel system doesn't accept petrol by percentage in the way that advice supposes.
If anything, the reverse holds. Myth: "A current diesel can cope with a bit of petrol." At higher pressure, through smaller parts: that is how a current diesel handles its fuel, and so the lubrication counts more, not less.
"It starts, it drives, so no harm done" — the myth that trips up most drivers than any other. The driver of a petrol engine fed diesel usually has no choice but to stop, because it will not run, and the harm stops there. Feed petrol to a diesel and it usually fires up, ticks over and drives away like nothing has happened — all the while its pump is wearing. A running engine does not mean fine.
"A drop of two-stroke oil and drive it home" — a myth, borrowed from a fix from years ago, for a distinct problem. It doesn't put back what petrol has thinned, and the petrol is still in the tank later on.
Once the engine has run, part of the petrol is in your filter and the lines, not your tank — and the next start pulls it straight back through the pump. So the myth "drain your tank yourself and you are sorted" does not hold. Draining petrol into a can by the roadside is also truly hazardous.
Petrol in a diesel: how does it take place?
It's rarely carelessness, and nobody does it on purpose. The forecourt makes it simple: the petrol nozzle is the smaller of the two, and it slides into a diesel filler with almost no resistance, while a diesel nozzle generally will not go into a petrol car at all. So the slip runs one way.
Routine and the vehicle getting out of step is when it occurs. Hire cars, courtesy cars, and motors that are new to you. One petrol and one diesel on the drive of the same household. The pumps in a different order on a well-known forecourt. Fuelling up in a hurry on the way to Harlow Town, with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Passat in front of you on the forecourt for its first tank — that is when. Add a back seat full of children, a phone call or rain, and habit takes over.
How to avoid petrol in a diesel at your next fill-up in Harlow Common
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Read the pump's label; the colour is just a hint.
- Inspect the filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on the first fill in a motor you do not know.
- Mark your key. In a house with one of each, a coloured fob or a sticker on the diesel's key does more than any amount of intending to remember.
- Before the nozzle leaves the petrol pump the first time you fill a hired or new car, say "diesel" out loud. Daft, yes, but it does the trick.
- Tuck the phone away. This is an easy mistake to make while you are thinking about something else.
- Up to a point, a misfuel inhibitor helps: some diesels have a filler designed to block a petrol nozzle, and aftermarket devices are available for the rest. Count it as a backstop, then keep checking the petrol pump.
- Less petrol makes a weaker mix, and so stop the moment you realise — while remembering that your next step is unchanged. It's still not to crank it.
Put petrol in a diesel in Harlow Common already?
Short and simple, then, is the order of things. Never crank it, and do not switch your ignition on. Still at the forecourt, at BP or anywhere else? Ask the attendants to help you push the car away from the petrol pump. Next, 0333 366 0103. We will ask what got in, roughly how much, and if it has been run.
Say so if it was AdBlue instead of petrol: it is a different problem, with its own page for Harlow Common, because AdBlue brings corrosion and deposits instead of lost protection.
What makes one Harlow Common petrol in a diesel task cost more than the next
The four situations above are four separate tasks, so no single price for this would be honest. What moves the cost is chiefly which of them you are in. Next it's the share — how much petrol went in against how much that tank takes — and then where the car is and whether a technician can get to it safely.
What went in, how much, and whether it has run — three questions our technicians ask before pricing, not after, for exactly that reason. A range turns into a straight figure when the answers are in.
About Harlow Common
Harlow Common is a suburban area in Essex, situated approximately 20 miles northeast of London and 15 miles west of Chelmsford. Harlow Common sits at an elevation of around 100 metres, near the communities of Potter Street, Latton Bush, and Foster Street. Harlow Common has a population of around 2072 people, predominantly living in terraced housing.
Across Essex and around Harlow Common: fuel drain cover
The teams answering petrol in diesel calls in Harlow Common, in the CM postcode area, also work the locations near it, Potter Street, Latton Bush and Foster Street among them. We drain wherever your vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
In Harlow Common and still at the pump?
Then you are in the best place there can be. Turned off it remains; then ring.