How Worried Should You Be? Petrol in a Diesel Car in Kingston
Likely less than you already are — as long as nobody has started the car. "Have I ruined it?" is the first thing everyone in Kingston asks, and the truthful answer is normally no, because petrol left in a diesel tank hurts nothing till it is dragged through your fuel system — by ignition priming, by your starter, or by driving. Leave the engine off then phone Petrol in Diesel — that is how you keep it 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.
What petrol in a diesel does to the engine
Diesel has two jobs on its way through a motor. Oiling comes before burning; it does both. What stops the surfaces inside the high-pressure pump and the injectors from wearing against each other is the diesel passing through them — they're built to very fine gaps.
Of those two tasks, petrol handles the first poorly and the second never. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, so a pump running on that mixture wearing itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the rattling.
The shape of the issue is clear once you put those together. Not contact but movement is what does the harm. All a tank with petrol in it amounts to is a fuel fault. The beginning of a mechanical problem is a pump that has been labouring on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
How serious is petrol in a diesel? Four scenarios our technicians see in Kingston
Fuelled, and never started: nothing beats it. The petrol is inside that tank and just that tank, and the task is a drain and a flush where the vehicle stands. This is the one scenario that can only really happen at a forecourt, as anywhere else the car has been driven to get there.
Ignition on, or started for a moment. Petrol has left your tank and reached the fuel filter and the lines, because your system has been bled. Drain, flush, deal with your filter: still normally simple.
Driven a few miles. Now your pump has spent these miles running on thinned fuel. How hard your car was driven counts as much as how far, and the work takes in your tank, your lines, the fuel filter and clean fuel through the entire circuit. Short trips, such as the school run to Linden Road Academy and Hearing Impaired Base, are one thing. Any distance on the M67, under a mile from Kingston, means your engine working hard throughout, and a run to Manchester, under 10 miles away, is a very different task too.
Driven on till it complained — rattling, smoke, a lumpy idle, a soft throttle. What you are hearing is your engine reporting fuel that no longer behaves like diesel. Leave it where it has stopped: a lay-by, a side street, the verge on Frances Street West. What goes first is still the fuel drain and flush-through, and that takes care of it, with permanent damage very rare if a vehicle is stopped early.
What Kingston people get told about petrol in a diesel — and the myths in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed by topping up — you're left with a bigger tank, still the same mix. Percentage is not how a diesel fuel system copes with petrol, whatever that advice supposes.
If anything, the opposite holds. Myth: "A newer diesel can cope with a bit of petrol." Protection counts more on modern diesels, not less, because their fuel runs through smaller components at higher pressure.
Myth: "If it starts and drives, there's no damage done." This is the one that catches drivers. Feed diesel to a petrol engine and it generally will not run, and so the motorist stops — and the damage stops with them. A diesel fed petrol usually starts, ticks over and drives away as though nothing has happened, whilst your pump grinds. Running 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 different problem. None of what petrol weakened gets put back by it — and afterwards, your tank still holds that petrol.
The next start sends petrol back round the pump from the fuel lines and the filter, where some of that sits once the engine has been run. That's why draining the tank yourself does not sort it — a myth. On top of that, petrol drained into a can by the road is genuinely risky.
How does petrol in a diesel occur?
It's rarely carelessness, and nobody 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 generally will not go into a petrol car at all. The forecourt makes it simple, and the mistake runs one way.
When habit and the car stop matching, it occurs. Courtesy car, hire car, or a car that is new. Two motors on one driveway, one petrol, one diesel. Your usual forecourt, its pumps now in a different order. Fuelling up in a hurry en route to Hyde Central, with a train to catch. A new-to-you diesel Renault Megane, its first fuelling, and a motorist used to petrol: exactly when it occurs. Add a back seat full of kids, a phone call or rain, and habit wins.
How to prevent petrol in a diesel at your next fill-up in Kingston
- The label is what counts, so read the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, but not on every forecourt.
- 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 state the fuel type there.
- Label 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.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you take the nozzle off the pump. It sounds daft and it does the trick.
- Mistakes like this are simple to make whilst your mind is on something else, so the phone goes away.
- Some diesels have a filler designed to block a petrol nozzle, and devices you can add are available for motors without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the petrol pump.
- The moment you realise, stop: less petrol inside the tank means a weaker blend. What to do next does not change, though — still don't fire it up.
Kingston: already put petrol in a diesel?
Then, there is just a short order of things. Starting it is out, and so is turning on your ignition. If you're still on the forecourt — Morrisons or anywhere else — ask the attendants to help you roll the car clear of the pump. Next, 0333 366 0103. We will ask what got in, roughly how much, and if it's been run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost lubrication, make it a separate issue — Kingston has a page all for it.
Why one petrol in a diesel job in Kingston costs more than another
Four different tasks sit behind the four situations above — which is why there's no fair single price. Which of them you're in is chiefly what moves the cost. Two things come after that: the petrol that got in as a share of what the tank holds, then the spot the car is in and whether a van can get to it safely.
What went in, how much, and if it has run — three questions our engineers ask before quoting, not after, for precisely that reason. Those answers are what change a range into one firm number.
About Kingston
Kingston is a suburban area in Greater Manchester, situated on the riverside with an elevation of 97 metres. Kingston lies approximately 6.6 miles from Manchester and is surrounded by nearby places such as Hyde and Flowery Field. Kingston has a population of around 4114 people and predominantly features terraced housing. Kingston is located in the North West region of England, about 157.7 miles from London.
Kingston and Greater Manchester: where our fuel drain cover reaches
Hyde, Flowery Field and The Railway Sidings are among the locations near Kingston that the same vans work, answering petrol in diesel calls across Kingston's SK postcode area. We drain wherever the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it does not have to come to us.
Still at the pump around Kingston?
No position is better: that is where you are. Keep it off. Phone.