How Worried Should You Be? Petrol in a Diesel Car in Elmer
Unstarted? Then less anxious than you likely are. Till your ignition primes your pump, the starter turns, or your car is driven, petrol in a diesel tank simply rests there and does nothing. Which means the truthful reply to the first Elmer question — "have I wrecked it?" — normally no. Keep it that way: leave your engine off then call Petrol in Diesel. Read on for three things: the effect petrol has inside a diesel engine, the clues of how far it has got, and ways to make sure you never do it again.
Inside the motor: what petrol in a diesel really does
Two tasks fall to diesel on its journey through a motor. It burns, and before it combusts it lubricates. What keeps the surfaces inside the high-pressure pump and the fuel injectors from wearing against each other is your diesel flowing through them — they are built to extremely fine gaps.
Of these two tasks, petrol handles the first badly and the second not at all. Being less viscous than diesel, petrol strips out the lubrication a fuel system needs, leaving a pump running on that mixture to wear itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the rattling.
The shape of the trouble is plain when you put those together. Contact doesn't do the damage — movement does. All a tank with petrol in it amounts to is a fuel fault. Once your pump has been running on that petrol, a mechanical fault has begun: whatever is shed by a pump that is wearing is carried downstream to the injectors with your fuel.
Four situations our engineers see in Elmer: how bad is petrol in a diesel?
The best case there can be: filled up, not once started. Being on a forecourt is what makes this possible: elsewhere, the vehicle has been driven there to begin with. With that petrol kept inside that tank alone, it is emptied and flushed on the spot, and nothing more is needed.
A moment's running, or just the ignition on. Petrol has left the tank and got to your filter and the lines, since the system has been bled. Normally nothing more than draining, cleaning and seeing to the fuel filter, so still easy.
Driven a couple of miles. Now the pump has spent these miles running on weakened fuel. Distance is only half of that; how hard it was driven matters equally. Either way this work includes that tank, the lines, your filter and clean fuel through the entire circuit. Short trips, such as the school run to Bishop Tufnell CofE Primary School, Felpham, are one thing. Any miles on the Waterlooville Bypass, under 25 miles from Elmer, means the engine has worked hard throughout, and a run to Chichester, under 10 miles away, makes a very different job too.
Driven on till it complained — knocking, smoke, a ragged idle, a soft throttle. The fuel isn't acting like diesel any more, and your engine is telling you. Stop where you are — on the verge on Templesheen Road, at the kerb, down a side road — and do not move it. A car stopped quickly very rarely has long-term damage, because the fuel drain and the flush, which still come first, sort it out.
What Elmer motorists get told about petrol in a diesel — and the stories in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It will not. Topping up takes out nothing; it gives you a fuller tank of the same mix. That advice assumes a diesel fuel system handles petrol by percentage. It does not.
If anything, the opposite is true. Myth: "A newer diesel can cope with a bit of petrol." A modern diesel runs its fuel through more precise components at higher pressure, which makes the lubrication matter more, not less.
"It starts, it drives, so there is no harm" — the myth that trips up more people than any other. Feed diesel to a petrol engine and it usually will not run, so the motorist stops — and the damage stops with them. Whilst your pump wears, a diesel fed petrol normally starts, ticks over and drives away as though nothing has happened. Running is not the same as fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a separate problem. What petrol has thinned stays weakened, and that petrol stays in your tank anyway.
Once your engine has been run, part of that petrol sits in your filter and the fuel lines, not the tank — and the next start sends it right back through the pump. So the myth "drain that tank yourself and you're sorted" does not hold. Clearing petrol into a can at the roadside is also really dangerous.
How does petrol in a diesel occur?
No one does it on purpose, and it is rarely carelessness. One way only, since of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one mostly won't fit a petrol vehicle. That is how the forecourt makes it straightforward.
When habit and the car stop matching, it happens. Hire cars, courtesy cars, and motors that are new to you. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. Filling up in a rush en route to Littlehampton, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: exactly when it occurs. Throw in rain, a phone call or a back seat full of kids, and your hand repeats what it has always done.
How to prevent petrol in a diesel at your next fill-up around Elmer
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, though most usually do. Read the petrol pump's label; the colour is only a clue.
- Plenty of vehicles state the fuel type inside the filler flap or on the cap, and so check there on the first fill in any vehicle you do not know.
- Label 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 meaning to remember.
- "Diesel", out loud, before you pick up the nozzle — every time a new or hired car needs its first tank. It seems daft. It works.
- Mistakes like this are simple to make whilst your mind is on something else, and so the phone goes away.
- Add-on devices exist for vehicles without one, and some diesels are built with a filler that will not take a petrol nozzle. Useful — but a backstop at best, never a reason to stop checking the label.
- As soon as you realise, stop: less petrol in your tank means a weaker mixture. What to do next doesn't change, though — still do not crank it.
Put petrol in a diesel around Elmer already?
The order of things is brief, then. Starting it is out, and so is turning on your ignition. Still at the forecourt, at Esso or anywhere else? Ask the staff to help you roll the car away from the petrol pump. Next, 0333 366 0103. We will ask what was put in, roughly how much, and if it has been run.
If it was AdBlue rather than petrol, say so. That's a different issue — corrosion and deposits and not lost protection — and it has its own page for Elmer.
What makes one Elmer petrol in a diesel job cost more than the next
Four different jobs lie behind the four situations above — which is why there is no honest single price. Which of them you are in is mostly what moves your cost. Two things follow that: the petrol that got in as a proportion of what your tank takes, then the place the car is in and whether a van can get to it safely.
That's why we ask three queries before quoting rather than after: what was put in, how much, and whether it has run. A range becomes a straight figure when the answers are in.
About Elmer, for a moment
Elmer is a coastal suburban area in West Sussex, situated near the cities of Chichester and Bognor Regis. Elmer lies at a low elevation of around 4 metres, close to the shoreline and adjacent to the nearby settlements of Ancton and Middleton-on-Sea. Elmer has a population of approximately 2010 residents, predominantly living in detached housing. Elmer is also within commuting distance of London, being around 53.6 miles away.
Fuel drain cover across West Sussex, Elmer included
Petrol in diesel call-outs in Elmer — part of the PO postcode area — go to vans that also cover the locations around it, Ancton, Middleton-on-Sea and Atherington included. We drain wherever the vehicle is — your own drive, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
At the petrol pump in Elmer, still?
Then you're in the best place there can be. Leave the vehicle switched off, then ring.