Petrol in a Diesel Car in Ramslye: How Worried Should You Be?
Not started? Then less worried than you likely feel. Everyone around Ramslye begins with "have I wrecked it?", and the fair answer is normally no: petrol left in the tank of any diesel stays harmless till priming, cranking or driving pulls it into the fuel system. Leave your motor off then ring 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 tell how far it has got, and how to make sure it doesn't happen to you a second time.
Inside the engine: what petrol in a diesel really does
Passing through an engine, diesel is doing two jobs at the same time. It protects to begin with, and only then does it burn. What keeps the surfaces inside your high-pressure pump and the fuel injectors from grinding against one another is your diesel passing through them — they're designed to extremely fine clearances.
Petrol does the first job poorly 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 the blend wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is where you get the rattling.
Put those together and the shape of the issue is clear. Not contact but movement is what does the damage. Where that petrol is only inside your tank, it is an issue of fuel, nothing more. A pump that has been working on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the injectors further on.
How serious is petrol in a diesel? Four scenarios our engineers see around Ramslye
Filled up, and never started: nothing beats it. Being on a forecourt is what makes this possible: elsewhere, your car has been driven there to begin with. With the petrol kept inside that tank alone, it's drained and cleaned right where it stands, and nothing more is needed.
Your ignition switched on, or a short start. Once primed, your system has pulled petrol out of the tank up to the filter and the lines. Drain, flush, deal with the filter: still usually easy.
Those few miles on the road were your pump working on fuel thinned by petrol the whole way. How hard the vehicle was driven matters as much as how far, and this work covers the tank, the lines, the fuel filter and fresh fuel through the whole system. Short trips, like the school run to St Mark's Church of England Primary School, are one thing. Driving as far as Brighton and Hove, under 50 miles away, makes a very different task — as does any miles on the M25, under 15 miles from Ramslye, with the motor running hard all the way.
Knocking, a lumpy idle, smoke, a throttle gone soft: driven until it complained. That's your engine telling you its fuel has stopped acting like diesel. Stop wherever you are — the verge on Saunders Road, a lay-by, a side street — and leave it where it is. The drain and flush still come first, and they deal with it: if a vehicle is stopped quickly, permanent damage is very unusual.
Ramslye drivers and the petrol in a diesel stories they hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. That advice presumes a diesel fuel system handles petrol by percentage. It does not.
Myth: "A newer diesel can cope with a bit of petrol." If anything, the reverse. At higher pressure, through finer components: that's how a modern diesel moves its fuel, and so the lubrication counts more, not less.
The myth that catches drivers out: if it starts and drives, it must be unharmed. Feed diesel to a petrol engine and it generally won't run, and so the motorist stops — and the harm stops with them. Feed petrol to a diesel and it usually fires up, ticks over and pulls away as if nothing happened — all while its pump is wearing. Running does not mean fine.
An old fix for a distinct fault lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has thinned remains weakened, and that petrol remains in your tank regardless.
If your engine has run, part of that petrol is in the fuel filter and the lines, not your tank — and your next start sends it straight back through your pump. So the myth "drain that tank yourself and you're sorted" doesn't stand up. It is also truly dangerous to drain petrol into a can at the roadside.
Petrol in a diesel: how does it take place?
Carelessness is rarely the cause, and no one means to do it. The petrol nozzle is the smaller of the two and slips into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol motor at all. The forecourt makes it simple, and the error runs one way.
When habit and the vehicle stop matching, it takes place. Courtesy car, hire car, or a car that is brand new. Two motors on one drive, one petrol, one diesel. The pumps in a different order on a well-known forecourt. Filling up in a rush on the way to Tunbridge Wells, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a motorist used to petrol: precisely when it occurs. Your hand repeats what it has always done once you add rain, a phone call or a back seat full of kids.
How to avoid petrol in a diesel on your next fill-up in Ramslye
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most generally do. Check the petrol pump's label; the colour is only a clue.
- Check the filler flap. Many cars state the fuel inside the flap or on the cap. Look at it on your first fill in any car you don't know.
- Mark the 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 comes off the petrol pump the first time you fuel a hired or new motor, say "diesel" aloud. Daft, perhaps, but it does the trick.
- Tuck your phone away. This is an easy mistake to make whilst you're 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. Useful — but a backstop at best, never a reason to stop checking the label.
- Stop the moment you notice. Less petrol in that tank means a weaker mix. It does not change what to do next, which is still not to fire it up.
Ramslye: already put petrol in a diesel?
The order of things is short, then. Do not fire it up, and do not turn the ignition on. If you are still at the forecourt — Sainsbury's or anywhere else — ask the staff to help you roll the car away from the petrol pump. Call 0333 366 0103 next, with three answers — your fuel, the approximate quantity, and if it's run.
If it was AdBlue and not petrol, say so. That's a different fault — corrosion and deposits rather than lost protection — and it has its own page for Ramslye.
One petrol in a diesel task in Ramslye costs more than another. Why?
The four situations above are four separate jobs, so no single quote for this would be fair. What shifts the cost is chiefly which of them you are in. Where the car is counts too, and whether a van can safely get to it, after the proportion of petrol to what the tank holds.
What got in, how much, and if it has run — three queries our engineers ask before quoting, not after, for precisely that reason. Those answers turn a range into a straight figure.
About Ramslye
Ramslye is a suburban area situated on the riverside in Kent, with an elevation of 88 metres. Ramslye lies within commuting distance of London, approximately 31 miles away, and is also close to the city of Brighton and Hove. Ramslye is surrounded by nearby places such as Hungershall Park, Broadwater Down, and Nevill Park, and is characterized by predominantly flat housing. Ramslye has a population of around 3558 residents.
Across Kent and in Ramslye: fuel drain cover
Hungershall Park, Broadwater Down and Nevill Park are among the spots near Ramslye that the same vans work, answering petrol in diesel calls across Ramslye's TN postcode area. Our technicians drain where the vehicle is — your own driveway, a lay-by, a supermarket car park, a forecourt — so it never needs to come to us.
Ramslye: still at the petrol pump?
In that case, you couldn't be in a better spot. Keep it off. Ring.