Petrol in a Diesel Car in Bare: How Worried Should You Be?
Not started? Then less anxious than you likely are. Everyone in Bare begins with "have I ruined it?", and the honest answer is usually no: petrol resting in the tank of a diesel stays harmless until priming, cranking or driving pulls it into your fuel system. Keep it like that: leave the engine off then ring Petrol in Diesel. The remainder of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you a second time.
Petrol in a diesel: what does it do to the engine?
Two jobs fall to diesel on its journey round a motor. It protects first, and after that does it burn. What keeps the surfaces inside the high-pressure pump and the injectors from grinding against one another is your diesel passing through them — they are designed to extremely fine clearances.
The second job petrol doesn't do at all, and the first it does poorly. It's runnier than diesel and takes away the lubrication your fuel system hinges on, and so a pump running on a petrol mix is a pump wearing itself. And petrol is made to resist igniting under compression, which is the reverse of what a diesel needs from its fuel. That's where the rattling comes from.
Seen together, they show the shape the trouble has. It is movement that causes the harm, not contact. All a tank with petrol in it amounts to is a fuel fault. Once your pump has been working on that petrol, a mechanical problem has begun: anything shed by a pump that is wearing travels onward to your injectors with the fuel.
Four scenarios our engineers see around Bare: how bad is petrol in a diesel?
The best case there is: filled up, never started. Just that tank has petrol in it, and so the job is draining that tank and cleaning your system where the car stands. This situation can only truly happen at a forecourt: anywhere else, your car got there by being driven.
Your ignition turned on, or a short start. The system has been bled, so petrol has left that tank and got to the filter and the fuel lines. Drain, flush, deal with your filter: still usually simple.
Driven a couple of miles. Now the pump has spent these miles working on thinned fuel. Tank, lines, filter, then fresh fuel put through the entire circuit: that's the work, and the way the vehicle was driven counts as much as the miles. Short trips, such as the school run to Great Wood Primary School, are one thing. Any miles on the Lune Valley Interchange, under 3 miles from Bare, means the motor working hard throughout, and a run to Lancaster, under 3 miles away, makes a very different task as well.
Driven till it protested. Clattering, an uneven idle, smoke, a throttle that has gone soft. The fuel isn't acting like diesel any more, and your engine is telling you. Leave it where it stops: a lay-by, a quiet street, the verge on Victor Avenue. A vehicle pulled over soon very seldom has long-term damage, because the drain and the flush, which still go first, sort it out.
Petrol in a diesel stories Bare drivers hear
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing comes out when you top up — that tank simply holds more of the same blend. Percentage is not how a diesel fuel system tolerates petrol, however much that advice assumes.
If anything, the opposite holds. Myth: "A modern diesel can cope with a bit of petrol." Finer parts and higher pressure are the way a newer diesel runs its fuel, and that makes the lubrication count more, not less.
"It starts, it drives, and so no harm done" — the myth that trips up more people than any other. Diesel in a petrol motor usually leaves a motor that won't run: the motorist stops, and so does the harm. Whilst the pump grinds, a diesel fed petrol usually starts, idles and drives away as if nothing has happened. A running engine does not mean fine.
An outdated fix for a separate fault is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." That petrol is still in your tank afterwards, and what it has weakened is not put back.
Once the engine has run, part of that petrol is in the fuel filter and the fuel lines, not your tank — and the next start pulls it right back through your pump. So the myth "drain the tank yourself and you are sorted" does not stand up. And, a can of petrol drained by the roadside is genuinely dangerous.
Why petrol in a diesel occurs at all
It's seldom 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 will not go into a petrol motor at all. The forecourt makes it easy, and the mistake runs one way.
When routine and the car stop matching, it occurs. Any vehicle that's new to you — a hire car, on loan as a courtesy car, or brand new. Households running one of each, petrol and diesel. The pumps in a different order on a well-known forecourt. A rushed fill on the way to Bare Lane with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. With rain, a call coming in, or a car full of children to deal with, your hand simply does what it always has.
Bare drivers: how to prevent petrol in a diesel next time
- The label is what counts, so read the petrol pump instead of the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- The first fill in an unfamiliar car is the time to check your filler flap — on it, or on the cap, many cars state the fuel to use.
- One of each in the household? Mark your key to the diesel — a bright fob, a sticker — because intending to remember is not enough.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car needs its first tank. It seems silly. It works.
- Whilst you are thinking about something else, this is an easy mistake to make — so put your phone away.
- Some diesels have a filler built to block a petrol nozzle, and devices you can add exist for cars without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the petrol pump.
- Stop as soon as you realise. Less petrol in that tank makes a weaker blend. It does not change what to do next, which is still not to crank it.
Put petrol in a diesel in Bare already?
The order of things is short, then. Don't turn the ignition on, and do not start it. If you're still at the forecourt — Sainsbury's or anywhere else — ask the staff to help you roll the car away from the pump. Call 0333 366 0103 next, with three facts — your fuel, the approximate amount, and whether it's run.
If it was AdBlue rather than petrol, say so. That's a separate problem — corrosion and deposits instead of lost lubrication — and it has its own page for Bare.
Why one petrol in a diesel job around Bare costs more than another
A fair single quote does not exist here: four situations, four separate jobs. Which of them you are in is mostly what moves your cost. Two things come after that: the petrol that got in as a proportion of what your tank takes, then the place the car is in and whether a technician can get to it safely.
Before any quote, not after, we ask three questions: your fuel that got in, its amount, and if it has run. That is why. Their answers are what change a range into one firm number.
About Bare itself
Bare is a coastal suburban area in Lancashire, situated near the city of Lancaster and close to the nearby places of Torrisholme, Morecambe, and White Lund. Bare sits at a low elevation of around 7 metres, reflecting its coastal setting. Bare is characterised by its predominantly semi-detached housing stock, which is typical of many suburban areas in the North West of England.
Fuel drain cover around Bare and across Lancashire
Petrol in diesel call-outs around Bare — part of the LA postcode area — go to vans that also cover the locations about it, Torrisholme, Morecambe and White Lund among them. No need to move your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all locations we drain.
Still at the pump around Bare?
Then you're in the best place there can be. Call, and leave it turned off.