Brianside: Petrol in a Diesel Car? How Worried to Be
Far less than you probably are, provided it has not been started. Petrol resting in a diesel tank does nothing to the motor till something draws it through your fuel system — the ignition priming your pump, the starter, or driving itself. So the fair answer to the first question anyone around Brianside asks, "have I ruined it?", is normally no. Leave the engine off and ring Petrol in Diesel — that is how you keep it that way. What petrol really does to a diesel, how to judge how far it's travelled, and how to stop it from happening again: that's the rest of this page.
What petrol in a diesel does to your engine
Two jobs fall to diesel on its route round a motor. Before it burns, it lubricates — then it ignites. What stops the surfaces inside your high-pressure pump and the fuel injectors from wearing against each other is the diesel flowing through them — they're designed to extremely fine clearances.
Of these two jobs, petrol handles the first badly and the second never. A pump running on a petrol mix is wearing itself out, because petrol is runnier than diesel and takes away the protection your fuel system depends on. Petrol is also made to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that is where the rattling starts.
Put these together and the shape of the problem is plain. Not contact but movement is what causes the harm. Petrol in a tank is a fuel issue. Whatever a worn pump sheds goes on, borne by the fuel, into the fuel injectors downstream, which is why a pump that has been working on the petrol is where a mechanical fault begins.
Four scenarios our technicians see in Brianside: how serious is petrol in a diesel?
Fuelled, and never started: no case is better. Being at a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With the petrol held in the tank alone, it is cleared and cleaned right where it stands, and nothing more is needed.
Ignition on, or started for a second. The fuel system has been bled, and so petrol has left that tank and reached your filter and your lines. That is normally still a simple job — a drain, a flush, and your filter seen to.
Those few miles on the road meant your pump working on fuel diluted by petrol the whole way. How hard your car was driven counts as much as how far, and this work takes in that tank, the lines, the fuel filter and fresh fuel through the whole system. Driving the kids to Parklands Primary School is one kind of trip. Driving as far as Leeds, under 5 miles away, makes a very different task — as does any miles on the M1, under 3 miles from Brianside, with the motor working hard the whole time.
It complained, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone uneven. The engine is telling you your fuel is no longer acting like diesel. Leave it wherever it stops: a lay-by, a side street, the verge on Inglewood Place. Long-term damage is very unusual when a vehicle is pulled over early, and the drain and flush that still come first sort it out.
What Brianside drivers get told about petrol in a diesel — and the myths in it
"Top it up the rest of the way with diesel and it'll be fine" — a myth. It won't. Topping up removes nothing; it gives you a fuller tank of the same mixture. The assumption behind that guidance — that diesel fuel systems accept petrol by percentage — is wrong.
"Newer diesels can handle a little petrol" — a myth, and closer to the opposite. A current diesel sends its fuel through finer components at higher pressure, which makes the lubrication matter more, not less.
This is the one that catches motorists. Myth: "If it starts and drives, there's no damage done." Feed diesel to a petrol engine and it normally will not run, and so the motorist stops — and the damage stops with them. Nothing seems to have happened when a diesel fed petrol fires up, ticks over and drives away, as it usually will; meanwhile the pump grinds. Being able to run isn't the same as being fine.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct problem. The petrol is still inside your tank afterwards, and what it has thinned isn't put back.
"Drain it yourself and you're sorted" — a myth, since after it has been running some petrol sits in the filter and lines, ready to go straight back through your pump on the next start. On top of that, petrol drained into a can by the road is truly hazardous.
How petrol ends up: petrol in a diesel
A careless moment is seldom the cause, and nobody means to do it. One way only, since of the nozzles: the narrower petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one generally won't fit a petrol car. That's how the forecourt makes it easy.
Routine and your car falling out of step is when it occurs. A new vehicle, a hire car or a courtesy car. A household with one petrol and one diesel on the drive. A well-known forecourt with the pumps in a different order. A hurried fill en route to Cross Gates with a train to catch. Years of petrol motors behind you, a diesel Renault Megane in front of you at the forecourt for its first tank — that's when. With rain, a call arriving, or a car full of children to deal with, the hand simply does what it has always done.
Brianside drivers: how to prevent petrol in a diesel next time
- Green for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Go by the label on the pump, not the colour.
- Plenty of vehicles state the fuel type inside your filler flap or on the cap, so check there on the first fill in a car you don't know.
- One of each in the house? Mark the key to your diesel — a bright fob, a sticker — because meaning to remember isn't enough.
- Say it before you lift it. On your 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.
- Whilst you're thinking about something else, this is an easy mistake to make — so tuck the phone away.
- Some diesels come with a filler built to reject a petrol nozzle, and devices you can add are available for cars without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop checking the pump.
- Stop as soon as you notice. Less petrol in your tank makes a weaker mixture. It does not change what to do next, which is still not to fire it up.
Brianside: already put petrol in a diesel?
Short and simple, then, is the order of things. Don't fire it up, and do not switch the ignition on. Yet at the forecourt, at Shell or anywhere else? Ask the staff to help you push the car clear of the pump. Then phone 0333 366 0103 and tell us what went in, about how much, and if it's run.
If it was AdBlue rather than petrol, say so. That is a separate problem — corrosion and deposits rather than lost lubrication — and it has its own page for Brianside.
One petrol in a diesel job in Brianside costs more than another. Why?
The four scenarios above are four separate tasks, so no single quote for this would be honest. What moves the cost is chiefly which of them you're in. The proportion counts next, meaning how much of that tank is petrol, followed by the position of your car and whether getting to it is safe for our van.
Before any quote, not after, come three queries: your fuel that was put in, its volume, and whether it has run. That is why. Those replies are what turn a range into one firm number.
About Brianside
Brianside is a suburban area located near Leeds in West Yorkshire, sitting at an elevation of 84 metres in the inland landscape of the county. Brianside is characterized by its semi-detached housing stock and is situated close to nearby places such as Cross Gates and The Oval. Brianside is a relatively small community, with a population of approximately 6239 residents, and is within easy reach of Leeds city centre, being just 3.8 miles away.
Across West Yorkshire and in Brianside: fuel drain cover
Brianside rests in the LS postcode area, and our vans that answer petrol in diesel call-outs there work the locations near it as well — Cross Gates, The Oval and The Green among them. You need not bring the car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places we drain.
Still at the petrol pump in Brianside?
Nothing beats it: that's where you are. Switched off it stays; then call.