How Worried Should You Be? Petrol in a Diesel Car in Johnshaven
Probably less than you already are — provided nobody has started it. Petrol resting in a diesel tank does nothing to the motor till something draws it through the fuel system — your ignition priming the pump, your starter, or driving itself. So the fair answer to the first query everyone around Johnshaven asks, "have I ruined it?", is generally no. Keep it that way: leave the motor off and call Petrol in Diesel. 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 a second time.
Inside your engine: what petrol in a diesel really does
Diesel has two tasks on its way through a motor. It combusts, and before it combusts it lubricates. Made to very fine clearances, the injectors and the pump depend on your diesel moving through them to keep their surfaces from wearing against one another.
Petrol handles the first job poorly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump running on that mixture to wear itself. It's also made to resist igniting under compression — the opposite of what a diesel needs — which is where you get the knocking.
The shape of the issue is clear once you put those together. It is circulation that does the damage, not contact. All a tank with petrol in it amounts to is a fuel issue. After your pump has been running on that petrol, a mechanical issue has begun: anything shed by a pump that is grinding travels onward to the injectors with the fuel.
How bad is petrol in a diesel? Four scenarios we see around Johnshaven
Fuelled, and not started: nothing beats it. That petrol is inside the tank and just your tank, and the task is a drain and a flush where the car sits. This is the one situation that can only really happen at a forecourt, since anywhere else your car has been driven to get there.
A brief spell of running, or merely the ignition on. With the fuel system primed, your lines and filter already contain petrol that has come from that tank. Drain, flush, deal with your filter: still usually simple.
Those few miles driven meant the pump labouring on fuel weakened by petrol the whole way. Miles is only half of it; how hard it was driven counts equally. Either way the work includes that tank, the fuel lines, your filter and fresh fuel through the whole circuit. On the school run to the local primary school, the mileage is small. Very different again: a trip to Aberdeen, under 50 miles away, or any distance on the M90, under 50 miles from Johnshaven, where the motor never stopped working hard.
Driven till it protested. Rattling, an uneven idle, smoke, a throttle that has gone soft. The engine is telling you the fuel is no longer acting like diesel. Whether it's the verge on Anchor Lane, a lay-by or a side road, stop there and leave it. What goes first is still the drain and flush-through, and that takes care of it, with permanent damage very rare if a car is stopped quickly.
Johnshaven drivers and the petrol in a diesel myths they hear
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. That advice assumes a diesel fuel system handles petrol by percentage. It doesn't.
"Newer diesels can handle a little petrol" — a myth, and nearer the reverse. At higher pressure, through smaller components: that is how a modern diesel handles its fuel, and so the protection counts for more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that fools drivers. Feed diesel to a petrol engine and it normally won't run, and so the driver stops — and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump grinds. Being able to run is not the same as being fine.
Myth: "Add some two-stroke oil and drive it home." It's an outdated workaround for a separate problem. What petrol has diluted stays diluted, and that petrol stays in the tank anyway.
The next start sends petrol back round your pump from the fuel lines and the filter, where some of it sits after the engine has run. That is why draining your tank yourself does not leave you sorted — a myth. And, a can of petrol drained by the roadside is genuinely risky.
Why petrol in a diesel occurs at all
It's rarely carelessness, and no one does it on purpose. A diesel nozzle generally won't fit a petrol car, but the smaller petrol nozzle goes into the filler of a diesel almost without resistance — so forecourts make this one mistake simple, and only in that direction.
When habit and the vehicle stop matching, it takes place. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. Your normal forecourt, its pumps suddenly in a different order. A train to catch, and a rushed fill en route to Laurencekirk. Exactly the moment it takes place: after years of driving petrol, someone fills a diesel Renault Megane for the first time. With rain, a call coming in, or a car full of children to deal with, the hand just does what it has always done.
Johnshaven people: how to avoid petrol in a diesel next time
- A green handle for unleaded and black for diesel is normal in the UK — yet not on each forecourt. Trust the label on the petrol pump, not the colour.
- Check your filler flap. Plenty of vehicles state the fuel inside the flap or on the cap. Look at it on your first fill in any vehicle you do not know.
- Good intentions count for less than a sticker or a fob in a vivid colour on your diesel's key if a household has one of each. So label it.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump. It sounds daft and it does the trick.
- 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 reject a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a safety net, not a reason to stop reading the pump.
- Noticing it halfway? Stop there and then. A weaker mixture follows from less petrol in your tank, yet the next stage remains the same: don't start the vehicle.
Put petrol in a diesel around Johnshaven already?
Short and simple, then, is the order of things. Starting it is out, and so is turning on the ignition. Yet on the forecourt, at the nearest petrol station or anywhere else? Ask the attendants to help you push the vehicle away from the petrol pump. Ring 0333 366 0103 next, with three facts — the fuel, the approximate volume, and if it's run.
Say so if it was AdBlue rather than petrol: it's a separate problem, with its own page for Johnshaven, because AdBlue brings corrosion and deposits rather than lost lubrication.
What makes one Johnshaven petrol in a diesel task cost more than the next
The four situations above are four separate tasks, so no single price for this would be fair. The scenario itself does most of the work of moving your cost. Beyond that it is the proportion — how much petrol got in against how much that tank takes — and then where your car is and whether a van can reach it safely.
What went in, how much, and whether it has run — three queries our engineers ask before quoting, not after, for exactly that reason. A range turns into a straight figure once the replies are in.
About Johnshaven
Johnshaven is a small coastal village in Aberdeenshire, situated near the mouths of the Bervie and Cowie burns. Johnshaven sits at a low elevation of around 11 metres, looking out to the North Sea. Johnshaven is part of a network of small communities along this coastline, including nearby Benholm and Gourdon.
Fuel drain cover in Johnshaven and across Aberdeenshire
Johnshaven rests in the DD postcode area, and the vans that answer petrol in diesel calls there work the places near it as well — Benholm, Bush and Gourdon among them. The car does not need to move to us: our engineers drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Johnshaven: still at the petrol pump?
The best position there is, then — that is where you are. Call, and keep it switched off.