How Worried Should You Be? Petrol in a Diesel Car in Nettlesworth
Likely less than you already are — provided no one has started the car. Everyone around Nettlesworth begins with "have I ruined it?", and the fair answer is usually no: petrol left in that tank of a diesel remains harmless until priming, cranking or driving draws it into your fuel system. Petrol in Diesel is who to phone, with your motor left off, and so it stays that way. Keep reading for three things: the effect petrol has inside a diesel engine, the clues of how far it has spread, and the way to make sure you don't repeat it.
Petrol in a diesel: what does it do to your engine?
Passing through a motor, diesel is doing two things at the same time. It burns, and before it ignites it lubricates. Built to very fine gaps, the injectors and the pump depend on the diesel moving through them to stop their surfaces wearing against one another.
Of these two jobs, petrol manages the first poorly and the second never. It's thinner than diesel and removes the protection the fuel system rests on, so a pump running on a petrol mixture is a pump wearing itself. And petrol is designed to resist igniting under compression, which is the opposite of what a diesel needs from its fuel. That's where the clattering comes from.
Together, those make the shape of the trouble plain. The damage is done by movement, not by contact. Where the petrol is only inside the tank, it's a problem 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 your injectors downstream.
Petrol in a diesel in Nettlesworth: how serious is it? Four cases
The best case there is: filled up, not once started. That petrol is in that tank and only that tank, and the task is a drain and a flush where the car stands. This is the one situation that can only truly occur at a forecourt, because anywhere else the vehicle has been driven to get there.
A brief spell of running, or just the ignition on. Petrol has come out of the tank and got to the fuel filter and the fuel lines, since the fuel system has been bled. Still usually straightforward: drain, flush, and your filter dealt with.
The pump now worked a few miles on diluted fuel — that is what driving the car meant. How hard the vehicle was driven matters as much as how far, and this work covers the tank, the fuel lines, your filter and fresh fuel through the whole circuit. On the school run to Nettlesworth Primary School, the miles is small. Getting as far as Durham, under 5 miles away, makes a very different task — as does any distance on the A1(M), under 5 miles from Nettlesworth, with your engine running hard all the way.
It protested, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone uneven. The motor is telling you your fuel is no longer behaving like diesel. Stop wherever you are — the verge on Park View, a lay-by, a side street — then leave it where it is. What goes first is still the fuel drain and flush-through, and that sorts it out, with permanent damage very rare if a car is stopped soon.
Nettlesworth people 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 are left with a bigger tank, still the same mixture. The idea behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
Myth: "A modern diesel can cope with a bit of petrol." If anything, the opposite. A current diesel runs its fuel through smaller parts at higher pressure, which makes the protection count more, not less.
The myth that catches motorists off guard: if it starts and drives, it must be unharmed. The driver of a petrol motor fed diesel normally stops, since it will not run, and the damage stops with them. Feed petrol to a diesel and it usually fires up, idles and drives away as if nothing has happened — all while its pump wears. Fine and running are not the same thing.
An outdated fix for a different problem lies behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has weakened stays thinned, and that petrol remains inside that tank regardless.
"Drain it yourself and you're sorted" — a myth, since after it's been running some petrol lies in the fuel filter and lines, waiting to go straight back through your pump at your next start. Also, a can of petrol drained by the roadside is genuinely dangerous.
Petrol in a diesel: how does it occur?
On purpose? Never. Through carelessness? Rarely, if ever. The forecourt makes it easy: the petrol nozzle is the narrower of the two, and it slips into a diesel filler with almost no resistance, whilst a diesel nozzle mostly won't go into a petrol car at all. So the mistake runs one way.
It happens when routine and your car stop matching. Any car that's new to you — hired, on loan as a courtesy car, or just bought. Two cars on one driveway, one petrol, one diesel. Your usual forecourt, its pumps suddenly in a different order. A train to catch, and a rushed fill on the way to Chester-Le-Street. Years of petrol vehicles behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that's when. With rain, a call coming in, or a car full of children to deal with, your hand just does what it has always done.
Next time you fill up around Nettlesworth: avoiding petrol in a diesel
- Green for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Trust the label on the pump, not the colour.
- In a car you don't know, look inside the flap over the filler or at the cap before the first fill: plenty of vehicles print the fuel type there.
- 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 intending to remember.
- "Diesel", out loud, before you pick up the nozzle — each time a new or hired car needs its first tank. It sounds silly. It does the trick.
- Tuck the phone away. This is an easy mistake to make while you're thinking about something else.
- 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 pump.
- Noticing it halfway? Stop at once. A thinner mix results from less petrol inside your tank, but the next step remains the same: do not crank it.
Already put petrol in a diesel around Nettlesworth?
The order of things is short, then. Never crank it, and don't switch the ignition on. If you're still on the forecourt — Plawsworth Service Station or anywhere else — ask the staff to help you push the car clear of the petrol pump. What went in, roughly how much, and if it's run: tell us those when you call 0333 366 0103.
Say so if it was AdBlue rather than petrol: it is a separate issue, with its own page for Nettlesworth, since AdBlue brings corrosion and deposits rather than lost protection.
What makes one Nettlesworth petrol in a diesel job cost more than the next
Four separate tasks sit behind the four scenarios above — which is why there is no fair single price. The scenario itself does most of the work of moving the cost. Two things follow that: the petrol that was put in as a proportion of what that tank takes, then the spot the car is in and whether a technician can reach it safely.
Before any quote, not after, come three questions: the fuel that went in, the quantity, and whether it's run. That is why. A range becomes a straight figure when those answers are in.
About Nettlesworth
Nettlesworth is a small village in County Durham, situated approximately 3.3 miles from the city of Durham. Nettlesworth sits inland at an elevation of around 100 metres, near the Tan Hills and close to neighbouring villages such as Plawsworth and Kimblesworth. Nettlesworth has a population of around 610 people, predominantly living in semi-detached housing.
Fuel drain cover across Durham, Nettlesworth included
Our teams answering petrol in diesel calls around Nettlesworth, in the DH postcode area, also work the locations around it, Tan Hills, Plawsworth and Kimblesworth included. The vehicle doesn't need to come to us: our engineers drain at a forecourt, in a supermarket car park, in a lay-by or on your own driveway.
Still at the petrol pump in Nettlesworth?
In that case, you couldn't be in a better spot. Keep it off. Call.