Northfield: Petrol in a Diesel Car? How Worried to Be
Less than you probably are, if it hasn't been started. Petrol resting in a diesel tank does nothing to your motor till something draws it through the system — your ignition priming your pump, your starter, or the drive itself. So the fair answer to the first query everyone in Northfield asks, "have I ruined it?", is normally no. Petrol in Diesel is who to call, with your engine kept off, so it remains that way. Read on for three things: the effect petrol has inside a diesel engine, the clues of how far it has got, and the way to make sure you never repeat it.
What petrol in a diesel does to the motor
Two tasks fall to diesel on its journey round a motor. Lubricating comes before burning; it does both. Built to very fine tolerances, your injectors and your pump rely on the diesel flowing through them to keep their surfaces from wearing against one another.
Petrol handles the first task badly and the second not at all. Being less viscous than diesel, petrol strips out the protection a fuel system needs, leaving a pump running on that mixture wearing itself. It is also made to resist igniting under compression — the opposite of what a diesel needs — which is why you get the knocking.
Put those together and the shape of the trouble is clear. The harm is done by movement, not by contact. All a tank with petrol in it amounts to is a fuel fault. Whatever a worn pump sheds travels on, borne by the fuel, into your injectors further along, which is why a pump that has been working on the petrol is where a mechanical issue begins.
Four scenarios our engineers see around Northfield: how bad is petrol in a diesel?
The best case there can be: filled up, not once started. On a forecourt, and truly only there, the petrol is still limited to the tank — since anywhere else the vehicle was driven to get to it. The job is draining and purging on the spot.
Started for a second, or just the ignition on. With the fuel system primed, the lines and filter already hold petrol that came from the tank. That's usually still a simple task — a drain, a flush, and the fuel filter seen to.
A couple of miles driven, and the pump has spent every one of them working on thinned fuel. Mileage is only half of it; how hard it was driven matters equally. Either way this work runs to that tank, the lines, the filter and clean fuel through the entire system. Driving the children to the local primary school is one kind of trip. Very different a second time: a trip to Glasgow, under 15 miles away, or any miles on the M80, under 5 miles from Northfield, where your engine kept running hard.
Clattering, an uneven idle, smoke, a throttle gone soft: driven until it complained. That's the engine telling you its fuel no longer is behaving like diesel. Whether it's the verge on Rennie Road, a lay-by or a side street, stop where you are then leave it. What goes first is still the drain and flush-through, and that sorts it out, with permanent damage very rare if a car is stopped early.
Stories Northfield drivers hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It will not. Nothing is removed by topping up — you are left with a bigger tank, still the same mixture. A diesel fuel system does not accept petrol by percentage in the way that guidance assumes.
Myth: "A current diesel can cope with a bit of petrol." If anything, the reverse. Smaller parts and higher pressure are how a modern diesel runs its fuel, and that makes the protection matter more, not less.
This is the one that fools motorists. Myth: "If it starts and drives, there is no damage done." Feed diesel to a petrol motor and it generally won't run, and so the motorist stops — and the harm stops with them. A diesel fed petrol usually starts, ticks over and drives away as though nothing has happened, whilst your pump wears. Being able to run is not the same as being fine.
An outdated workaround for a distinct fault lies behind this one. Myth: "Add some two-stroke oil and drive it home." It does not put back what petrol has diluted, and that petrol is still in the tank after that.
"Drain it yourself and you are sorted" — a myth, because after it's been running some petrol lies in the filter and lines, ready to go straight back through the pump at your next start. It is also truly dangerous to drain petrol into a can at the kerbside.
How petrol ends up: petrol in a diesel
It's seldom carelessness, and no one does it on purpose. The petrol nozzle is the slimmer 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 simple, and the slip runs one way.
When routine and the vehicle stop matching, it occurs. A new car, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. A forecourt you know, but with its pumps laid out differently. Fuelling up in a hurry on the way to Croy, with a train to catch. A new-to-you diesel Volkswagen Golf, its first fuelling, and a driver used to petrol: exactly when it happens. Throw in a back seat full of children, a phone call or rain, and the hand wins.
Preventing petrol in a diesel next time you fill up in Northfield
- The label is what matters, and so check the petrol pump rather than the colour: in the UK unleaded handles are normally green and diesel black, but not on each forecourt.
- In a motor you do not know, look inside the flap over the filler or at the cap before the first fill: plenty of vehicles state the fuel type there.
- A coloured fob or a sticker on the diesel's key achieves more than any amount of meaning to remember, for a home with one of each.
- It sounds daft and it does the trick: on your first fill in a new or hired car, say "diesel" aloud before you take the nozzle off the pump.
- Put the phone away. This is an easy mistake to make whilst you're thinking about something else.
- Add-on devices exist for cars without one, and some diesels are built with a filler that will not accept a petrol nozzle. Useful — but a backstop only, never a reason to stop checking the label.
- Stop the moment you realise. Less petrol inside that tank means a weaker mixture. It does not change what to do next, which is still not to start the vehicle.
Northfield: already put petrol in a diesel?
Then, there is only a short order of things. Do not turn the ignition on, and don't fire it up. If you are still on the forecourt — Shell or anywhere else — ask the staff to help you roll the vehicle away from the petrol pump. Then phone 0333 366 0103 and tell us what was put in, about how much, and if it's run.
Corrosion and deposits form the problem with AdBlue, where petrol means lost lubrication. So if it was AdBlue, say so — and read its own Northfield page.
Why one petrol in a diesel task in Northfield costs more than another
An honest single quote doesn't exist here: four scenarios, four separate jobs. The situation itself does most of the work of moving your cost. Two things follow that: the petrol that was put in as a share of what your tank holds, then the place the car is in and whether our van can get to it safely.
Ahead of any quote, not after, come three questions: your fuel that got in, the quantity, and if it's run. That is why. A range becomes a straight figure once those answers are in.
About Northfield
Northfield is a suburban area situated on the riverside in North Lanarkshire, with an elevation of 114 metres and a mix of terraced housing. Northfield lies approximately 10 miles east of Glasgow, near the communities of Westfield, High Balmalloch, and Balmalloch. Northfield is home to around 2434 residents and forms part of the wider Glasgow urban area. Northfield's location near the river provides scenic views and a distinctive setting.
Fuel drain cover in Northfield and across North Lanarkshire
Westfield, High Balmalloch and Balmalloch are among the locations around Northfield that the same vans work, answering petrol in diesel call-outs across Northfield's G postcode area. No need to bring your car to us. Forecourts, supermarket car parks, lay-bys and your own driveway are all places where we work.
Still at the petrol pump in Northfield?
Then, you couldn't be in a better spot. Phone, and leave it switched off.