Upper Borth: Petrol in a Diesel Car? How Worried to Be
Likely less than you are now — as long as nobody has started the vehicle. Everyone around Upper Borth starts with "have I ruined it?", and the honest answer is generally no: petrol resting inside your tank of a diesel stays harmless until priming, cranking or driving pulls it into the fuel system. Petrol in Diesel is who to phone, with your motor kept off, so it remains that way. What petrol really does to a diesel, how to judge how far it has travelled, and how to keep it from happening a second time: that's the rest of this page.
What petrol in a diesel does to the motor
Two jobs fall to diesel on its route round a motor. Before it burns, it lubricates — then it burns. Extremely fine tolerances go into the fuel injectors and the high-pressure pump, and only the diesel running through stops their surfaces grinding together.
Of these two jobs, petrol handles the first badly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, so a pump running on the blend wearing itself. It is also made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the knocking.
The shape of the trouble is plain once you put those together. It is circulation that causes the harm, not contact. All a tank with petrol in it amounts to is a fuel problem. Whatever a worn pump sheds goes on, carried by the fuel, into the fuel injectors further along, which is why a pump that has worked on that petrol is where a mechanical fault begins.
Petrol in a diesel in Upper Borth: how bad is it? Four situations
The best case there is: filled up, not once started. Just the tank has petrol in it, so the job is clearing the tank and purging your system where your car stands. This scenario can only truly occur on a forecourt: anywhere else, the car got there by being driven.
The ignition switched on, or a brief start. With the fuel system primed, the lines and filter now contain petrol that has come from the tank. That is usually still a straightforward job — a drain, a flush, and your filter seen to.
Your pump now worked a few miles on diluted fuel — that is what driving the vehicle does. Mileage is only half of it; how hard it was driven matters equally. Either way the work runs to that tank, your lines, the fuel filter and clean fuel through the whole circuit. The school run to the local primary school is one thing. A run as far as Bangor, over 50 miles away, is a very different job. So is any miles on the M4, over 50 miles from Upper Borth, where the engine has been labouring hard throughout.
It protested, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone ragged. The fuel isn't acting like diesel any more, and the engine is saying so. Pull up wherever you are — the verge on B4572, a lay-by, a side street — and leave the car where it is. A car pulled over quickly very seldom has lasting damage, because the drain and the flush, which still come first, deal with it.
Myths Upper Borth 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. Topping up takes out nothing; it gives you a fuller tank of the same mixture. A diesel fuel system does not tolerate petrol by percentage in the way that advice supposes.
Not so: a newer diesel copes with a bit of petrol. If anything, the reverse. Lubrication matters more on modern diesels, not less, since their fuel passes through smaller components at higher pressure.
The myth that catches people off guard: if it starts and drives, it must be unharmed. A petrol engine fed diesel usually will not run, so the driver stops and the damage stops with them. A diesel fed petrol normally starts, idles and drives away as though nothing has happened, while your pump grinds. Being able to run is not the same as being fine.
Myth: "Add some two-stroke oil and drive the car home." It's an outdated workaround for a distinct problem. What petrol has thinned stays thinned, and the petrol remains in that tank regardless.
Myth: "Drain that tank yourself and you're sorted." Once your engine has been run, some of the petrol is no longer in your tank: it's in the fuel filter and the fuel lines, and it goes right back through the pump on your next start. Emptying petrol into a can by the kerbside is also truly risky.
Petrol in a diesel: how does it happen?
On purpose? Never. Through carelessness? Seldom, 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 generally will not go into a petrol vehicle at all. So the mistake runs one way.
It occurs when habit and the car stop matching. Courtesy car, hire car, or a vehicle that's new. A household with one petrol and one diesel on the drive. The pumps in a different order on a familiar forecourt. A rushed fill on the way to Borth with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Tiguan in front of you at the forecourt for its first tank — that is when. The hand repeats what it has always done when you add rain, a phone call or a back seat full of kids.
Next time you fill up in Upper Borth: preventing petrol in a diesel
- Read the petrol pump, not the colour. In the UK unleaded handles are normally green and diesel black, but not on every forecourt. The label is what counts.
- Check your filler flap. Many motors state the fuel type inside the flap or on the cap. Look at it on the first fill in a motor you do not know.
- One of each in the home? Mark the key to your diesel — a coloured fob, a sticker — because intending to remember isn't enough.
- Before the nozzle leaves the pump the first time you fuel a hired or new vehicle, say "diesel" out loud. Silly, perhaps, yet it works.
- Thinking about something else is when this becomes an easy mistake to make, and so put the phone away then keep your mind on the petrol pump.
- Some diesels have a filler built to block a petrol nozzle, and devices you can add exist for motors without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the pump.
- Noticing it mid-fill? Stop there and then. A weaker mix results from less petrol inside your tank, but your next step remains the same: don't crank it.
Already put petrol in a diesel in Upper Borth?
Then, there is only a short order of things. Never fire it up, and don't switch the ignition on. If you are still on the forecourt — the nearest petrol station or anywhere else — ask the attendants to help you roll the vehicle clear of the pump. Then phone 0333 366 0103 and tell us what was put in, roughly how much, and whether it has run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost lubrication, make it a separate fault — Upper Borth has a page all for it.
Upper Borth petrol in a diesel tasks: why one costs more than another
Four different jobs sit behind the four situations above — which is why there's no fair single price. Which of them you're in is chiefly what shifts your cost. Where the car is counts too, and whether our van can safely reach it, after the proportion of petrol to what that tank holds.
That is why we ask three queries before quoting instead of after: what got in, how much, and whether it has run. Those replies change a range into a straight figure.
About Upper Borth and where it is
Upper Borth is a small coastal suburban area in Ceredigion, situated near the villages of Glanwern and Borth. Upper Borth lies at an elevation of 36 metres, overlooking the coastline of Cardigan Bay. Upper Borth is characterised by its predominantly detached housing stock, reflecting its residential nature.
Across Ceredigion and around Upper Borth: fuel drain cover
Upper Borth rests in the SY postcode area, and the teams that answer petrol in diesel calls there work the locations around it as well — Glanwern, Borth and Dol-y-Bont among them. No need to move the car to us. Forecourts, supermarket car parks, lay-bys and your own drive are all spots where we work.
Upper Borth: still at the pump?
The best position there is, then — that is where you are. Call, and leave it switched off.