Waun-Gron: Petrol in a Diesel Car? How Worried to Be
Unstarted? Then less anxious than you likely feel. Petrol resting in a diesel tank does nothing to your motor till something pulls it through the system — your ignition priming your pump, the starter, or driving itself. So the honest answer to the first query everyone in Waun-Gron asks, "have I ruined it?", is generally no. To keep it that way, ring Petrol in Diesel then leave your motor alone. Keep reading 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.
The motor and petrol in a diesel: what goes on
Passing through a motor, diesel is doing two jobs at once. It lubricates to begin with, and only then does it burn. The high-pressure pump and the fuel injectors are designed to very fine clearances, and your diesel passing through them is what keeps those surfaces from wearing against each other.
Badly at the first, not at all at the second: that's petrol. Being less viscous than diesel, petrol strips out the protection a fuel system needs, so a pump on the mixture wearing itself. It's equally made to resist igniting under compression — the reverse of what a diesel needs — which is where you get the knocking.
Seen together, they make clear what shape the issue takes. The harm is done by movement, not by contact. All a tank with petrol in it amounts to is a fuel fault. A pump that has been running on that petrol is the beginning of a mechanical one, and whatever a worn pump sheds moves on with your fuel to the fuel injectors downstream.
How bad is petrol in a diesel? Four scenarios our engineers see in Waun-Gron
The best case there is: filled up, never started. At a forecourt, and really only there, the petrol is still limited to that tank — because everywhere else the vehicle was driven to get to it. The job is draining and flushing on the spot.
Started for a moment, or just your ignition on. Your system has been bled, so petrol has left the tank and reached the fuel filter and your lines. Drain, flush, deal with your filter: still normally simple.
The pump now worked a few miles on diluted fuel — that's what driving it does. The work is the tank, the fuel lines, the filter and clean fuel through the whole system, and how hard the vehicle was driven matters as much as how far. Short trips, such as the school run to the local primary school, are one thing. Driving as far as Swansea, under 3 miles away, makes a very different task — as does any mileage on the M4, under 3 miles from Waun-Gron, with your engine working hard the whole time.
It complained, and only then stopped: smoke, clattering, a throttle gone soft, an idle gone lumpy. That is your motor telling you its fuel no longer is behaving like diesel. Stop wherever you are — the verge on Penlan Road, a lay-by, a side street — and leave it there. What comes first is still the fuel drain and flush-through, and that sorts it out, with long-term damage very rare when a car is pulled over soon.
What Waun-Gron motorists get told about petrol in a diesel — and the myths in it
False: topping up to full with diesel makes it fine. It doesn't. Nothing is removed by topping up — you are left with a bigger tank, still the same mix. The assumption behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
Not so: a modern diesel copes with a bit of petrol. Rather, the opposite. At higher pressure, through smaller components: that is how a modern diesel handles its fuel, and so the protection counts more, not less.
Myth: "If it starts and drives, there's no damage done." This is the one that fools drivers. The motorist of a petrol motor fed diesel normally has no choice but to stop, since it will not run, and the damage stops there. Feed petrol to a diesel and it normally fires up, idles and pulls away as if nothing has happened — all while its pump wears. Being able to run isn't proof of being fine.
An outdated fix for a different fault is behind this one. Myth: "Add some two-stroke oil and drive it home." That petrol is still inside that tank afterwards, and whatever it has diluted 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, waiting to go right back through the pump at your next start. It's also really dangerous to drain petrol into a can at the kerbside.
Why petrol in a diesel occurs so easily
It's rarely carelessness, and nobody does it on purpose. The petrol nozzle is the narrower of the two and slides into a diesel filler with almost no resistance; a diesel nozzle mostly won't go into a petrol motor at all. The forecourt makes it simple, and the error runs one way.
When routine and your car stop matching, it takes place. Hire cars, courtesy cars, and cars that are new to you. A household with one petrol and one diesel on the drive. Your normal forecourt, its pumps suddenly in a different order. Fuelling up in a hurry on the way to Swansea, with a train to catch. Years of petrol vehicles behind you, a diesel Renault Megane in front of you at 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.
How to avoid petrol in a diesel on your next fill-up around Waun-Gron
- The label is what matters, and so read the petrol pump rather than the colour: in the UK unleaded handles are usually green and diesel black, yet not on each forecourt.
- Inspect your filler flap. Plenty of motors state the fuel type inside the flap or on the cap. Look at it on the first fill in a motor you don't know.
- Good intentions do less than a sticker or a fob in a vivid colour on your diesel's key when a household has one of each. So mark it.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the petrol pump. It sounds daft and it does the trick.
- Mistakes like this are straightforward to make whilst your mind is on something else, and so the phone goes away.
- Some diesels have a filler designed to block a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop checking the pump.
- Stop the moment you notice. Less petrol inside that tank means a thinner mix. It does not change what to do next, which is still not to crank it.
Put petrol in a diesel in Waun-Gron already?
Then the order of things is brief. Don't crank it, and don't turn the ignition on. The attendants on the forecourt — whether at Texaco itself or wherever you filled up — will normally help push it clear of the pump if you ask. Then phone 0333 366 0103 and tell us what was put in, roughly how much, and whether it's run.
AdBlue, not petrol? Then tell us. Corrosion and deposits, not lost protection, make it a different issue — Waun-Gron has a page all for it.
Why one petrol in a diesel job around Waun-Gron costs more than another
The four scenarios above are four different jobs, so no single price for this would be fair. Which of them you are in is mostly what moves the cost. Two things come after that: the petrol that got in as a proportion of what the tank takes, then the spot the vehicle is in and whether our van can reach it safely.
What went in, how much, and whether it's run — three queries our technicians ask before pricing, not after, for precisely that reason. A range becomes a straight figure when the answers are in.
About Waun-Gron and its setting
Waun-Gron is a suburban area located near the coast in Swansea, with Waun-Gron sitting approximately 100 metres above sea level. Waun-Gron is close to the nearby communities of Tre-boeth and Penfilia, and Waun-Gron is about 2.2 miles from Swansea city centre. Waun-Gron has a mix of housing types, with semi-detached homes being predominant in the area.
Fuel drain cover across Swansea, Waun-Gron included
Tre-boeth, Lisbon and Penfilia are among the locations near Waun-Gron that the same teams work, answering petrol in diesel call-outs across Waun-Gron's SA postcode area. The car does not need to move to us: our technicians drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Waun-Gron: still at the petrol pump?
Then you are in the best spot there is. Call, and keep it switched off.