Petrol in a Diesel Car in Lisvane: How Worried Should You Be?
If it hasn't been started, you can worry far less than you likely are. Petrol sitting in a diesel tank does nothing to the motor until something pulls it through the fuel system — your ignition priming the pump, your starter, or driving on its own. So the truthful answer to the first question anyone in Lisvane asks, "have I wrecked it?", is usually no. To keep it that way, ring Petrol in Diesel and leave your motor switched off. The remainder of this page sets out what petrol actually does to a diesel, how to judge how far it has got, and how to make sure it doesn't happen to you a second time.
What petrol in a diesel does to the motor
Two jobs fall to diesel on its route round a motor. Before it combusts, it lubricates — then it burns. Designed to very fine tolerances, your injectors and the pump depend on the diesel moving through them to keep their surfaces from wearing against one another.
Of these two tasks, petrol manages the first poorly and the second never. A pump working on a petrol mixture is wearing itself out, because petrol is thinner than diesel and takes away the protection the fuel system relies on. Petrol is also designed to resist igniting under compression — the reverse of what a diesel needs from its fuel — and that is where any rattling starts.
Combined, those make the shape of the issue clear. Contact does not do the damage — movement does. All a tank with petrol in it amounts to is a fuel fault. After your pump has been labouring on that petrol, a mechanical fault has begun: anything shed by a pump that's wearing down travels downstream to the fuel injectors with your fuel.
How bad is petrol in a diesel? Four situations our technicians see around Lisvane
Fuelled, and not started: no case is better. Being on a forecourt is what makes this possible: elsewhere, the car has been driven there to begin with. With that petrol held in the tank alone, it is cleared and rinsed right where it stands, and nothing more is needed.
A brief spell of running, or just your ignition on. With your system primed, your lines and filter already contain petrol that came from your tank. That is generally still an easy job — a drain, a flush, and the fuel filter seen to.
The pump now worked a couple of miles on weakened fuel — that is what driving it meant. Tank, lines, filter, then clean fuel run through the whole system: that is this work, and the way the vehicle was driven matters as much as the distance. On the school run to the local primary school, the distance is short. Any mileage on the M4, under a mile from Lisvane, means your engine has worked hard throughout, and a run to Cardiff, under 5 miles away, makes a very different task too.
It protested, and only then stopped: smoke, knocking, a throttle gone soft, an idle gone uneven. The motor is telling you your fuel is no longer acting like diesel. Stop wherever you are — the verge on The Oaks, a lay-by, a side street — and leave the vehicle there. The drain and flush-through still come first, and they deal with it: when a car is stopped soon, permanent damage is very rare.
Myths Lisvane people hear about petrol in a diesel
"Top it up the rest of the way with diesel and it will be fine" — a myth. It won't. Nothing is removed when you top up — your tank simply carries more of the same blend. The assumption behind the advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the reverse is true. Myth: "A current diesel can cope with a bit of petrol." A modern diesel runs its fuel through finer parts at higher pressure, which makes the lubrication matter more, not less.
"It starts, it drives, and so there is no harm" — the myth that catches more people than any other. The driver of a petrol engine fed diesel normally stops, since it will not run, and the harm stops there. Feed petrol to a diesel and it normally fires up, ticks over and pulls away as if nothing has happened — all while its pump wears. Fine and running are not the same thing.
"A drop of two-stroke oil and drive it home" — a myth, taken from a fix from years ago, for a distinct fault. What petrol has diluted remains thinned, and the petrol remains in that tank anyway.
Once the motor has been run, part of the petrol sits in the fuel filter and the lines, not the tank — and the next start sends it straight back through the pump. So the myth "drain your tank yourself and you are sorted" doesn't stand up. And, a can of petrol drained at the kerbside is genuinely hazardous.
Petrol in a diesel: how does it take place?
On purpose? Never. Through carelessness? Seldom, if ever. One way only, because of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, while the diesel one generally won't fit a petrol motor. That's how the forecourt makes it straightforward.
When habit and your car stop matching, it takes place. Hire cars, courtesy cars, and motors that are new to you. Households running one of each, petrol and diesel. A forecourt you know, only with its pumps arranged differently. Filling up in a hurry on the way to Lisvane & Thornhill, with a train to catch. Years of petrol vehicles behind you, a diesel Renault Megane in front of you on the forecourt for its first tank — that is when. With rain, a call coming in, or a car full of children to deal with, your hand simply does what it always has.
How to avoid petrol in a diesel at your next fill-up around Lisvane
- A green handle for unleaded and black for diesel is normal in the UK — yet not on every forecourt. Go by the label on the pump, not the colour.
- Plenty of vehicles state the fuel inside your filler flap or on the cap, so check it on your first fill in a car you do not know.
- 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.
- Say it before you lift it. On the first fill in a new or hired car, say "diesel" out loud before you lift the nozzle off the petrol pump. It sounds daft and it does the trick.
- Mistakes like this are straightforward to make while your mind is on something else, so your phone goes away.
- A misfuel inhibitor helps, up to a point. Some diesels have a filler designed to refuse a petrol nozzle, and add-on devices exist for cars without one. They are a safety net, not a reason to stop checking the pump.
- Noticing it halfway? Stop there and then. A thinner mix results from less petrol in that tank, yet the next step remains the same: don't start it.
Already put petrol in a diesel around Lisvane?
Short and simple, then, is the order of things. Starting it is out, and so is turning on the ignition. Still on the forecourt, at Sainsbury's or anywhere else? Ask the staff to help you roll it away from the petrol pump. Next, 0333 366 0103. We will ask what got in, about how much, and if it has been run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a separate fault — Lisvane has a page just for it.
One petrol in a diesel task around Lisvane costs more than another. Why?
Four different jobs lie behind the four scenarios above — which is why there's no fair single price. The situation itself does most of the work of moving your cost. Two things come after that: the petrol that got in as a proportion of what that tank takes, then the place your car is in and whether a technician can get to it safely.
Three queries come first, before quoting, instead of after — what went in, how much, has it run — and that is the reason. Given the replies, there is a straight figure rather than a range.
About Lisvane
Lisvane is a suburban area located on the northeastern edge of Cardiff, situated near the River Rhymney at an elevation of around 90 metres. Lisvane is characterized by its predominantly detached housing stock and is close to nearby places such as Thornhill, Llanishen, and Pontprennau. Lisvane sits approximately 4 miles from Cardiff city centre, making it a popular residential area for those who work in the city. Lisvane is also within commuting distance of London, which is around 131 miles away.
Fuel drain cover across Cardiff, Lisvane included
Thornhill, Llanishen and Pontprennau are among the locations near Lisvane that the same vans work, answering petrol in diesel call-outs across Lisvane's CF postcode area. The car does not need to come to us: we drain at a forecourt, in a supermarket car park, in a lay-by or on your own drive.
At the petrol pump around Lisvane, right now?
Then you are in the best place there can be. Keep it off. Ring.