How Worried Should You Be? Petrol in a Diesel Car in Merthyr Dyfan
Not started? Then less anxious than you probably are. Everyone in Merthyr Dyfan begins with "have I wrecked it?", and the honest answer is normally no: petrol resting in your tank of any diesel remains harmless until priming, cranking or driving draws it into the system. Keep it that way: leave your engine off then ring Petrol in Diesel. What petrol actually does to a diesel, how to gauge how far it has travelled, and how to stop it from happening a second time: that is the remainder of this page.
Your engine and petrol in a diesel: what goes on
Diesel has two tasks on its way through an engine. It burns, and before it combusts it lubricates. Extremely fine gaps are built into your injectors and the high-pressure fuel pump, and only your diesel running through stops those surfaces grinding together.
The second job petrol doesn't do at all, and the first it does poorly. A pump working on a petrol mixture is wearing itself out, since petrol is runnier than diesel and takes away the protection your 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's where the rattling starts.
The shape of the problem is clear when you put those together. Contact does not do the damage — movement does. Any tank with petrol in it is a fuel problem. The beginning of a mechanical one is a pump that has been working on that petrol — and whatever a worn pump sheds travels on with your fuel to the fuel injectors downstream.
Merthyr Dyfan, petrol in a diesel: four situations, from mild to serious
Filled but not once started — the best it gets. Being on a forecourt is what makes this the case: elsewhere, the vehicle has been driven there to begin with. With the petrol kept inside your tank alone, it's cleared and purged on the spot, and nothing more is needed.
Your ignition turned on, or a brief start. The system has been primed, so petrol has left your tank and got to the filter and the lines. Drain, flush, see to your filter: still normally simple.
Those few miles on the road meant your pump working on fuel thinned by petrol the whole way. How hard the car was driven matters as much as how far, and this work covers your tank, the lines, your filter and fresh fuel through the entire system. Driving the kids to the local primary school is one kind of trip. Getting as far as Cardiff, under 10 miles away, makes a very different task — as does any mileage on the M4, under 10 miles from Merthyr Dyfan, with the motor labouring hard the whole time.
Driven until it protested. Clattering, a ragged idle, smoke, a throttle that has gone soft. The fuel is not behaving like diesel any more, and the engine is telling you. Stop wherever you are — the verge on Pendine Close, a lay-by, a side street — then leave it there. A car pulled over soon very rarely has lasting damage, since the fuel drain and the flush-through, which still come first, sort it out.
What Merthyr Dyfan people get told about petrol in a diesel — and the myths in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing comes out when you top up — your tank just holds more of the same blend. A diesel fuel system does not tolerate petrol by percentage in the way that advice assumes.
Not so: a modern diesel copes with a bit of petrol. Rather, the reverse. More precise parts and higher pressure are how a modern diesel runs its fuel, and that makes the protection matter more, not less.
Myth: "If it starts and drives, there is no harm done." This is the one that catches drivers. Any petrol motor fed diesel normally will not run, so the motorist stops and the harm stops with them. A diesel fed petrol normally starts, idles and drives away as though nothing has happened, whilst your pump wears. Running isn't the same as fine.
An old fix for a different fault is behind this one. Myth: "Add some two-stroke oil and drive the vehicle home." What petrol has thinned remains diluted, and that petrol remains in your tank anyway.
The next start draws petrol back round your pump from your lines and your filter, where some of that sits after the engine has run. That is why a DIY tank drain doesn't sort it — a myth. It is also really risky to drain petrol into a can at the roadside.
Why petrol in a diesel occurs so easily
On purpose? Never. Through carelessness? Rarely, if ever. A diesel nozzle mostly won't fit a petrol car, but the slimmer petrol nozzle goes into the filler of a diesel nearly without resistance — so forecourts make this one mistake straightforward, and only in that direction.
It takes place when habit and the vehicle stop matching. Courtesy car, hire car, or a car that is brand new. Households running one of each, petrol and diesel. A forecourt you know, but with its pumps laid out differently. A train to catch, and a rushed fill on the way to Cadoxton. A new-to-you diesel Volkswagen Passat, its first fuelling, and a motorist used to petrol: precisely when it occurs. The hand does what it has always done once you add rain, a phone call or a back seat full of kids.
How to prevent petrol in a diesel at your next fill-up in Merthyr Dyfan
- Green for unleaded and black for diesel is usual in the UK — yet not on every forecourt. Go by the label on the petrol pump, not the colour.
- Plenty of vehicles state the fuel type inside your filler flap or on the cap, so check it on your first fill in a motor you don't know.
- Mark your key. In a household with one of each, a coloured fob or a sticker on your diesel's key does more than any amount of meaning to remember.
- Say it before you lift it. On your first fill in a new or hired car, say "diesel" aloud before you lift the nozzle off the pump. It sounds daft and it works.
- While you're thinking about something else, this is an easy mistake to make — so tuck your phone away.
- Add-on devices are available for vehicles without one, and some diesels are built with a filler that won't accept a petrol nozzle. Helpful — but a backstop at best, never a reason to stop checking the label.
- Less petrol means a thinner mixture, and so stop as soon as you notice — while remembering that your next step is unchanged. It is still not to crank it.
Already put petrol in a diesel in Merthyr Dyfan?
In that case, there is just a short order of things. Leave it unstarted, with the ignition off too. Yet on the forecourt, at Texaco or anywhere else? Ask the staff to help you roll the vehicle away from the petrol pump. What was put in, about how much, and if it's run: tell us that when you call 0333 366 0103.
If it was AdBlue instead of petrol, say so. That is a different problem — corrosion and deposits instead of lost lubrication — and it has its own page for Merthyr Dyfan.
Why one petrol in a diesel task around Merthyr Dyfan costs more than another
Four different jobs sit behind the four situations above — which is why there's no honest single quote. The situation itself does most of the work of moving the cost. Beyond that it is the proportion — how much petrol was put in against how much your tank holds — and after that where the vehicle is and whether a van can get to it safely.
Before any quote, not after, come three queries: your fuel that was put in, the amount, and if it's run. That is why. Those replies are what change a range into one firm number.
About Merthyr Dyfan
Merthyr Dyfan is a suburban area in the Vale of Glamorgan, situated near the coast and approximately 5.8 miles southwest of Cardiff. Merthyr Dyfan sits at an elevation of around 73 metres, with semi-detached housing being the predominant type of accommodation in the area. Merthyr Dyfan is close to nearby places such as Gibbonsdown, Cadoxton, and Colcot, and is part of the wider Cardiff urban area.
Fuel drain cover across The Vale of Glamorgan, Merthyr Dyfan included
Petrol in diesel calls around Merthyr Dyfan — part of the CF postcode area — go to vans that likewise cover the spots about it, Gibbonsdown, Cadoxton and Colcot among them. The vehicle 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 driveway.
In Merthyr Dyfan and still at the petrol pump?
The best spot there is, then — that's where you are. Ring, and leave it switched off.