Should You Worry? Petrol in a Diesel Car in Walwen
If it hasn't been started, you can worry far less than you likely are. Everyone in Walwen begins with "have I wrecked it?", and the honest answer is generally no: petrol resting in that tank of any diesel remains harmless till priming, cranking or driving draws it into the system. To leave it that way, ring Petrol in Diesel and leave the motor switched off. The rest of this page sets out what petrol actually does to a diesel, how to tell how far it has got, and how to make sure it does not happen to you again.
What petrol in a diesel does to your engine
Diesel has two tasks on its way through an engine. Before it combusts, it protects — then it burns. The high-pressure fuel pump and the fuel injectors are designed to extremely fine clearances, and the diesel passing through them is what stops those surfaces from grinding against each other.
Petrol does the first job poorly and the second not at all. Being less viscous than diesel, petrol strips away the lubrication a fuel system needs, leaving a pump on that mixture wearing itself. It is equally made to resist igniting under compression — the reverse of what a diesel needs — which is why you hear the rattling.
Put those together and the shape of the trouble is clear. Contact doesn't do the harm — movement does. A tank with petrol in it is a fuel issue. Whatever a worn pump sheds goes on, borne by your fuel, into your injectors downstream, which is why a pump that has been working on that petrol is where a mechanical fault starts.
Four situations our technicians see around Walwen: how bad is petrol in a diesel?
Fuelled but not once started — the best it gets. The petrol is inside your tank and only your tank, and the job is a drain and a flush where your car stands. This is the one scenario that can only truly occur at a forecourt, as anywhere else the car has been driven to get there.
A brief spell of running, or just the ignition on. With the fuel system primed, your lines and filter already hold petrol that came from that tank. Normally nothing more than emptying, flushing and sorting the filter, and so still easy.
Driven a couple of miles. Now your pump has spent those miles working on thinned fuel. How hard the vehicle was driven counts as much as how far, and the work covers that tank, the fuel lines, your filter and fresh fuel through the entire circuit. On the school run to Gayton Primary School, the mileage is small. Very different once more: a run to St Asaph, under 15 miles away, or some mileage on the M53, under 10 miles from Walwen, where the motor never stopped running hard.
Driven until it complained. Rattling, a lumpy idle, smoke, a throttle that has gone soft. That's your engine telling you its fuel no longer is acting like diesel. Pull up wherever you are — the verge on Bagillt Road, a lay-by, a side street — and leave the car there. A vehicle stopped early very rarely has lasting damage, because the fuel drain and the flush-through, which still go first, deal with it.
Myths Walwen motorists hear about petrol in a diesel
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Nothing is removed when you top up — that tank simply carries more of the same blend. The idea behind that advice — that diesel fuel systems tolerate petrol by percentage — is wrong.
If anything, the reverse holds. Myth: "A modern diesel can cope with a bit of petrol." At higher pressure, through more precise parts: that's how a newer diesel moves its fuel, and so the protection counts more, not less.
The myth that catches drivers off guard: if it starts and drives, it must be unharmed. Diesel in a petrol motor normally leaves a motor that will not run: the motorist stops, and so does the harm. A diesel fed petrol normally starts, ticks over and drives away as though nothing has happened, whilst the pump grinds. Running is not the same as fine.
Myth: "Add some two-stroke oil and drive the vehicle home." It is an outdated workaround for a distinct problem. That petrol is still in your tank after that, and what it has weakened isn't put back.
Once the motor has run, part of that petrol is in the filter and the fuel lines, not your tank — and the next start pulls it straight back through the pump. So the myth "drain your tank yourself and you're sorted" doesn't hold. Also, a can of petrol filled by the kerbside is truly dangerous.
How petrol ends up: petrol in a diesel
On purpose? Never. Through carelessness? Seldom, if ever. One way only, because of the nozzles: the slimmer petrol one slides inside a diesel filler with almost no resistance, whereas the diesel one generally will not fit a petrol motor. That is how the forecourt makes it easy.
Routine and your car falling out of step is when it occurs. A new car, a hire car or a courtesy car. A household with one petrol and one diesel on the driveway. A familiar forecourt with the pumps in a different order. Racing for a train outside Flint and fuelling up en route. Years of petrol cars behind you, a diesel Peugeot 308 in front of you at the forecourt for its first tank — that is when. Throw in a back seat full of kids, a phone call or rain, and the hand takes over.
How to avoid petrol in a diesel at your next fill-up around Walwen
- Check the pump, not the colour. In the UK unleaded handles are generally green and diesel black, yet not on each forecourt. The label is what counts.
- In a car you don't know, look inside the flap over the filler or at the cap before your first fill: plenty of cars print the fuel type there.
- Label the key. In a house with one of each, a coloured fob or a sticker on the 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 take the nozzle off the petrol pump. It seems silly and it works.
- Put your phone away. This is an easy mistake to make whilst you're thinking about something else.
- Add-on devices exist for motors without one, and some diesels are built with a filler that won't accept a petrol nozzle. Helpful — but a safety net at best, never a reason to stop checking the label.
- The moment you realise, stop: less petrol in your tank makes a thinner mix. What to do next doesn't change, though — still do not start the vehicle.
Already put petrol in a diesel around Walwen?
Then the order of things is brief. Leave it unstarted, with your ignition switched off too. If you are still at the forecourt — the nearest petrol station or anywhere else — ask the attendants to help you push the vehicle clear of the petrol pump. Then phone 0333 366 0103 and tell us what got in, roughly how much, and whether it's run.
AdBlue, not petrol? Then say so. Corrosion and deposits, not lost protection, make it a separate issue — Walwen has a page all for it.
One petrol in a diesel job around Walwen costs more than another. Why?
There is no fair single quote for this, because the four situations above are four different jobs. Mostly, the cost shifts with which one you are in. Two things follow that: the petrol that got in as a share of what your tank takes, then the place the vehicle is in and whether a technician can get to it safely.
What got in, how much, and if it has run — three questions we ask before pricing, not after, for exactly that reason. A range becomes a straight figure once those replies are in.
About Walwen and where it is
Walwen is a small coastal village in Flintshire, situated near the mouth of the Dee Estuary at an elevation of around 8 metres. Walwen lies within a short distance of several nearby settlements, including New Brighton and Whelston, and is close to the city of St Asaph. Walwen has a population of approximately 602 people, predominantly living in semi-detached housing.
Walwen and Flintshire: where our fuel drain cover reaches
Our vans answering petrol in diesel calls in Walwen, in the CH postcode area, equally work the places around it, New Brighton, Whelston and Pentre-bach among them. You need not bring your vehicle to us. Forecourts, supermarket car parks, lay-bys and your own drive are all places we drain.
In Walwen and still at the pump?
In that case, you could not be in a better position. Keep the car turned off, and ring.