--- title: Rhyd-y-fro: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/rhyd-y-fro-neath-port-talbot/ location: Rhyd-y-fro county: Neath Port Talbot latitude: 51.732580 longitude: -3.861920 service: AdBlue in a Diesel Tank updated: 2026-10-27 --- # How It Occurs and How to Avoid It: AdBlue in a Diesel Tank in Rhyd-y-fro Keep your motor and ignition off then call 0333 366 0103 first — reading can wait when AdBlue is already in your diesel tank. Normally, if your engine has not turned, it's drained and fully purged where your car sits around Rhyd-y-fro. Here in advance? Then the rest covers why it happens and how to stop it happening at all. ## Two fillers, two tanks: AdBlue in a diesel car Plenty of modern diesels in Pontardawe, like those in Rhyd-y-fro, carry on two fluids; your motor takes just the diesel. Your exhaust, not the motor, is where AdBlue goes: dosed into the fumes to fresh them, from a separate tank. There is a filler for each tank. Other vehicles keep the AdBlue filler in the boot or under the bonnet; a lot of others place the two side by side under one flap. Filling the diesel side at the petrol pump goes on all the time. The AdBlue side is fuelled far less often, normally from a bottle, and usually by someone who has to stop and think where it goes. Mistakes happen in that gap between them. ## Rhyd-y-fro: how AdBlue in the diesel tank occurs It's hardly ever carelessness. Three things tend to line up. On a drive off Waun Penlan before work, or in the car park outside the pub in the village on the way home: that is where the hurried top-up happens. Why the rush? As AdBlue gets low your car tells you, and once it's gone, limp mode kicks in. The old car's filler is where the hand reaches — yet a hire car, a new vehicle or a company car keeps the fillers elsewhere. That is the second factor: a new motor. And the bottle fits. A bottle with a spout goes into a diesel filler as easily as an AdBlue one, and so nothing stops the pour after it has started. Whether it happens in Llangiwg or the middle of Rhyd-y-fro, it's the same few seconds. ## How to tell the AdBlue filler from the diesel one Before you pour anything, whether on a driveway in Ynysmeudwy or a forecourt around Rhyd-y-fro, check these. They take a few seconds. - Colour and lettering: an AdBlue cap is regularly blue, or says "AdBlue", where a diesel cap normally does not. Trust the cap, not its position. - The size. On plenty of motors the AdBlue filler neck is the smaller of the two. - A label inside your fuel flap often says which fuel goes where, on plenty of vehicles. Look for it. - In your boot or under the bonnet: that's where your filler is if it is not by the diesel cap, and the handbook says which. - Collecting a hire or company car, say at the car park outside Skewen? Ask the person who drove the car last before you set off, not when the light goes on. ## AdBlue top-ups that never reach your diesel tank A routine for the day the light comes on, wherever around Neath Port Talbot that is. - Not in a rush on the side of Commercial Road, not on a slope, not with the motor running: park then switch off first. - Say "AdBlue" out loud as you unscrew the cap, once you find the AdBlue filler and reading it. Daft, perhaps, yet it works. - The two behind one flap? Then confirm the lid on the diesel filler stays shut ahead of raising the bottle. - Gently does it, through the bottle's own spout, until it is full or the bottle runs out. - Close the cap and check again. Make sure your diesel cap was never opened. Only then start the car. Discover during the second or third step that the bottle went in the diesel filler? That's where you stop. Step five stays out. ## Put AdBlue in your diesel tank around Rhyd-y-fro already? Don't start your motor: that's where the short order of things begins. Keep your ignition off as well, because on plenty of diesels switching it on alone runs your pump. Topping up with diesel won't thin it: rather than mixing, AdBlue drops to the base of that tank, right where the fuel is taken from. The staff at Tesco, another forecourt nearby or another forecourt will usually lend a hand to push your car clear if asked. Leave it where it is if you're on your own drive in Rhyd-y-fro. Stop as soon as it is safe and switch off, if your engine has already run. The next junction means the place to leave when you are on the M4, under 5 miles from Rhyd-y-fro. About how far did it go? Hopping across Rhyd-y-fro is smaller a job than a trip of under 10 miles to Swansea, and so say. ## When our engineers turn up around Rhyd-y-fro, what happens? We come to the car wherever it has stopped, whether that is outside the local primary school, near Tŷ'r Gwrhyd or on your own drive. Both the work and the quote depend on three answers — which liquid, what amount, and whether it has run — so our technicians ask. No one heads out until you've heard the price by phone. The system is then purged thoroughly, after the tank is cleared. Much more than with petrol, it counts with AdBlue: the crystals build up, some metals are attacked, and none of that washes away unaided, no matter how long it is left. The filter is flushed, or replaced where it needs to be; fresh diesel goes in; and the car is tested. We do not go until it has been started and is running properly. Using pumps fine on a working forecourt and quiet enough for use outside a house at night, most jobs in which the motor hasn't run take about half an hour once our engineers are there. Nothing upfront; you settle up that day. Afterwards, a VAT invoice and the report from the engineer go to you for the insurer. Before we get there, have a look at your policy; many carry cover for misfuelling. ## About Rhyd-y-fro itself Rhyd-y-fro is a suburban area in Neath Port Talbot, situated near the river and close to the communities of Llangiwg and Gellygron. Rhyd-y-fro has a mix of semi-detached housing and is located near Craig Llangiwg, with Swansea just 8.5 miles away. Rhyd-y-fro sits at an elevation of 109 metres, in a region of south Wales with a strong industrial heritage. ## AdBlue drains about Rhyd-y-fro, and Neath Port Talbot beyond Gellygron and Craig Llangiwg are among the places around Rhyd-y-fro, a residential suburb, that the same vans cover, over SA postcodes. A postcode starting SA8 3 gets our van to you fastest. Your car stays put. A driveway, a lay-by on the way to Pontardawe Golf Club, a side street close to Pontardawe Arts Centre: we drain it where it is. Awkward to pin down, like the back of Pontardawe Library? Close to a county line? Checking is better than guessing, so ring. ## Rhyd-y-fro drivers: the short version Before you tip, read the cap. Petrol in Diesel empties it on the spot, anywhere around Neath Port Talbot, if AdBlue has gone in your diesel tank regardless — and so leave the car off then ring 0333 366 0103.