--- title: Coalbrookvale: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/coalbrookvale-blaenau-gwent/ location: Coalbrookvale county: Blaenau Gwent latitude: 51.778350 longitude: -3.168240 service: AdBlue in a Diesel Tank updated: 2026-10-14 --- # Coalbrookvale: How Does AdBlue End Up in a Diesel Tank, and How Do You Avoid It? Pause here for a moment if the diesel tank already has AdBlue in it: ignition off, engine off, and call 0333 366 0103. Caught before the motor runs, it's generally a drain and a thorough flush, done where your car is around Coalbrookvale. If you're reading before it has happened, the rest of this page is about why it takes place and how to make sure it doesn't. ## Why does AdBlue in a diesel motor need its own filler? No single fluid but two: that's what many modern diesels around Coalbrookvale and Cwmcelyn carry, with diesel feeding your motor. AdBlue goes to your exhaust, where it is sprayed into the gas to fresh it, and it lives in a tank of its own. Different tanks, different fillers. Under one flap, next to each other: that is the arrangement on a lot of motors. Elsewhere, AdBlue's filler is beneath the bonnet or in your boot instead. Filling your diesel side at the petrol pump goes on all the time. Someone who has to stop and think where it goes normally tops up the AdBlue side, from a bottle, and far less often. Mistakes happen in the gap between them. ## How does AdBlue in your diesel tank take place around Coalbrookvale? Three things tend to line up, and carelessness is rarely one of them. The warning comes first. As AdBlue runs low your car tells you, and if it runs out altogether, your vehicle goes into limp mode. So the top-up is done in a hurry: on a drive off Dale View before work, or in the car park outside the pub in the village on the way home. Then the car is new. A hire car, a new motor or a company car puts the fillers where your last one did not, and the hand gets to for the cap it would have used on the old one. A spouted bottle meets no obstacle at a diesel filler no more than at an AdBlue one. So the pour, once begun, carries on. Nantyglo or the middle of Coalbrookvale: it takes the same few seconds either way. ## The AdBlue filler and the diesel filler: telling them apart A couple of seconds is all these take — so run through them before you pour anything, on a drive in Winchestown or a forecourt in Coalbrookvale. - Where it sits can mislead; the cap doesn't. AdBlue caps are often blue or bear the word "AdBlue" — diesel ones normally do not. - Plenty of motors give AdBlue the smaller filler of the two. - Look inside your fuel flap: plenty of cars carry a label there showing which fuel goes where. - Cannot see it next to your diesel filler? Then look beneath the bonnet or inside your boot — the handbook will say which. - Picking up a hire or company car, say at the car park outside Ebbw Vale Town? Check with whoever drove the car last before leaving, not when the light comes on. ## How to top up without AdBlue in the diesel tank Wherever across Blaenau Gwent the light comes on, here is a routine for that day. - Stop somewhere level, engine off, with time in hand — not rushing on the side of Farm Road. - Say "AdBlue" out loud as you unscrew the cap, after you find the AdBlue filler and reading it. Silly, perhaps, but it does the trick. - Leave the diesel cap on. If both sit under one flap, check the diesel cap is still closed before you lift the bottle. - Using the bottle's own spout, pour slowly — and stop when it is full or the bottle is empty. - Close the cap and check a second time. Make sure the diesel cap was never opened. Only then start the car. Discover during the second or third step that AdBlue went into the diesel tank? That is where you stop. Never go on to step five. ## Put AdBlue in your diesel tank in Coalbrookvale already? The short order of things, starting with no starting your engine. The fuel pump runs on plenty of diesels the moment the ignition goes on — and so leave it off. Don't top up with diesel to thin it: AdBlue does not mix with diesel, it sinks to the bottom of the tank, where the fuel is drawn from. Ask the staff to help roll the car clear of the pump if you're at a forecourt — the Texaco, the Gulf or anywhere else. On your own drive around Coalbrookvale? Then your car stays where it is. Where your engine has been run by now, pull over somewhere safe and turn the car off. On the M4, under 15 miles from Coalbrookvale, that means the next junction. A short hop across Coalbrookvale is a smaller job than a run towards Newport, under 25 miles away, and so tell us roughly how far it went. ## Our arrival around Coalbrookvale, and what occurs next Anywhere the car has stopped, be it by the local primary school, beside Trevor Rowland memorial or at home, the van comes to it. Both the work and our price depend on three replies — what fluid, which amount, and if it's run — so we ask. That quote is given on the call, ahead of any van leaving. Next: draining, then a full flush of the whole system. AdBlue crystallises and is corrosive to some of the metals in a fuel system, and so it does not wash out on its own — which is why the flush counts more with AdBlue than with petrol. Testing is at the end: before that, fresh diesel is added, and your filter is flushed or replaced as needed. Before leaving, our technicians start it and check that it is running properly. Most jobs are finished in roughly half an hour after we arrive, provided the engine hasn't run — and the pumps our technicians use are fine on a live forecourt and quiet at night beside a house. You pay on the day, with nothing upfront, and get a VAT invoice and an engineer report for your insurer. Many insurance policies include misfuelling cover, so it's worth checking yours while we're on the way. ## About Coalbrookvale and where it is Coalbrookvale is a locality in the county of Blaenau Gwent, situated inland at an elevation of 322 metres. Coalbrookvale lies near the communities of Nantyglo, Coedcae, and Garn Fach, and is approximately 15 miles from the city of Newport. Coalbrookvale has a population of around 1304 people, predominantly residing in terraced housing. Coalbrookvale is characterised by its residential layout and proximity to the surrounding Welsh countryside. ## AdBlue drains across Blaenau Gwent, Coalbrookvale included Coedcae and Garn Fach are among the towns around Coalbrookvale, a small village, that the same teams cover, throughout NP postcodes. Quickest of all: quote a NP23 4 postcode to our van. The vehicle does not need to move. Anywhere it stands — near Nantyglo and Blaina War Memorial, in a layby en route to Trevor Rowson Park, on a drive — that's where it gets cleared. Awkward to explain, like the back of Holy Trinity & St Anne? By a border? Checking is better than guessing, so ring. ## For Coalbrookvale drivers, the short version Pour no AdBlue till you've read the cap. Petrol in Diesel empties it where it stands, anywhere across Blaenau Gwent, if AdBlue has gone in the diesel tank regardless — so leave it off then phone 0333 366 0103.