--- title: AdBlue in a Diesel Tank Upper Coedcae? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/upper-coedcae-torfaen/ location: Upper Coedcae county: Torfaen latitude: 51.774480 longitude: -3.074420 service: AdBlue in a Diesel Tank updated: 2026-10-24 --- # Preventing AdBlue in a Diesel Tank in Upper Coedcae: Why It Happens Leave the engine and ignition off and phone 0333 366 0103 first — reading can wait if AdBlue is already in your diesel tank. Usually, if your motor hasn't run, it is drained and fully cleaned where the vehicle sits in Upper Coedcae. Not happened yet? Below, the page covers the reasons it occurs and the how to avoid it altogether. ## Two fillers, two tanks: AdBlue in a diesel car Not one liquid but two: that is what plenty of newer diesels near Upper Coedcae and Blaenavon Junction carry, with diesel for the motor. Your exhaust, not your motor, is where AdBlue ends up: dosed into the gas to fresh it, from a separate tank. Different tanks, separate fillers. Under one flap, side by side: that's the arrangement on many vehicles. On others, AdBlue's filler sits beneath the bonnet or in your boot instead. Diesel goes in at every filling station visit, week in, week out. Someone who has to stop and work out where it goes usually fills the AdBlue side, from a bottle, and far less often. The error lives in that gap. ## Upper Coedcae: how AdBlue in your diesel tank takes place It's hardly ever carelessness. Three things tend to line up. To start with, the warning. Low AdBlue brings a warning from the car, and running dry means limp mode — hence a rushed top-up, maybe before work off Coed Llwyd Close, perhaps outside The Fountain on the way home after work. New-to-you vehicles are second, too. Hire cars, new motors and company cars put their fillers differently, and habit reaches for the cap used on the old one. Nothing stops the tip once it has started, since a bottle with a spout goes into a diesel filler as readily as an AdBlue one. The bottle fits. It's seconds, whether out in Middle Coedcae or bang in the centre of Upper Coedcae. ## Telling the AdBlue filler from your diesel filler Check these before pouring, on a forecourt around Upper Coedcae or a drive over in Forge Side. Seconds, that's all. - The cap. The AdBlue cap is frequently blue, or marked "AdBlue". Your diesel cap usually isn't. Read it instead of going by where it sits. - Look at the size: the smaller filler neck is, on many vehicles, the AdBlue one. - The flap. Look inside your fuel flap for a label. Plenty of motors say there which fuel goes where. - Cannot find it beside the diesel inlet? In that case look beneath the bonnet or in your boot — the owner's manual will say which. - Collecting a hire or company car, say at the car park outside Abergavenny? Check with whoever drove the car last before leaving, not when the light comes on. ## Keeping AdBlue out of your diesel tank when you top up A routine for the day the light comes on, wherever in Torfaen that is. - Not in a rush on the side of Upper Coedcae Road, not on a slope, not with your motor running: park then switch off properly. - Daft as it sounds, speaking "AdBlue" out loud while you unscrew the cap does the trick — after you've found your filler and read the cap. - The two behind one flap? Then confirm the cap on the diesel filler is still closed before lifting the bottle. - Using the bottle's own spout, pour slowly — and stop when it's full or the bottle is empty. - Only after that, start the car: close the cap, check a second time, and make sure your diesel cap was never opened. If at stage two or three you find you have already poured into your diesel side, stop there. Leave out step five entirely. ## Upper Coedcae: already put AdBlue in the diesel tank? Short order, then. First: the engine stays unstarted. Leave your ignition off as well, because on many diesels it by itself runs your fuel pump. AdBlue does not mix with diesel — it sinks to the bottom of that tank, where the fuel is sucked from — so do not top up with diesel to dilute it. On a forecourt — Shell, Gulf or another — the attendants will normally help roll the vehicle clear, when you ask. Leave it where it is if you are on your own drive around Upper Coedcae. Where your engine has been run by now, pull over somewhere safe and turn the vehicle off. On the M4, under 15 miles from Upper Coedcae, that means the next exit. Tell us about how far it went: a run towards Newport, under 15 miles away, is a bigger job than a short hop across Upper Coedcae. ## Upper Coedcae: what occurs when our technicians get there Our technicians come to the car wherever it has stopped, whether that's outside the local primary school, near The Hwb or on your own drive. The replies settle the work and the quote, and so our engineers ask what got in, about how much, and if it's run. No one sets off before you've heard our quote by phone. Draining the tank comes next, then a thorough flush of the fuel system. With AdBlue that counts more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, so it does not wash out on its own. A test is last: before that, fresh diesel is added, and the fuel filter is flushed or replaced as needed. The engine is fired up next and tested to make sure it runs properly, all before we go. If the motor has not run, most jobs take about half an hour once we are there, using pumps that are fine on a working forecourt and quiet enough to use outside a house at night. Paying happens on the day, not upfront, and you receive the documents your insurer asks for: an engineer report and a VAT invoice. While we travel, have a look at your insurance documents; plenty include cover for misfuelling. ## About Upper Coedcae and where it is Upper Coedcae is a suburban area situated on the riverside in Torfaen, with a mix of terraced housing and a relatively high elevation of 384 metres. Upper Coedcae lies near the communities of Middle Coedcae and Blaenavon, and is connected to the city of Newport, which is approximately 13 miles away. Upper Coedcae has a population of around 3605 people, and its location reflects the blend of industrial and natural heritage found in this part of Wales. ## AdBlue drains in Upper Coedcae and across Torfaen As a residential suburb, Upper Coedcae shares its vans surrounding places — Blaenavon, Rifle Green — all the way across NP postcodes and the wider area beyond. Fastest of all: give a NP4 9 postcode for the van. Shifting your car isn't necessary. Wherever it sits — beside Bethlehem Congregational Chapel, on a lay-by heading to Blaenafon Town Centre Conservation Area, at home — that is where it is cleared. Ring and ask instead of assuming if you are near a border, or somewhere hard to explain, like the back of Horeb Baptist Church. ## The short version for Upper Coedcae people Tip no AdBlue till you have read the cap. If AdBlue has gone in your diesel tank anyway, leave the vehicle off then ring 0333 366 0103. Petrol in Diesel clears it where it stands, anywhere in Torfaen.