--- title: Explained: AdBlue in a Diesel Tank Liswerry canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/liswerry-newport/ location: Liswerry county: Newport latitude: 51.580430 longitude: -2.958050 service: AdBlue in a Diesel Tank updated: 2026-10-17 --- # Liswerry: How Does AdBlue End Up in a Diesel Tank, and How Do You Prevent It? Leave the motor and ignition off then ring 0333 366 0103 now — the rest can wait when AdBlue is already in your diesel tank. Around Liswerry, catching it before your engine runs normally means draining and a thorough flush where it stands. The rest of this page explains why it happens and how to make sure it does not — handy if you're reading ahead of time. ## AdBlue in a diesel vehicle, and its separate tank Many modern diesels in Bishpool, like those in Liswerry, run on two liquids; your motor takes only the diesel. Your exhaust, not your engine, is where AdBlue ends up: sprayed into the gas to fresh it, from a separate tank. Each tank has its own filler. Many of vehicles have a single flap for both, while others move the AdBlue filler to the boot or under the bonnet. The diesel side is filled at the pump all the time. Someone who has to stop and work out where it goes usually fills the AdBlue side, from a bottle, and far less frequently. The mistake grows in that gap between them. ## How AdBlue in the diesel tank takes place in Liswerry Three things tend to line up, and carelessness is seldom one of them. The warning comes first. As AdBlue runs low your car tells you, and if it runs out altogether, the vehicle goes into limp mode. So the top-up is done in a hurry: on a driveway off Lliswerry Road before work, or in the car park outside Lliswerry & Nash Constitutional Club on the way home. The old car's filler is where your hand goes — but a rental car, a new car or a company car puts the fillers somewhere else. That is the second thing: an unfamiliar car. And the bottle fits. A bottle with a spout goes into a diesel filler as easily as an AdBlue one, so nothing stops the pour after it has started. Somerton or the heart of Liswerry: it is the same few seconds either way. ## Telling the AdBlue filler from the diesel filler Whether a Liswerry forecourt or a driveway over in Lawrence Hill, spend a couple of seconds over these before anything is poured in. - The cap. The AdBlue cap is commonly blue, or marked "AdBlue". The diesel cap normally isn't. Read it rather than going by position. - Many cars give AdBlue the smaller filler of the two. - Look inside the fuel flap: plenty of cars have a label there saying which fuel goes where. - Can't find it beside the diesel inlet? Then look beneath the bonnet or inside your boot — the handbook says where. - Whoever had it before knows. Check when you collect a hire car or company car — from Newport (South Wales)'s car park, say — rather than when the warning comes on. ## AdBlue top-ups that never reach your diesel tank A routine for the day the light comes on, wherever across Newport that is. - Not in a rush on the side of Nash Road, not on a slope, not with your engine running: park then switch off first. - Find the AdBlue filler, read the cap, and say the word "AdBlue" out loud as unscrewing it. It seems daft. It does the trick. - The diesel cap stays on. When the two sit under a flap, confirm it's shut before the bottle comes up. - Using the bottle's own spout, tip slowly — and stop when it's full or the bottle is empty. - Before starting your car, close the cap and check again that your diesel cap was never opened off. Find at stage two or three that it's already gone into your diesel side? So stop just there. Don't go on to step five. ## Already put AdBlue in your diesel tank in Liswerry? Then the order of things is short. Do not start your motor. The fuel pump starts on many diesels the moment your ignition goes on — so leave it off. Topping up with diesel will not weaken it: rather than mixing, AdBlue drops to the bottom of your tank, right where fuel is taken from. The attendants at Esso, Tesco or another forecourt will normally lend a hand to push your car away when asked. Leave it where it is if you're on your own drive around Liswerry. Already started? Pull over once it's safe, then turn off. Leave the M4 — under a mile out of Liswerry — at the next junction. A short hop across Liswerry is a smaller job than a run towards Newport, under 3 miles away, and so tell us about how far it went. ## What occurs when our technicians arrive around Liswerry Our engineers come to the car wherever it has stopped, whether that is outside the local primary school, close to Welcome to Somerton or on your own driveway. Our technicians ask what went in, about how much, and whether it has run, because those answers decide the work and our quote. During the call itself, you are told the quote — ahead of dispatch. Then that tank is emptied and your system cleaned thoroughly. Unlike petrol, AdBlue forms crystals and eats at some fuel-system metals, and none of that clears out by itself. Hence it counts more. The filter is cleaned, or replaced where it needs to be; clean diesel goes in; and the car is tested. After that our technicians fire it up and confirm it runs correctly before leaving. If your motor has not run, the majority of jobs take about half an hour once we're there, using pumps that are fine on a working forecourt and quiet enough to use outside a house after dark. You pay on the day, with nothing upfront, and get a VAT invoice and an engineer report for your insurer. It is worth checking your insurance while we travel to you: misfuelling cover is included with many policies. ## About Liswerry and where it is Liswerry is a suburban area in the city of Newport, situated near the coast of Wales at an elevation of around 9 metres. Liswerry lies close to the city centre, approximately 1.7 miles from Newport, and is surrounded by other suburban areas such as Somerton, Alway, and Beechwood. Liswerry is characterised by its predominantly semi-detached housing stock, reflecting the typical residential development of the region. Liswerry is home to a population of around 7373 people, according to recent estimates. ## AdBlue drains around Liswerry, and Newport beyond Throughout NP postcodes, the teams covering Liswerry — a residential suburb — work the surrounding places too, Beechwood and Alway included. The van reaches you fastest with a postcode starting NP19 4. The car stays where it is. A driveway, a lay-by on the way to Hillview Crescent Park, a side street close to Newport East Community Centre: we drain the vehicle where it sits. If you are near a boundary, or somewhere hard to describe like the back of Inspire and Create, ring and ask rather than assuming. ## Liswerry motorists: the short version Pour no AdBlue till you've read the cap. Petrol in Diesel drains it on the spot, anywhere in Newport, if AdBlue has gone in the diesel tank all the same — and so leave the vehicle off and phone 0333 366 0103.