--- title: South Cerney: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/south-cerney-gloucestershire/ location: South Cerney county: Gloucestershire latitude: 51.672110 longitude: -1.930480 service: AdBlue in a Diesel Tank updated: 2026-10-20 --- # South Cerney: How Does AdBlue End Up in a Diesel Tank, and How Do You Prevent It? If AdBlue is already in your diesel tank, stop reading for a moment: leave the motor and your ignition off and ring 0333 366 0103. In South Cerney, catching it before the motor runs normally leaves draining and a full flush on the spot. Reading in advance? In that case what follows explains why it happens and what to stop it ever happening. ## Why does AdBlue in a diesel vehicle need its own filler? No single liquid but two: that is what plenty of newer diesels around South Cerney and Shorncote carry, with diesel for your motor. AdBlue's own tank holds it, and from there it is sent to your exhaust, and there spraying treats the gas. Each tank has its own filler. Many of cars have a single flap for both, whereas some move the AdBlue filler to the boot or under the bonnet. Diesel goes in at each forecourt visit, again and again. The AdBlue side is topped up far less often, usually from a bottle, and normally by a person who has to stop and think where it goes. The mistake grows in that gap between them. ## How does AdBlue in the diesel tank occur in South Cerney? It's hardly ever carelessness. Three things tend to line up. Hurry comes from the warning. The vehicle warns you as AdBlue runs low, and an empty tank sends the vehicle into limp mode — so the top-up happens quickly, before work on a drive off High Street, or heading home in the car park outside The George. New-to-you motors come next, as well. Hire cars, new vehicles and company cars put their fillers differently, and habit goes for the cap it used on the old one. No part halts 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 takes seconds, be it in Upper Up or right in the heart of South Cerney. ## Which filler is for AdBlue, and which for diesel? Check these before pouring, at a forecourt in South Cerney or a drive out in Cerney Wick. Seconds, no more. - Position misleads; the cap does not. AdBlue caps are often blue or carry the word "AdBlue" — diesel ones normally don't. - On many motors, the size gives it away: AdBlue has the smaller filler neck. - Open the filler flap and look for a label — many vehicles show what belongs in which inlet right there. - The handbook shows which it is when the filler isn't next to the diesel cap: the boot, or under the bonnet. - Whoever had it before knows. Ask when you pick up a rental or company car — at Kemble's car park, say — rather than once the light appears. ## Topping up AdBlue without it reaching the diesel tank Anywhere in Gloucestershire the light comes on, here is a routine for that day. - Turn off after you park — level ground, engine stopped, and not in a rush beside Station Road at the roadside. - Daft as it sounds, saying "AdBlue" aloud as you unscrew the cap works — once you've located your filler and read it. - If both sit under one flap, check the diesel cap is still closed before you lift the bottle — then leave the car on. - Using the bottle's own spout, pour slowly — and stop when it is 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. Find at stage two or three that it's already gone into your diesel side? Then stop just there. Leave out step five entirely. ## AdBlue in your diesel tank already, around South Cerney? Then the order of things is short. Do not start your engine. The fuel pump runs on many diesels the moment the ignition goes on — so leave it off. Diluting it with extra diesel fails, since AdBlue settles to the base rather than blending — and that is where your fuel is pulled from. If you're at a forecourt, whether it's the Tesco or the Esso, ask the staff to help roll your car clear of the petrol pump. If you are on your own drive around South Cerney, leave the vehicle where it sits. If your motor has already run, stop as soon as it is safe then switch off. On the M4, under 10 miles from South Cerney, that means the next exit. About how far did it go? Crossing South Cerney is less a job than a run of under 25 miles towards Gloucester, so say. ## What happens when our engineers turn up in South Cerney Our van reaches your car wherever it stopped — your own drive, near South Cerney Cross, or outside Ann Edwards Church of England Primary School. Our technicians ask what was put in, about how much, and if it has run, since the replies decide the work and our quote. No one sets off until you've had our price by phone. Next: a drain, then a full flush of the whole system. Much more than with petrol, it matters here: crystals build up, some metals are attacked, and none of that washes out on its own, however long it sits. After your filter is flushed — or replaced, if needed — fresh diesel is added, and then your car gets tested. The motor is fired up next and checked to make sure it runs correctly, all before our technicians go. Most jobs are done in about half an hour after we get there, as long as the engine has not run — and the pumps we use are fine on a busy forecourt and quiet after dark outside a house. You pay on the day, with nothing upfront, and get a VAT invoice and an engineer report for your insurer. It's worth looking at your insurance as the van travels to you: misfuelling cover is included with many policies. ## About South Cerney South Cerney is a village in Gloucestershire, situated on the shores of a lake at an elevation of 93 metres, with a mix of detached homes and other residential properties. South Cerney lies near the Cotswold Community and other nearby places such as Upper Up and North End, and is approximately 19 miles from Gloucester. South Cerney has a population of around 2046 people and is located in a scenic area popular for outdoor activities. South Cerney is also within commuting distance of larger cities, being about 78 miles from London. ## AdBlue drains in South Cerney and across Gloucestershire Throughout GL postcodes, our vans covering South Cerney — a village — work the nearby locations too, North End and Cotswold Community among them. Quote a postcode that starts GL7 5, and the van arrives fastest. Shifting the vehicle is not necessary. Draining takes place right there, whether a drive, a road by All Hallows Parish Church, or a layby towards Upper Up Playing Field. Ring and ask rather than guessing if you're near a border, or somewhere hard to describe, like the back of Cotswolds Water Park. ## The short version for South Cerney people Read the cap before you tip. If AdBlue has gone in your diesel tank anyway, leave the car off then ring 0333 366 0103. Petrol in Diesel empties it where it stands, anywhere around Gloucestershire.