--- title: Cullompton: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/cullompton-devon/ location: Cullompton county: Devon latitude: 50.855200 longitude: -3.392760 service: AdBlue in a Diesel Tank updated: 2026-10-24 --- # AdBlue in a Diesel Tank in Cullompton: Why It Happens and How to Stop It AdBlue already in the diesel tank? Then put this page down for now, leave your ignition and motor off, and call 0333 366 0103. Usually, if the motor hasn't run, it is emptied and thoroughly purged where your vehicle sits in Cullompton. Reading in advance? Then the rest explains how it comes about and what to stop it happening at all. ## Two fillers, two tanks: AdBlue in a diesel vehicle Diesel goes to your motor — yet plenty of newer diesels driven around Cullompton and Knowle carry another fluid as well. AdBlue goes to your exhaust, where it is sprayed into the gas to fresh it, and it lives in a tank of its own. Each tank has its own filler. Many of cars share a single flap for both, while some put the AdBlue filler to your boot or under the bonnet. At the petrol pump, the diesel side is topped up all the time. Much less frequently, the AdBlue side gets topped up — normally from a bottle, by someone thinking about where it goes. The mistake grows in the gap between them. ## How does AdBlue in your diesel tank happen around Cullompton? Carelessness seldom explains it. What does is three things lining up at once. The warning comes first. As AdBlue runs low the car tells you, and if it runs out completely, your vehicle drops into limp mode. So the top-up is done in a hurry: on a drive off Cockpit Hill before work, or in the car park outside Pony and Trap on the way home. New-to-you cars come next, as well. Hire cars, new cars and company motors put their fillers in new places, and habit reaches for the cap it used on the old one. Third, the bottle fits: diesel filler or AdBlue filler, it slides in as readily, and after the pour starts, no part stops it. Stoneyford or the middle of Cullompton: it is the same few seconds in both. ## Which filler is for AdBlue, and which for diesel? A couple of seconds is all these take — so run through them before you tip anything, on a driveway in Ponsford or a forecourt around Cullompton. - The cap. The AdBlue cap is commonly blue, or marked "AdBlue". Your diesel cap normally isn't. Read it instead of going by position. - Many vehicles fit AdBlue the smaller filler of the two. - A label inside your fuel flap frequently shows which fuel goes where, on many motors. Look for it. - Cannot see it next to your diesel inlet? Then look below the bonnet or in the boot — the owner's manual will say where. - The previous driver knows. Ask as you collect a rental or company car — from Tiverton Parkway's car park, perhaps — not when the warning comes on. ## How to top up without AdBlue in your diesel tank A routine for the day the light comes on, wherever in Devon that is. - Pull in somewhere level, engine off, with time in hand — never rushing on the side of Fore Street. - Locate the AdBlue filler, check the cap, and speak the name "AdBlue" out loud as you unscrew it. It seems daft. It does the trick. - If both sit under one flap, check your diesel cap is still closed before you lift the bottle — then leave the vehicle on. - Using the bottle's own spout, pour slowly — and stop when it is full or the bottle is empty. - Before starting the car, close the cap and check again that the diesel cap was never came off. If at step two or three you find you have already poured into the diesel side, stop there. Don't carry on to stage five. ## Cullompton: already put AdBlue in the diesel tank? Short list, then. Top of it: the motor remains off. Don't switch the ignition on; on plenty of diesels that alone runs the fuel pump. Topping up with diesel will not weaken it: instead, AdBlue drops to the bottom of your tank, right where fuel is taken from. If you are on a forecourt, whether it is the Gulf or the Tesco, ask the attendants to help roll the car clear of the petrol pump. Your own driveway in Cullompton is the place it should stay. If your engine has already run, stop as soon as it is safe and switch off. Cullompton sits under a mile from the M5; on it, take the next junction. Tell us about how far it went: a run towards Exeter, under 15 miles away, is a bigger job than a short hop across Cullompton. ## What occurs when we turn up in Cullompton Our van reaches the vehicle wherever it stopped — your own drive, near Cullompton Library, or outside St Andrew's Primary School. The answers decide this work and our price, so our engineers ask what got in, roughly how much, and if it has run. You hear that price by phone, before anyone heads out. Emptying the tank comes next, followed by a full flush of your system. With AdBlue that counts more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, and so it doesn't wash out on its own. Your filter is flushed, or replaced where it needs to be; clean diesel goes in; and the car is tested. We don't leave until it has been started and is running smoothly. Most jobs are finished in roughly half an hour after our engineers get there, as long as the motor has not run — and the pumps we use are safe on a live forecourt and quiet at night beside a house. Payment happens on the day, not upfront, and you receive the paperwork an insurer asks for: an engineer report and a VAT invoice. Plenty of insurance policies include misfuelling cover, and so it is worth checking yours whilst we are on the way. ## About Cullompton itself Cullompton is a town in Devon, situated on the River Culm at an elevation of 62 metres, with a mix of semi-detached housing and other residential properties. Cullompton lies near the M5 motorway, approximately 11 miles from Exeter, and is surrounded by smaller settlements like Stoneyford and Colebrook. Cullompton has a population of around 10,171 people and is located in the South West region of England, about 148 miles from London. Cullompton's riverside setting has influenced its development over time, with the town expanding along the river valley. ## Cullompton and Devon: AdBlue drains across the area Over EX postcodes, our teams covering Cullompton — a riverside town — work the surrounding locations too, Colebrook and St Georges Well included. Quote a postcode that starts EX15 1, and our van gets there fastest. Your car doesn't need to shift. Wherever it stands — near Hebron Evangelical Church, in a lay-by heading to Cullompton Community Association Fields, at home — that is where it is drained. If you're close to a boundary, or somewhere hard to explain like the back of Pound Square Unitarian Chapel, ring and ask rather than assuming. ## The short version for Cullompton drivers Tip no AdBlue till you've read the cap. AdBlue in your diesel tank after all? Leave the vehicle switched off and phone 0333 366 0103; Petrol in Diesel drains it on the spot, across Devon.