--- title: AdBlue in a Diesel Tank Portishead: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/portishead-somerset/ location: Portishead county: Somerset latitude: 51.485320 longitude: -2.768250 service: AdBlue in a Diesel Tank updated: 2026-10-24 --- # Portishead: 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. Usually, when the motor has not turned, it's drained and thoroughly rinsed where your vehicle is around Portishead. Here before the event? In that case what follows explains why it happens and what to prevent it ever happening. ## AdBlue in a diesel vehicle: two tanks, two fillers Plenty of newer diesels on the roads around Portishead and North Weston carry two liquids, not one. Diesel goes to your motor. The exhaust, not your engine, is where AdBlue goes: sprayed into the fumes to clean it, from a separate tank. Each tank has its own filler. Many of motors have a single flap for the two, whereas some put the AdBlue filler to your boot or under the bonnet. Topping up the diesel side at the pump happens all the time. A driver who has to stop and think where it goes usually fills the AdBlue side, from a bottle, and much less often. The slip lives in that gap. ## How AdBlue in the diesel tank happens around Portishead Seldom is it carelessness: normally three things line up. First, the warning. Low AdBlue triggers a message from the vehicle, and letting it run out means limp mode — so a hurried top-up, perhaps before work off High Street, perhaps at Portishead Working Mens Club on the way home after work. Next, your hand goes for the cap it knew on the old motor — since a rental car, a new car or a company car puts the fillers somewhere your last one didn't. And the bottle fits. A bottle with a spout goes into a diesel filler as easily as an AdBlue one, and so nothing stops the pour once it has started. The same few seconds settle it, in the middle of Portishead or out in Dry Hill. ## Telling the AdBlue filler from the diesel filler Whether a Portishead forecourt or a drive out in Sheepway, spend a couple of seconds over these before anything is poured in. - Check the cap instead of going by position: AdBlue caps are often blue or marked "AdBlue", and diesel caps usually aren't. - Many motors give AdBlue the smaller filler of the two. - Lift the filler flap and check for a label — many vehicles show what goes in which filler right there. - The handbook. If the filler is not by the diesel cap, it is in your boot or under the bonnet, and the handbook says which. - The person who drove it last. On a hire or company car picked up from somewhere like the car park outside Avonmouth, ask before you leave, not when the light comes on. ## AdBlue top-ups that never reach your diesel tank When the light goes on, anywhere across Somerset, follow this routine. - Turn off after you park — level ground, engine stopped, and not in a rush beside Wyndham Way at the roadside. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds daft and it does the trick. - Both under one flap? Then confirm the lid on the diesel filler is still closed before lifting the bottle. - Tip slowly, using the bottle's own spout. Stop when it is full or when the bottle is empty. - Close the cap and check a second time. Make sure your diesel cap was never opened. Only then start the car. Stop there if you find, at step two or three, that you've already poured into the diesel side. Skip step five altogether. ## Portishead: already put AdBlue in your diesel tank? Brief list, then. First: your engine remains off. The fuel pump starts on plenty of diesels as soon as your ignition goes on — and so keep it off. Filling up with diesel will not weaken it: rather than mixing, AdBlue drops to the base of the tank, right where fuel is drawn from. The attendants at Shell, Sainsbury's or another forecourt will usually lend a hand to push the car clear if asked. If you are on your own driveway in Portishead, leave the vehicle where it is. If the motor has already run, stop as soon as it is safe then switch off. Come off the M5 — under 3 miles out of Portishead — at the next exit. Mileage matters — a short hop across Portishead makes a smaller job than driving under 10 miles to Bristol — so say about how far it went. ## What takes place when our engineers get there around Portishead Our technicians come to your car wherever it has stopped, whether that is outside Portishead Primary School, near Compass or on your own drive. We ask what was put in, roughly how much, and whether it's run, since those answers determine this work and our price. During the phone call itself, you hear our price — ahead of dispatch. Then your tank is drained and the system cleaned thoroughly. 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. The filter is cleaned, or replaced where it needs to be; fresh diesel goes in; and the vehicle is tested. Before we leave, our technicians fire it up and make sure that it's running smoothly. Most jobs are done in about half an hour once our engineers get there, provided your engine has not run — and the pumps we use are fine on a live forecourt and quiet at night outside a house. You pay on the day, with nothing upfront, and get a VAT invoice and an engineer report for your insurer. While we travel, take a look at your insurance documents; plenty include cover for misfuelling. ## About Portishead itself Portishead is a coastal town in Somerset, situated on the Bristol Channel at an elevation of around 10 metres. Portishead lies close to the city of Bristol, approximately 7.5 miles away, and is surrounded by nearby hills such as Dry Hill, Woodhill, and West Hill. Portishead has a population of around 20,121 people and is characterised by predominantly detached housing. Portishead is also located about 113.6 miles west of London. ## AdBlue drains about Portishead, and Somerset beyond Portishead is a coastal town, and our vans that cover it also work the towns around it, Woodhill and West Hill among them, across the BS postcode area. Our van gets to you fastest with a postcode starting BS20 6. Your car stays where it is. Draining takes place on the spot, whether a driveway, a street near Portishead Millstone, or a lay-by on the way to Rodmoor Rose Gardens. Ring and ask rather than assuming if you're near a boundary, or somewhere hard to explain, like the back of The Beacon Hub. ## In short, for Portishead motorists Tip nothing till you have read the cap. Petrol in Diesel empties it where it stands, anywhere in Somerset, if AdBlue has gone in the diesel tank regardless — and so leave it off then call 0333 366 0103.