--- title: AdBlue in a Diesel Tank Longfleet? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/longfleet-dorset/ location: Longfleet county: Dorset latitude: 50.724640 longitude: -1.977580 service: AdBlue in a Diesel Tank updated: 2026-10-21 --- # Why It Happens and How to Avoid It: AdBlue in a Diesel Tank in Longfleet AdBlue already in the diesel tank? In that case put this page aside a moment, leave the ignition and motor off, and call 0333 366 0103. A drain and a thorough flush, carried out right where the car stands around Longfleet, is usually what it takes if found before the engine runs. Not happened yet? Below, the rest of the page explains the reasons it happens and the how to prevent it for good. ## Why does AdBlue in a diesel car need its own filler? Plenty of current diesels on the roads about Longfleet and Stanley Green carry two liquids, not one. Diesel goes to your motor. The exhaust, not your motor, is where AdBlue goes: dosed into the gas to fresh it, from a separate tank. Each tank has a filler of its own. On a lot of vehicles the two sit side by side under the same flap; on others the AdBlue filler is in the boot or under the bonnet. Diesel gets filled at every forecourt visit, week in, week out. Someone who has to stop and think where it goes usually fills the AdBlue side, from a bottle, and much less frequently. It is in that gap that the error happens. ## AdBlue in the diesel tank in Longfleet: how it takes place Carelessness seldom causes it. What does is three things coming up together. First, the warning. Low AdBlue triggers a message from your car, and running out means limp mode — hence a hurried top-up, maybe before work off Saint Margaret's Road, or at George Hotel on the way home that evening. Then your car is strange. A hire car, a new motor or a company car puts the fillers where your last one did not, and your hand reaches for the cap it would have used on the old one. 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. Sterte or the heart of Longfleet: it is the same few seconds either way. ## The AdBlue filler and your diesel filler: telling them apart Whether a Longfleet forecourt or a driveway out in Old Town, take a few seconds on these before any goes in. - Blue and lettering: an AdBlue cap is frequently blue, or says "AdBlue", where a diesel cap usually doesn't. Trust the cap, not its position. - The size. On many cars the AdBlue filler neck is the smaller of the two. - A label inside your fuel flap frequently shows which fuel goes where, on many motors. Look for it. - In the boot or under the bonnet: that is where the filler is if it is not by your diesel cap, and the handbook tells you which. - The person who drove the vehicle last. On a hire or company car collected from somewhere like the car park outside Poole, ask before you leave, not when the light comes on. ## Keeping AdBlue out of your diesel tank when you top up On the day the light comes on — anywhere you are in Dorset — a routine to follow. - Stop on level, motor off, with time in hand — not hurried on the side of Garland Road. - Say "AdBlue" out loud as you unscrew the cap, after finding the AdBlue filler and read it. Silly, perhaps, yet it does the trick. - The diesel cap stays on. When both share a flap, confirm it's closed before lifting the bottle. - Using the bottle's own spout, pour slowly — and stop when it is full or the bottle is empty. - Shut the cap, then check once more — making sure your diesel filler stayed closed throughout. Only then, start the car. If at step two or three you find you have already poured into your diesel side, stop there. Never go on to stage five. ## Put AdBlue in your diesel tank in Longfleet already? The short order of things, beginning with not starting the motor. Leave your ignition off as well, because on plenty of diesels switching it on by itself starts the fuel pump. Thinning it with more diesel fails, since AdBlue sinks to the bottom instead of blending — and that is where your fuel is sucked from. Ask the staff to help push your car away from the petrol pump if you are on a forecourt — the BP, the Esso or somewhere else. If you're on your own drive around Longfleet, leave the car where it sits. If the motor has already run, stop as soon as it is safe and switch off. On the M27, under 25 miles from Longfleet, that means the next exit. Tell us about how far it went: a run towards Salisbury, under 50 miles away, is a bigger job than a short hop across Longfleet. ## Our arrival in Longfleet, and what occurs next The van comes to the car wherever it has come to rest — your own driveway, beside Longfleet Baptist Church, or outside Longfleet Church of England Primary School. Those replies decide this work and the quote, so we ask what went in, about how much, and whether it's run. No one sets off before you have heard our quote by phone. The system is then cleaned thoroughly, once that tank is cleared. Not like petrol, AdBlue leaves crystals and eats at certain fuel-system metals, and neither clears out unaided. Hence it counts more. After your filter is flushed — or renewed, where needed — clean diesel is added, and then the car is tested. We don't leave until it has been fired up and is running properly. With pumps fine on a busy forecourt and quiet enough to use outside a house at night, most jobs where the engine has not run take about half an hour once our engineers arrive. The insurer will ask for an engineer's report and your VAT invoice, and you get both at the end. Payment is on the day, with no money upfront. Plenty of insurance policies include misfuelling cover, and so it is worth checking yours while we are on the way. ## About Longfleet itself Longfleet is a coastal suburban area in Dorset, situated near the towns of Poole and Oakdale, with Sterte to the west. Longfleet lies at a low elevation of around 16 metres above sea level, close to the shores of Poole Harbour. Longfleet has a population of approximately 6498 people, predominantly residing in flat-type housing. Longfleet is also within commuting distance of larger cities like Salisbury, which is around 25 miles away. ## AdBlue drains about Longfleet, and Dorset beyond Poole and Oakdale are among the places near Longfleet, a residential suburb, that the same vans cover, over BH postcodes. A postcode starting BH15 2 gets the van to you fastest. Your car stays where it is. The drain happens right there, be it a driveway, a street by Brethren Meeting Hall, or a layby on the way to Sterte Green. If you're near a border, or somewhere hard to describe like the back of Friends Meeting House, ring and ask instead of assuming. ## The short version for Longfleet drivers First, the cap; after that, the tip. Petrol in Diesel empties it on the spot, anywhere across Dorset, if AdBlue has gone in your diesel tank anyway — so leave the vehicle off then call 0333 366 0103.