--- title: AdBlue in a Diesel Tank Hook: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/hook-pembrokeshire/ location: Hook county: Pembrokeshire latitude: 51.763110 longitude: -4.930660 service: AdBlue in a Diesel Tank updated: 2026-10-15 --- # Why It Happens and How to Prevent It: AdBlue in a Diesel Tank in Hook AdBlue already in the diesel tank? In that case set this page aside for now, leave the ignition and motor off, then call 0333 366 0103. A drain and a thorough flush, done just where the vehicle stands in Hook, is usually all it needs when caught before the motor runs. Here in advance? In that case what follows explains why it happens and how to stop it happening at all. ## Why does AdBlue in a diesel motor need its own filler? Many newer diesels in Boulston, like those in Hook, carry on two liquids; the engine gets just the diesel. Its own tank keeps it, and from there it goes to the exhaust, and there a spray cleans the gas. There's a filler for each tank. Some vehicles keep the AdBlue filler in the boot or under the bonnet; a lot more have both side by side under one flap. The diesel side is filled at the pump all the time. Rarely topped up, AdBlue normally comes out of a bottle, poured by someone who has to stop and think which filler it needs. That gap is where the slip lives. ## Hook: how AdBlue in your diesel tank happens Seldom is it carelessness: usually three things line up. Hurry comes from the warning. The car tells you as AdBlue runs low, and a dry tank sends the vehicle into limp mode — so the top-up gets done in a rush, before work on a driveway off Pill Road, or heading home in the car park at the pub in the village. Then your car is new. A hire car, a new vehicle or a company car puts the fillers where your last one didn't, and your hand reaches for the cap it would have used on the old one. A spouted bottle finds no resistance at a diesel filler no more than at an AdBlue one. And so the pour, after started, carries on. It takes a few seconds, be it out in Deerland or bang in the heart of Hook. ## How to tell the AdBlue filler from the diesel one Before you pour anything, whether on a drive in Guilford or a forecourt around Hook, check these. They take a couple of seconds. - The cap. The AdBlue cap is frequently blue, or marked "AdBlue". Your diesel cap normally isn't. Read it rather than going by position. - Plenty of vehicles give AdBlue the smaller filler of the two. - A label inside your fuel flap frequently shows which fuel goes where, on many cars. Look for it. - In the boot or under the bonnet: that's where your filler sits if it is not by your diesel cap, and the handbook tells you which. - Collecting a hire or company car, say at the car park at Johnston? Ask the person who drove the vehicle last before you set off, rather than once the light goes on. ## Topping up AdBlue without it reaching the diesel tank On the day the warning comes on — wherever it is in Pembrokeshire — a routine to follow. - Park then switch off. Not on a slope, not with your motor running, and not in a rush on the side of West Hook Road. - Say "AdBlue" out loud as you unscrew the cap, once you find the AdBlue filler and reading it. Daft, perhaps, yet it works. - The two under one flap? Then make sure the lid on the diesel filler is still shut ahead of raising the bottle. - Gently is best, through the bottle's own spout, until it is full or the bottle is empty. - Shut the cap, then look again — confirm your diesel cap stayed shut throughout. Only then, start the vehicle. If at step two or three you find you have already poured into your diesel side, stop there. Do not go on to step five. ## Hook: already put AdBlue in the diesel tank? Then the order of things is short. Do not start your engine. Leave the ignition off as well, since on plenty of diesels it by itself runs the fuel pump. Do not top up with diesel to dilute it: AdBlue does not mix with diesel, it sinks to the bottom of the tank, where the fuel is sucked from. If you are at a forecourt, whether it is the BP or the Tesco, ask the attendants to help push the car away from the pump. Leave it where it is if you're on your own drive in Hook. If the motor has already run, stop as soon as it is safe and switch off. Come off the M4 — under 50 miles out of Hook — at the first exit. Distance matters — a short hop across Hook makes a smaller job than driving under 25 miles to St Davids — so say about how far it went. ## Our arrival in Hook, and what occurs next We come to the car wherever it has stopped, whether that is outside the local primary school, close to Boulston Church (remains of) or on your own driveway. Those answers determine the work and our quote, and so our technicians ask what went in, about how much, and if it's run. No one sets off before you've heard our price by phone. Your system is then cleaned thoroughly, after your tank is cleared. AdBlue crystallises and is corrosive to some of the metals in a fuel system, and so it does not wash out on its own — which is why the flush matters more with AdBlue than with petrol. Testing is last: before that, clean diesel goes in, and the filter is cleaned or replaced as needed. Next we start the car and make sure it runs smoothly before we leave. If the engine hasn't run, the majority of jobs take about half an hour once we are there, using pumps that are fine on a working forecourt and quiet enough to use outside a house after dark. Your insurer usually wants the engineer's report and your VAT invoice, and you get both at the end. Payment is on the day, with no deposit. Before we get there, take a look at your policy; many include cover for misfuelling. ## About Hook itself Hook is a coastal village in Pembrokeshire, situated at an elevation of 41 metres, with detached housing being the predominant type of accommodation. Hook sits near the villages of Deerland and Little Milford, and is close to the scenic area of Maddox Moor. Hook is located approximately 16 miles from St Davids, the smallest city in the UK. Hook has a population of around 886 residents, who enjoy the village's coastal setting. ## AdBlue drains round Hook, and Pembrokeshire beyond Over SA postcodes, our teams that cover Hook — a coastal village — work the nearby locations too, Maddox Moor and Little Milford among them. Quickest of all: quote a SA62 4 postcode to our van. The car stays where it is. Our technicians drain it where it is — a side street close to Manor House (Remains of), a lay-by on the way to Mayfieild Golf Centre, a drive. If you're close to a border, or somewhere hard to describe like the back of Freystrop Village Hall, ring and ask instead of guessing. ## For Hook drivers, the short version Read the cap before you pour. Still AdBlue in the diesel tank? Petrol in Diesel will drain it wherever it stands, wherever in Pembrokeshire: keep it off and ring 0333 366 0103.