--- title: Caxton: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/caxton-cambridgeshire/ location: Caxton county: Cambridgeshire latitude: 52.209230 longitude: -0.094230 service: AdBlue in a Diesel Tank updated: 2026-10-19 --- # AdBlue in a Diesel Tank in Caxton: Why It Happens and How to Stop It Pause here for a moment when the diesel tank already has AdBlue in it: ignition off, motor off, and phone 0333 366 0103. Caught before your motor runs, it's normally a drain and a thorough flush, done where the vehicle is around Caxton. If you are reading before it has happened, the rest of this page is about why it takes place and how to make sure it doesn't. ## AdBlue in a diesel vehicle, and its separate tank Plenty of newer diesels on the roads about Caxton and Crow End carry two liquids, not one. Diesel goes to the engine. AdBlue goes to the 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. Under one flap, side by side: that's the layout on many cars. On others, AdBlue's filler sits beneath the bonnet or in your boot instead. Diesel gets filled on each forecourt visit, week in, week out. Rarely topped up, AdBlue normally goes in out of a bottle, poured by someone who has to stop and think which filler it needs. It's in the gap that the mistake lives. ## How AdBlue in the diesel tank occurs around Caxton It's hardly ever carelessness. Three things tend to line up. On a driveway off Rosemary Greene Close before work, or in the car park at the pub in the village heading home: that is where the hurried top-up happens. What is the reason for the rush? As AdBlue runs low the car tells you, and once it is empty, limp mode follows. Then the vehicle is unfamiliar. A hire car, a new car or a company car puts the fillers where your last one didn't, and your hand gets to 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. It takes seconds, be it in West Cambourne or right in the centre of Caxton. ## How to tell the AdBlue filler from the diesel one Whether a Caxton forecourt or a drive out in Upper Cambourne, spend a few seconds on these before anything goes in. - Read the cap rather than going by where it sits: AdBlue ones are often blue or marked "AdBlue", and diesel ones normally are not. - The size. On many vehicles the AdBlue filler neck is the smaller of the two. - The flap. Look inside your fuel flap for a label. Many motors say there which fuel goes where. - The handbook says which it is if your filler is not next to the diesel cap: the boot, or under the bonnet. - Whoever had it before knows. Check when you collect a rental or fleet car — at St Neots's car park, perhaps — not once the warning appears. ## Topping up AdBlue without it reaching your diesel tank A routine for the day the light comes on, wherever in Cambridgeshire that is. - Park then switch off. Not on a slope, not with your engine running, and not in a rush on the side of Ermine Street. - Say "AdBlue" out loud as you unscrew the cap, after you find the AdBlue filler and reading it. Silly, perhaps, but it works. - The two under one flap? Then confirm the lid on the diesel side is still shut before lifting the bottle. - Using the bottle's own spout, pour slowly — and stop when it's full or the bottle is empty. - Close the cap, then look once more — confirm the diesel cap remained shut the whole time. Only then, start the vehicle. If at stage two or three you find you have already poured into the diesel side, stop there. Never carry on to step five. ## Caxton: already put AdBlue in your diesel tank? Do not start the engine: that is where the short order of things begins. On many diesels the ignition alone runs the fuel pump, and so do not switch the vehicle on. AdBlue does not mix with diesel — it sinks to the bottom of that tank, where the fuel is sucked from — so do not top up with diesel to thin it. If you're on a forecourt, whether it is the Morrisons or the Shell, ask the staff to help push the vehicle away from the pump. Leave it where it is if you are on your own driveway around Caxton. If the motor has already run, stop as soon as it is safe and switch off. Come off the M11 — under 10 miles out of Caxton — at the first exit. Distance matters — a quick hop across Caxton is a smaller job than heading under 10 miles to Cambridge — so say about how far it went. ## When our engineers turn up around Caxton, what occurs? Our van comes to your car wherever it stopped — your own driveway, near Caxton Village Hall, or by Monkfield Park Primary School. Which fluid went in, the amount, and whether it ran: our engineers ask since the answers decide both work and price. The quote is given on the call, before any van leaves. Your system is then purged thoroughly, once your tank is drained. Unlike petrol, AdBlue leaves crystals and attacks some fuel-system metals, and neither washes out by itself. That is why it counts more. Once your filter is flushed — or renewed, where needed — clean diesel is added, and finally the vehicle gets tested. Before we leave, our technicians fire it up and check that it's running smoothly. Most jobs are done in roughly half an hour after we get there, provided the engine has not run — and the pumps our technicians use are safe 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 policy; plenty include cover for misfuelling. ## About Caxton and where it is Caxton is a small village in Cambridgeshire, situated on the riverside at an elevation of around 55 metres. Caxton lies near the city of Cambridge, approximately 9 miles to the west, and is also close to the nearby settlements of West Cambourne, Lower Cambourne, and Cambourne. Caxton has a population of around 616 people and is characterised by predominantly detached housing. ## AdBlue drains across Cambridgeshire, Caxton included Lower Cambourne and Cambourne are among the places around Caxton, a village, that the same vans cover, throughout CB postcodes. Fastest of all: give a CB23 3 postcode to our van. The car stays put. Our engineers drain it where it is — a side street close to St Andrew (Caxton Parish Church), a lay-by on the way to Millhill Spinney, a drive. Tricky to pin down, like the back of Caxton Moats? By a border? Asking beats assuming, so ring. ## Caxton motorists: the short version Pour nothing till you've read the cap. Petrol in Diesel drains it where it stands, anywhere in Cambridgeshire, if AdBlue has gone in your diesel tank all the same — so leave the vehicle off and phone 0333 366 0103.