--- title: AdBlue in a Diesel Tank Hendredenny? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/hendredenny-caerphilly/ location: Hendredenny county: Caerphilly latitude: 51.579100 longitude: -3.250490 service: AdBlue in a Diesel Tank updated: 2026-10-06 --- # Hendredenny: How Does AdBlue End Up in a Diesel Tank, and How Do You Prevent It? Keep the engine and ignition off then ring 0333 366 0103 now — reading can wait if AdBlue is already in your diesel tank. A drain and a thorough flush, done just where the vehicle stands in Hendredenny, is usually what it takes when found before the engine runs. The rest of this page covers why it happens and how to ensure it does not — useful if you are reading ahead of time. ## Why does AdBlue in a diesel car need its own filler? Many modern diesels on the roads about Hendredenny and Penyrheol carry two liquids, not one. Diesel goes to your engine. Kept in a tank of its own, AdBlue is sprayed into the exhaust gas and cleans it. Different tanks, separate fillers. Under one flap, next to each other: that is the arrangement on a lot of cars. On others, AdBlue's filler sits under the bonnet or in the boot instead. At the pump, the diesel side is topped up all the time. The AdBlue side is filled far less frequently, usually from a bottle, and usually by someone who has to stop and think where it goes. The mistake grows in the gap between them. ## Hendredenny: how AdBlue in your diesel tank happens Rarely is it carelessness: normally three things coincide. First, the warning. Low AdBlue brings a message from your car, and letting it run dry leads to limp mode — hence a rushed top-up, perhaps before work off Eglwysilian Road, perhaps outside White Cross Inn on the way home after work. Then, your hand goes for the cap it knew on the old vehicle — because a hire car, a new vehicle or a company car puts the fillers somewhere your last one did not. Third, the spout goes in: a diesel filler or AdBlue one, it goes in just as readily, and once the pour begins, nothing halts it. Hendredenny Park or the middle of Hendredenny: it is the same few seconds in both. ## The AdBlue filler and the diesel filler: telling them apart Whether a Hendredenny forecourt or a drive out in Watford Park, take a couple of seconds on these before any is poured in. - Read the cap instead of going by position: AdBlue caps are commonly blue or marked "AdBlue", and diesel ones normally aren't. - Many vehicles fit AdBlue the smaller neck of the two. - A label inside your fuel flap often shows which fuel goes where, on plenty of motors. Check for it. - The handbook. If the filler is not by your diesel cap, it is in your boot or under the bonnet, and the handbook says which. - The previous driver knows. Ask as you collect a hire car or fleet car — at Aber's car park, say — not when the warning comes on. ## AdBlue top-ups that never reach the diesel tank On the day the light appears — wherever it is across Caerphilly — a simple routine to follow. - Not in a rush on the side of Groeswen Road, not on a slope, not with the engine running: park and switch off first. - Say "AdBlue" out loud as you unscrew the cap, once finding the AdBlue filler and reading it. Daft, yes, but it does the trick. - If both sit under one flap, check the diesel cap is still closed before you lift the bottle — and leave the car on. - Pour slowly, using the bottle's own spout. Stop when it's full or when the bottle is empty. - Before starting the car, close the cap and check a second time that the diesel cap was never came off. Find during the second or third step that the bottle went into the diesel tank? That's where you stop. Leave out stage five altogether. ## AdBlue in the diesel tank already, in Hendredenny? What follows is a short order of things, beginning with not starting your engine. On plenty of diesels your ignition alone runs the fuel pump, and so don't switch it on. Don't top up with diesel to dilute it: AdBlue doesn't mix with diesel, it sinks to the bottom of the tank, where your fuel is sucked from. If you're at a forecourt, whether it's the Texaco or the BP, ask the staff to help push the vehicle clear of the petrol pump. At home around Hendredenny? So your car stays where it is. When the engine has been run already, stop safely then switch it off. The next junction is where to come off if you're on the M4, under 5 miles from Hendredenny. Tell us about how far it went: a run towards Cardiff, under 10 miles away, is a bigger job than a short hop across Hendredenny. ## Hendredenny: what occurs when our technicians turn up Our technicians come to your car wherever it has stopped, whether that's outside the local primary school, close to Groeswen Chapel or on your own drive. What fluid got in, the quantity, and whether it ran: our engineers ask because the answers decide both work and quote. You hear that price on the phone, before anybody heads out. After that: a drain, then a full flush of the whole system. AdBlue crystallises and is corrosive to some of the metals in a fuel system, and so it doesn't wash out on its own — which is why that counts more here than with petrol. Filter flushed or, if it must be, swapped; clean diesel in; and then a check of the car. Before we go, our engineers start the engine and make sure that it's running properly. If the motor has not run, most 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 at night. The insurer usually wants an engineer's report and your VAT invoice, and both are yours once the job is done. Payment is on the day, with no money upfront. Plenty of insurance policies include misfuelling cover, so it is worth checking yours while we are on the way. ## About Hendredenny, for a moment Hendredenny is a suburban area in Caerphilly, situated near the riverside and approximately 159 metres above sea level. Hendredenny lies close to Cardiff, the capital city of Wales, and is surrounded by nearby places such as Hendredenny Park and the Glenfield Estate. Hendredenny has a population of around 2757 people and predominantly features semi-detached housing. Hendredenny is located about 7.5 miles from Cardiff city centre, making it a commuter-friendly area. ## AdBlue drains in Hendredenny and across Caerphilly Hendredenny is a residential suburb, and the teams that cover it also work the towns around it, Glenfield Estate and Trecenydd among them, across the CF postcode area. Quickest of all: quote a CF83 2 postcode to our van. The vehicle stays put. Our technicians drain it where it is — a side street close to The Meadows Wildlife Park, a lay-by on the way to Aneurin Park, a drive. Guessing won't help behind St Andrew's Church, close to a boundary, or anywhere hard to describe; phone and ask. ## For Hendredenny motorists, the short version Before you tip, read the cap. If AdBlue has gone in your diesel tank anyway, leave the vehicle off and phone 0333 366 0103. Petrol in Diesel clears it where it waits, anywhere in Caerphilly.