--- title: AdBlue in a Diesel Tank Pendoylan: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/pendoylan-the-vale-of-glamorgan/ location: Pendoylan county: The Vale of Glamorgan latitude: 51.480330 longitude: -3.355130 service: AdBlue in a Diesel Tank updated: 2026-10-10 --- # AdBlue in a Diesel Tank in Pendoylan: Why It Happens and How to Stop It If AdBlue is already in your diesel tank, stop reading for a moment: leave the motor and the ignition off then call 0333 366 0103. In Pendoylan, finding it before your motor runs normally leaves a drain and a thorough flush where it stands. Nothing happened yet? Below, the rest of the page explains the reasons it happens and the ways to prevent it for good. ## Two fillers, two tanks: AdBlue in a diesel car Diesel feeds your engine — yet plenty of current diesels seen around Pendoylan and Peterston-super-Ely hold another liquid as well. AdBlue goes to the exhaust, where it is sprayed into the gas to fresh it, and it lives in a tank of its own. Different tanks, different fillers. On a lot of motors the two sit side by side under the same flap; on others the AdBlue filler is in your boot or under the bonnet. Diesel gets filled on each filling station visit, again and again. Seldom filled, AdBlue usually goes in out of a bottle, poured by someone who must stop and think which filler to use. The mistake grows in the gap between the two. ## AdBlue in the diesel tank in Pendoylan: how it takes place Three things tend to line up, and carelessness is seldom one of them. The warning comes first. As AdBlue runs low your car tells you, and if it runs out altogether, the vehicle goes into limp mode. So the top-up is done in a hurry: on a drive off Heol St Cattwg before work, or in the car park at The Red Lion at Pendoylan on the way home. Then the vehicle is new. A hire car, a new motor or a company car puts the fillers where your last one didn't, and your hand hits 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, and so nothing stops the pour after it has started. Tre-Dodridge or the middle of Pendoylan: it is the same few seconds either way. ## Which filler is for AdBlue, and which for diesel? Check these before pouring, at a forecourt in Pendoylan or a drive out in Wyndham Park. Seconds, that's all. - Blue and lettering: an AdBlue cap is regularly blue, or says "AdBlue", where a diesel cap normally doesn't. Trust the cap, not its position. - Plenty of cars give AdBlue the smaller neck of the two. - A label inside your fuel flap frequently says which fuel goes where, on many vehicles. Check for it. - The handbook. If your filler isn't by the diesel cap, it's in the boot or under the bonnet, and the handbook says which. - Picking up a hire or company car, say at the car park at Pontyclun? Check with the person who drove the vehicle last before leaving, not when the light goes on. ## How to top up without AdBlue in the diesel tank Wherever across The Vale of Glamorgan the light comes on, here is a routine for the day. - Park then switch off. Not on a slope, not with your engine running, and not in a rush on the side of Heol Ty Mawr. - Silly as it sounds, speaking "AdBlue" out loud while you unscrew the cap does the trick — after you've located your filler and read it. - If both sit under one flap, check your diesel cap is still closed before you lift the bottle — then leave the car on. - Gently is best, through the bottle's own spout, till it is full or the bottle is empty. - Close the cap, and check once more — confirm the diesel cap remained closed throughout. After that, start the car. Stop there if you find, at step two or three, that you have already poured into your diesel side. Leave out step five altogether. ## AdBlue in your diesel tank already, around Pendoylan? Then the order of things is short. Do not start your engine. Leave your ignition off too, because on many diesels switching it on by itself runs your pump. Topping up with diesel will not thin it: rather than mixing, AdBlue sinks to the base of the tank, right where fuel is taken from. At a forecourt — BP, Murco or another — the staff will usually help push the vehicle away, when you ask. Leave it where it is if you are on your own driveway around Pendoylan. Stop as soon as it is safe and switch off, if the motor has already run. The next exit is where to come off when you are on the M4, under 3 miles from Pendoylan. Distance counts — a short hop across Pendoylan is a smaller job than heading under 10 miles towards Cardiff — so tell us about how far it went. ## What occurs when we get there in Pendoylan We come to your car wherever it has stopped, whether that is outside the local primary school, close to Pendoylan War Memorial Hall or on your own driveway. What fluid went in, the quantity, and whether it ran: we ask since those replies decide both work and quote. No one heads out before you have had the price over the phone. The fuel system is then flushed thoroughly, once that tank is emptied. Unlike petrol, AdBlue leaves crystals and eats at certain fuel-system metals, and neither clears out unaided. That is why it matters more. Once your filter is cleaned — or renewed, if needed — clean diesel is added, and finally the car is tested. Then we start it and confirm it runs smoothly before we go. Most jobs are finished in about half an hour once our engineers get there, as long as the motor hasn't run — and the pumps our technicians use are safe on a busy forecourt and quiet after dark beside a house. The insurer will ask for the engineer's report and the VAT invoice, and you get both at the end. Payment is on the day, with no deposit. Before we get there, have a look at your policy; many carry cover for misfuelling. ## About Pendoylan itself Pendoylan is a small village situated on the banks of a river in the Vale of Glamorgan, with an elevation of around 50 metres. Pendoylan lies close to the nearby villages of Tre-Dodridge, Clawdd-coch, and Gwern-y-Steeple, and is approximately 7.7 miles from Cardiff. Pendoylan has a population of around 517 people, predominantly living in detached houses. Pendoylan is located in a rural area, with Cardiff to the east and the Welsh countryside to the west. ## AdBlue drains around Pendoylan, and The Vale of Glamorgan beyond Pendoylan is a village, and our teams that cover it also work the towns around it, Clawdd-coch and Gwern-y-Steeple among them, across the CF postcode area. A postcode starting CF71 7 gets our van to you fastest. Moving the car isn't needed. Draining happens right there, be it a drive, a street by Peterston Village Hall, or a lay-by towards Coed Cadw. If you are close to a border, or somewhere hard to describe like the back of St Peter's Church, ring and ask rather than guessing. ## For Pendoylan people, the short version First, the cap; then, the pour. AdBlue in your diesel tank regardless? Keep the car off then ring 0333 366 0103; Petrol in Diesel empties it on the spot, across The Vale of Glamorgan.