--- title: AdBlue in a Diesel Tank Caerau: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/caerau-bridgend/ location: Caerau county: Bridgend latitude: 51.634420 longitude: -3.657040 service: AdBlue in a Diesel Tank updated: 2026-10-03 --- # Caerau: How Does AdBlue End Up in a Diesel Tank, and How Do You Prevent It? If AdBlue is already in your diesel tank, stop reading for a moment: leave the motor and your ignition off then phone 0333 366 0103. In Caerau, catching it before the engine turns usually leaves a drain and a full flush where it stands. Here in advance? Then what follows explains how it comes about and what to stop it happening at all. ## Two fillers, two tanks: AdBlue in a diesel motor Diesel goes to the motor — yet many current diesels driven around Caerau and Blaencaerau carry a second liquid too. AdBlue goes to the exhaust, where it is sprayed into the gas to clean it, and it lives in a tank of its own. Every tank has one filler of its own. Many of motors share a single flap for both, whereas others put the AdBlue filler to your boot or under the bonnet. At the pump, your diesel side gets filled constantly. The AdBlue side is topped up far less commonly, usually from a bottle, and normally by somebody who has to stop and think where it goes. The mistake grows in that gap between the two. ## How does AdBlue in the diesel tank happen in Caerau? Rarely is it carelessness: normally three things line up. Hurry follows from the warning. The car tells you as AdBlue runs low, and an empty tank puts the vehicle into limp mode — so the top-up gets done in a rush, before work on a driveway off Talana Terrace, or heading home in the car park outside Navigation. Next, the hand goes for the cap it would have used on the old motor — since a rental car, a new motor or a company car puts the fillers where your last one did not. And the bottle fits. A bottle with a spout goes into a diesel filler as easily as an AdBlue one, so nothing stops the tip once it has started. The same few seconds settle it, in the middle of Caerau or out in Dyffryn. ## The AdBlue filler and the diesel filler: telling them apart A few seconds is all these take — so run through them before you tip anything, on a drive in Nantyffyllon or a forecourt in Caerau. - Read the cap rather than going by position: AdBlue caps are commonly blue or marked "AdBlue", and diesel caps normally aren't. - On many vehicles, size tells: AdBlue gets the smaller filler neck. - Open the flap and check for a label — plenty of vehicles mark which belongs in each inlet right there. - The handbook says where it is when your filler isn't next to your diesel cap: the boot, or under the bonnet. - Whoever had it before will know. Check as you pick up a rental or company car — at Maesteg's car park, say — not when the warning appears. ## AdBlue top-ups that never reach the diesel tank When the light comes on, anywhere across Bridgend, follow this routine. - Park and switch off. Not on a slope, not with the engine running, and not in a rush on the side of Dyffryn Road. - Say "AdBlue" out loud as you unscrew the cap, after finding the AdBlue filler and read it. Daft, perhaps, yet it works. - Leave the diesel cap on. If both sit under one flap, check the diesel cap is still closed before you lift the bottle. - Stop when the tank fills or the bottle is empty; before that, tip gently through the own spout. - Shut the cap, and look again — confirm your diesel cap remained closed the whole time. Only then, start your car. Spot at step two or three that it's already gone into the diesel side? Then stop just there. Never go on to stage five. ## Already put AdBlue in your diesel tank around Caerau? What follows is a short order of things, starting with no starting your engine. Leave the ignition off too, since on plenty of diesels it alone starts the pump. Do not top up with diesel to thin it: AdBlue does not mix with diesel, it sinks to the bottom of that tank, where the fuel is sucked from. If you're at a forecourt, whether it is the Oils for Wales or the another forecourt nearby, ask the staff to help roll the car away from the pump. At home around Caerau? So your car stays put. Stop as soon as it is safe then switch off, if the motor has already run. On the M4, under 10 miles from Caerau, that means the next junction. Distance matters — a short hop across Caerau is a smaller job than heading under 15 miles to Swansea — so say about how far it went. ## Our arrival around Caerau, and what happens next Outside the local primary school, near Llynfi BMX or on your own drive: wherever the vehicle has stopped, our technicians come to it. Both the work and our price rest on three answers — which fluid, which amount, and if it's run — so our engineers ask. You get that price by phone, before anybody heads out. Emptying that tank comes next, followed by a full flush of your 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 matters more here than with petrol. Your filter is flushed, or replaced where it needs to be; clean diesel goes in; and the vehicle is tested. We do not go until it has been fired up and is running properly. Unrun cars usually need a half-hour visit after arrival. The equipment is safe on a busy forecourt, and hushed enough for a driveway after dark. Payment happens on the day, not upfront, and you are given the documents an insurer wants: an engineer report and a VAT invoice. While we travel, take a look at your insurance documents; plenty include cover for misfuelling. ## About Caerau and where it is Caerau is a suburban area in Bridgend, situated on the riverside with a mix of terraced housing and other residential properties. Caerau sits at an elevation of 181 metres, overlooking the surrounding countryside. Caerau is located near several nearby places, including Dyffryn, Brynheulog, and Spelter, and is within commuting distance of Swansea, which is 12.2 miles away. Caerau has a population of approximately 3678 people. ## AdBlue drains around Caerau, and Bridgend beyond Throughout CF postcodes, our vans that cover Caerau — a residential suburb — work the surrounding places too, Spelter and Brynheulog among them. Our van gets to you fastest with a postcode starting CF34 0. Moving the vehicle is not necessary. A driveway, a lay-by on the way to Tudor Park, a side street close to Afan Valley Swimming Pool: our engineers drain the vehicle where it sits. Awkward to pin down, like the back of Keeper Of The Collieries? By a county line? Asking is better than assuming, and so ring. ## The short version for Caerau motorists Before you tip, read the cap. If AdBlue has gone in your diesel tank anyway, leave it off then ring 0333 366 0103. Petrol in Diesel empties it where it waits, anywhere around Bridgend.