--- title: AdBlue in a Diesel Tank Rhiwbina: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/rhiwbina-cardiff/ location: Rhiwbina county: Cardiff latitude: 51.528400 longitude: -3.213290 service: AdBlue in a Diesel Tank updated: 2026-10-09 --- # AdBlue in a Diesel Tank in Rhiwbina: How It Happens and How to Prevent It If AdBlue is already in your diesel tank, stop reading for a moment: leave the motor and the ignition off then phone 0333 366 0103. Caught before the motor runs, it's normally a drain and a thorough flush, done where the vehicle is around Rhiwbina. The remainder of this page explains why it takes place and how to ensure it does not — handy if you are reading before it has happened. ## Two fillers, two tanks: AdBlue in a diesel vehicle No single liquid but two: that is what plenty of newer diesels near Rhiwbina and Whitchurch run, with diesel feeding your engine. Kept in a tank of its own, AdBlue is sprayed into your exhaust gas to clean it. Each tank has one filler of its own. Other vehicles keep the AdBlue filler in the boot or under the bonnet; plenty of others place the two together behind one flap. The diesel side is fuelled at the petrol pump all the time. The AdBlue side is filled far less regularly, usually from a bottle, and normally by someone who has to stop and think where it goes. Mistakes happen in that gap between the two. ## How AdBlue in your diesel tank occurs in Rhiwbina Rarely is it carelessness: normally three things coincide. The warning comes first. As AdBlue runs low your car tells you, and if it runs out altogether, the vehicle drops into limp mode. So the top-up is done in a hurry: on a drive off Heol Nant Castan before work, or in the car park at The Deri on the way home. Unfamiliar vehicles come next, too. Hire cars, new vehicles and company motors put their fillers differently, and habit goes for the cap 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 once it has started. The same few seconds settle it, in the middle of Rhiwbina or out in Pantmawr. ## Which filler is for AdBlue, and which for diesel? Whether a Rhiwbina forecourt or a drive over in Birchgrove, take a few seconds over these before any is poured in. - Position misleads; the cap does not. AdBlue ones tend to be blue or bear the word "AdBlue" — diesel caps normally do not. - Check the size: the smaller neck is, on plenty of cars, the AdBlue one. - Lift the filler flap and look for a label — many motors show which belongs in which filler just there. - The handbook. If your filler is not by your diesel cap, it's in your boot or under the bonnet, and the handbook says which. - The previous driver knows. Check when you collect a hire car or company car — at the nearest station's car park, say — rather than when the warning appears. ## AdBlue top-ups that never reach the diesel tank Anywhere in Cardiff the light comes on, this is a routine for that day. - Park and switch off. Not on a slope, not with the motor running, and not in a rush on the side of Heol Llanishen Fach. - Find the AdBlue filler, check the cap, and speak the word "AdBlue" out loud as you unscrew it. It seems silly. It works. - If both sit under one flap, check your diesel cap is still closed before you lift the bottle — and leave the car on. - Gently is best, through the bottle's own spout, until it is full or the bottle is empty. - Only after that, start your car: close the cap, check again, and make sure your diesel cap was never opened. If at stage two or three you find you have already poured into your diesel side, stop there. Don't go on to stage five. ## Already put AdBlue in your diesel tank in Rhiwbina? Don't start the engine: that is how the short order of things starts. Keep your ignition off as well, since on plenty of diesels switching it on by itself starts your pump. Don't top up with diesel to dilute it: AdBlue doesn't mix with diesel, it sinks to the bottom of the tank, where the fuel is drawn from. If you are at a forecourt, whether it is the Morrisons or the Tesco, ask the attendants to help roll the car clear of the petrol pump. Your own drive around Rhiwbina is where it should stay. Already run? Stop once it is safe, then switch off. The next exit is the place to leave when you are on the M4, under a mile from Rhiwbina. Tell us roughly how far it went: a run towards Cardiff, under 5 miles away, is a bigger job than a short hop across Rhiwbina. ## What takes place when our engineers arrive in Rhiwbina Outside the local primary school, close to Bethany Baptist Church or on your own drive: wherever the car has stopped, we come to it. The answers settle this work and our quote, so our engineers ask what got in, roughly how much, and whether it has run. During the phone call itself, you hear the price — before anything else. The fuel system is then cleaned thoroughly, after the tank is cleared. With AdBlue that matters more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, and so it does not wash out on its own. The filter flushed or, where it must be, swapped; fresh diesel in; and then a test of your vehicle. We don't leave until it has been started and is running smoothly. Unrun cars mostly mean a half-hour visit after arrival. The equipment is fine on a busy filling station, and quiet enough for a driveway after dark. You pay on the day, with nothing upfront, and get a VAT invoice and an engineer report for your insurer. Many insurance policies include misfuelling cover, so it is worth checking yours whilst we are on the way. ## About Rhiwbina Rhiwbina is a suburban area in Cardiff, situated near the River Taff and characterised by its semi-detached housing stock. Rhiwbina sits at an elevation of 52 metres, with nearby neighbourhoods including Pantmawr, Wenallt, and Coryton. Rhiwbina is located approximately 3.7 miles from Cardiff city centre, making it a popular residential choice. Rhiwbina has a population of around 6791 people, according to recent estimates. ## AdBlue drains around Rhiwbina and across Cardiff Throughout CF postcodes, our vans covering Rhiwbina — a residential suburb — work the nearby locations too, Coryton and Wenallt among them. A postcode starting CF14 6 gets our van to you fastest. The car stays where it is. Draining happens on the spot, be it a drive, a street near The Church of Jesus Christ of Latter-day Saints, or a lay-by towards Parc Y Pentre. Tricky to explain, like the back of All Saints’ Church? By a border? Checking is better than guessing, so phone. ## For Rhiwbina people, the short version Before you pour, read the cap. AdBlue in your diesel tank regardless? Leave it switched off then ring 0333 366 0103; Petrol in Diesel empties it on the spot, across Cardiff.