--- title: AdBlue in a Diesel Tank Pennar: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/pennar-pembrokeshire/ location: Pennar county: Pembrokeshire latitude: 51.685890 longitude: -4.955830 service: AdBlue in a Diesel Tank updated: 2026-10-26 --- # Avoiding AdBlue in a Diesel Tank in Pennar: Why It Happens If AdBlue is already in your diesel tank, stop reading for a moment: leave your motor and your ignition off and call 0333 366 0103. In Pennar, finding it before the engine runs usually leaves a drain and a full flush on the spot. If you're reading before it has happened, the rest of this page is about why it occurs and how to make sure it doesn't. ## AdBlue in a diesel car: two tanks, two fillers Diesel feeds your engine — but plenty of newer diesels seen about Pennar and Pembroke Dock carry another liquid too. AdBlue goes to your exhaust, where it is sprayed into the gas to fresh it, and it lives in a tank of its own. Separate tanks, different fillers. Plenty of motors have a single flap for both, while some move the AdBlue filler to the boot or under the bonnet. Diesel goes in on every filling station visit, again and again. Far less commonly, the AdBlue side is topped up — mostly from a bottle, by a person thinking about where it goes. The mistake grows in the gap between the two. ## Pennar: how AdBlue in your diesel tank takes place It is seldom carelessness. Three things tend to line up. The warning comes first. As AdBlue runs low the vehicle tells you, and if it runs out completely, your vehicle drops into limp mode. So the top-up is done in a hurry: on a drive off Stranraer Lane before work, or in the car park at Charlton on the way home. Then the car is strange. A hire car, a new car or a company car puts the fillers where your last one didn't, and the hand hits for the cap it would have used on the old one. A spout-topped bottle meets no resistance at a diesel filler any more than at an AdBlue one. And so the pour, after begun, carries on. Whether it takes place in Llanreath or the middle of Pennar, it is the same few seconds. ## The AdBlue filler and your diesel filler: telling them apart Look at these first, at a forecourt around Pennar or a drive out in Llanion. Seconds, no more. - Read the cap rather than going by position: AdBlue ones are commonly blue or marked "AdBlue", and diesel ones usually are not. - On plenty of vehicles, size tells: AdBlue has the smaller filler neck. - A label inside the fuel flap frequently shows which fuel goes where, on many motors. Look for it. - Can't see it next to your diesel filler? Then look beneath the bonnet or in your boot — the handbook will say which. - Whoever had it before will know. Ask as you pick up a rental or company car — from Pembroke Dock's car park, perhaps — rather than when the light appears. ## How to top up without AdBlue in your diesel tank For the day the light comes on — wherever you are in Pembrokeshire — a routine to use. - Not in a rush on the side of Military Road, not on a slope, not with your engine running: park and switch off properly. - Say "AdBlue" out loud as you unscrew the cap, after finding the AdBlue filler and reading it. Silly, yes, but it does the trick. - Both under a single flap? Then make sure the lid on your diesel side stays closed before lifting the bottle. - Stop once that tank fills or the bottle is empty; before that, tip gently using the own spout. - Only then, start your car: close the cap, check again, and make sure your diesel cap was never opened. Find at stage two or three that it's already gone into your diesel side? Then stop right there. Stage five stays out. ## AdBlue in the diesel tank already, around Pennar? Do not start your motor: that's where the short order of things begins. Leave your ignition off as well, because on many diesels it by itself runs the pump. Topping up with diesel will not thin it: instead, AdBlue sinks to the bottom of the tank, just where fuel is drawn from. If you're at a forecourt, whether it's the Asda or the Tesco, ask the attendants to help push your car away from the pump. If you are on your own driveway around Pennar, leave it where it sits. Already run? Pull over once it is sensible, then turn off. On the M4, under 50 miles from Pennar, that means the next exit. Roughly how far did it go? Crossing Pennar is less work than a run of under 25 miles to St Davids, and so tell us. ## Our arrival in Pennar, and what occurs next Wherever your car came to rest, whether outside the local primary school, beside Defensible Barracks or at home, the van comes to it. We ask what went in, roughly how much, and if it has run, since the replies settle this work and the quote. Nobody sets off until you've heard our price by phone. Emptying the tank comes next, then a full flush of your system. More than with petrol, it matters with AdBlue: crystals form, certain metals are attacked, and nothing clears away unaided, however long it sits. The filter flushed or, where it must be, replaced; clean diesel in; then a check of the car. After that we fire it up and confirm it runs correctly before we leave. If the engine has not run, most jobs take about half an hour once we're there, using pumps that are safe on a busy forecourt and quiet enough to use outside a house 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's worth checking yours whilst we are on the way. ## About Pennar itself Pennar is a coastal suburban area in Pembrokeshire, situated near the coast at an elevation of 56 metres. Pennar lies within commuting distance of St Davids, the smallest city in the UK, and is close to nearby places such as Llanreath and Pennar Park. Pennar has a population of around 2044 people, predominantly living in semi-detached housing. Pennar is located approximately 207.6 miles west of London, in the scenic coastal region of southwest Wales. ## AdBlue drains across Pembrokeshire, Pennar included Throughout SA postcodes, our teams covering Pennar — a residential suburb — work the surrounding places too, Bentlass and Pennar Park among them. Quickest of all: give a SA72 6 postcode to our van. Shifting your car isn't necessary. The drain happens on the spot, whether a driveway, a street by Pembroke Dock Heritage Centre, or a lay-by towards South Pembrokeshire Golf Club. Tricky to explain, like the back of VC Gallery? Close to a border? Checking beats guessing, and so ring. ## Pennar drivers: the short version Always, the cap; after that, the pour. AdBlue in your diesel tank regardless? Keep the vehicle off then phone 0333 366 0103; Petrol in Diesel empties it on the spot, throughout Pembrokeshire.