--- title: AdBlue in a Diesel Tank Steynton: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/steynton-pembrokeshire/ location: Steynton county: Pembrokeshire latitude: 51.729600 longitude: -5.016040 service: AdBlue in a Diesel Tank updated: 2026-10-25 --- # AdBlue in a Diesel Tank in Steynton: Why It Happens and How to Prevent It If AdBlue is already in your diesel tank, stop reading for a moment: leave the motor and your ignition off and phone 0333 366 0103. A drain and a full flush, carried out just where the car stands in Steynton, is usually all it needs if caught before your motor runs. Reading in advance? Then what follows explains how it comes about and what to stop it happening at all. ## Why does AdBlue in a diesel motor need its own filler? Many newer diesels on the roads around Steynton and Milford Haven carry two liquids, not one. Diesel goes to the motor. AdBlue goes to your exhaust, where it is sprayed into the gas to fresh it, and it lives in a tank of its own. Different tanks, different fillers. Many of cars share a single flap for both, whereas others put the AdBlue filler to the boot or under the bonnet. At the pump, your diesel side gets filled constantly. A driver who has to stop and work out where it goes usually fills the AdBlue side, from a bottle, and far less frequently. The mistake grows in that gap between the two. ## Steynton: how AdBlue in the diesel tank takes place Three things tend to come together, 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 car drops into limp mode. So the top-up is done in a hurry: on a drive off Jordan's Close before work, or in the car park at Horse and Jockey on the way home. The old car's cap is where your hand goes — but a hire car, a new car or a company car puts the fillers somewhere else. That is a second factor: an unfamiliar motor. Lastly, the bottle fits: diesel filler or AdBlue filler, it goes in just as easily, and once the tip starts, nothing stops it. Whether it happens in Thornton or the middle of Steynton, it is the same few seconds. ## How to tell the AdBlue filler from the diesel one Before you pour anything, whether on a driveway in Liddeston or a forecourt around Steynton, check these. They take a few seconds. - Check the cap rather than going by position: AdBlue ones are frequently blue or marked "AdBlue", and diesel caps usually aren't. - On many cars, size tells: AdBlue has the smaller filler neck. - The flap. Look inside the fuel flap for a label. Many motors say there which fuel goes where. - Can't find it beside the diesel filler? In that case check below the bonnet or inside the boot — the owner's manual says which. - The previous driver will know. Ask when you collect a rental or company car — from Milford Haven's car park, say — not when the warning appears. ## How to top up without AdBlue in your diesel tank For the day the warning appears — anywhere it is across Pembrokeshire — a routine to use. - Switch off after you park — level ground, motor stopped, and never rushed beside Steynton Road on the verge. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds daft and it does the trick. - Leave the diesel cap on. If both sit under one flap, check your diesel cap is still closed before you lift the bottle. - Using the bottle's own spout, tip slowly — and stop when it is full or the bottle is empty. - Only then, start the car: close the cap, check again, and make sure your diesel cap was never opened. Find at the second or third stage that AdBlue went in the wrong filler? That's where you stop. Do not go on to step five. ## AdBlue in your diesel tank already, around Steynton? The short order of things, beginning with no starting your engine. On plenty of diesels the ignition alone runs the fuel pump, and so don't switch the car on. Do not top up with diesel to thin it: AdBlue doesn't mix with diesel, it sinks to the bottom of that tank, where your fuel is pulled from. The attendants at the nearest petrol station, Tesco or another forecourt will usually lend a hand to push the car clear if you ask. At home around Steynton? Then the car remains put. Stop as soon as it is safe then switch off, if the motor has already run. The next junction means where to come off if you are on the M4, under 50 miles from Steynton. A short hop across Steynton is a smaller job than a run towards St Davids, under 15 miles away, so tell us about how far it went. ## Our arrival around Steynton, and what happens next Outside the local primary school, near St. Peter & St. Cewydd or on your own drive: wherever your car has stopped, we come to it. The answers decide this work and our price, and so our engineers ask what was put in, roughly how much, and whether it has run. That quote comes over the phone, before any van leaves. After that: a drain, then a thorough flush of the entire system. Much more than with petrol, it matters with AdBlue: the crystals form, some metals are attacked, and none of that washes out on its own, no matter how long it is left. After the filter has been cleaned — or renewed, if needed — clean diesel goes in, and then your car gets tested. Before we leave, our engineers fire it up and check that it's running properly. Unrun vehicles mostly need a half-hour job from the moment we arrive. The equipment is fine on a live filling station, and quiet enough for a driveway late at night. Nothing in advance; you settle up that day. Afterwards, a VAT invoice and a report from the engineer are handed to you for the insurer. While we travel, take a look at your insurance documents; plenty include cover for misfuelling. ## About Steynton Steynton is a small suburban area in Pembrokeshire, situated near the coast at an elevation of around 67 metres. Steynton lies close to several nearby places, including Thornton, Priory, and Pill, and is approximately 14.9 miles from St Davids. Steynton has a population of around 951 people and is characterised by predominantly detached housing. Steynton is located in a scenic part of Wales, with the city of London around 210 miles to the east. ## AdBlue drains across Pembrokeshire, Steynton included Throughout SA postcodes, our vans that cover Steynton — a residential suburb — work the surrounding locations too, Pill and Priory among them. A postcode starting SA73 1 gets the van to you fastest. There's no need to move the car. Anywhere it stands — near Thornton Hall, in a lay-by heading to Milford United Football Club, at home — that's where it is emptied. Guessing doesn't help at the back of Milford Haven Leisure Centre, on a border, or somewhere hard to pin down; phone and ask. ## The short version for Steynton drivers Read the cap before you pour. Petrol in Diesel drains it on the spot, anywhere across Pembrokeshire, if AdBlue has gone in your diesel tank regardless — so leave the vehicle off and phone 0333 366 0103.