--- title: AdBlue in a Diesel Tank Sully? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/sully-the-vale-of-glamorgan/ location: Sully county: The Vale of Glamorgan latitude: 51.406480 longitude: -3.216780 service: AdBlue in a Diesel Tank updated: 2026-10-28 --- # Avoiding AdBlue in a Diesel Tank in Sully: Why It Happens Keep your motor and ignition off and call 0333 366 0103 first — the rest can wait if AdBlue is already in the diesel tank. Normally, when the motor hasn't turned, it's drained and thoroughly cleaned where the car is in Sully. Reading in advance? In that case the rest explains how it happens and how to prevent it ever happening. ## AdBlue in a diesel vehicle, and its separate tank Plenty of newer diesels in Cosmeston, as well as Sully, carry on two fluids; your engine takes only the diesel. Your exhaust, not your motor, is where AdBlue goes: dosed into the gas to fresh it, from a separate tank. Different tanks, different fillers. Other vehicles put the AdBlue filler in the boot or under the bonnet; plenty of others place both side by side under one flap. Filling your diesel side at the petrol pump happens all the time. The AdBlue side is fuelled far less often, usually from a bottle, and normally by a person who has to stop and think where it goes. It's in the gap that the error happens. ## Sully: how AdBlue in your diesel tank happens Three things tend to line up, and carelessness is rarely one of them. Haste follows from the warning. Your car tells you as AdBlue runs low, and an empty tank sends it into limp mode — so the top-up gets done quickly, before work on a drive off Minehead Avenue, or heading home in the car park outside Sully Inn. New-to-you cars come second, as well. Rentals, new vehicles and company vehicles put their fillers differently, and the hand goes for the cap it 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, so nothing stops the pour after it has started. It's seconds, whether in Swanbridge or bang in the heart of Sully. ## The AdBlue filler and the diesel filler: telling them apart A couple of seconds is all these take — so run through them before you tip anything, on a drive in Cadoxton or a forecourt in Sully. - Position misleads; the cap doesn't. AdBlue caps tend to be blue or carry the word "AdBlue" — diesel caps normally do not. - Plenty of vehicles fit AdBlue the smaller neck of the two. - Lift the flap and look for a label — plenty of motors mark what belongs in which filler just there. - The handbook. If your filler isn't by your diesel cap, it is in your boot or under the bonnet, and the handbook says which. - Ask the person who drove it last — before you leave, not when the light comes on — if you pick up a hire or company car from somewhere like the car park outside Cadoxton. ## Keeping AdBlue out of your diesel tank when you top up 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 South Road. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds daft and it works. - The diesel cap stays on. When the two share a flap, make sure it is shut before the bottle comes up. - Pour slowly, using the bottle's own spout. Stop when it's full or when the bottle is empty. - Shut the cap, and look once more — confirm your diesel cap stayed shut throughout. Only then, start the vehicle. If at step two or three you find you have already poured into your diesel side, stop there. Stage five is out. ## Sully: already put AdBlue in your diesel tank? Don't start your engine: that's how the short order of things starts. Don't switch the ignition on; on plenty of diesels that alone runs the fuel 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 your fuel is sucked from. The attendants at Cardiff Gas - autogas, Texaco or another forecourt will usually lend a hand to push the car away when you ask. Your own drive around Sully is where it stays. When your motor has run by now, pull over somewhere safe and switch the car off. Leave the M4 — under 10 miles out of Sully — at the next exit. Tell us about how far it went: a run towards Cardiff, under 10 miles away, is a bigger job than a short hop across Sully. ## When our engineers turn up in Sully, what happens? We come to the car wherever it has stopped, whether that's outside the local primary school, close to The Old School or on your own driveway. Which liquid was put in, the quantity, and whether it ran: our engineers ask because those answers set the work and price. During the phone call itself, you are told our quote — before anything else. Next: a drain, then a full flush of the entire system. With AdBlue that counts more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, so it doesn't wash out on its own. A test comes at the end: before that, clean diesel is added, and the filter is flushed or changed as needed. We do not go until it has been fired up and is running smoothly. Most jobs are finished in roughly half an hour once our engineers get there, as long as the engine has not run — and the pumps our engineers use are fine on a live forecourt yet quiet at night outside a house. Payment is on the day, not upfront, and you receive the paperwork your insurer asks for: an engineer report and a VAT invoice. Before we get there, have a look at your policy; many carry cover for misfuelling. ## About Sully and where it is Sully is a coastal suburban area in The Vale of Glamorgan, situated near the mouth of the Bristol Channel, with Swanbridge and Cog to the west. Sully sits at an elevation of around 23 metres, looking out over the sea towards the English coast. Sully has a mix of housing types, but detached homes are particularly prevalent in the area. Sully is located close to Cardiff, the capital city of Wales, which is about 5 miles to the northeast. ## Sully and The Vale of Glamorgan: AdBlue drains across the area Sully is a residential suburb, and the vans that cover it also work the places around it, Cog and Palmerstown among them, across the CF postcode area. A postcode starting CF64 5 gets the van to you fastest. No need to move the vehicle. A drive, a lay-by on the way to Sully Centurions Cricket Club Ground, a side street near Church of St John the Baptist: we drain it where it stands. Guessing won't help behind Sully & Lavernock Community Library Trust, close to a border, or anywhere awkward to describe; ring and check. ## For Sully drivers, the short version Tip nothing until you've read the cap. Petrol in Diesel drains it on the spot, anywhere around The Vale of Glamorgan, if AdBlue has gone in the diesel tank all the same — so leave the car off and ring 0333 366 0103.