--- title: Explained: AdBlue in a Diesel Tank Soho canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/soho-greater-london/ location: Soho county: Greater London latitude: 51.512980 longitude: -0.133710 service: AdBlue in a Diesel Tank updated: 2026-10-16 --- # AdBlue in a Diesel Tank in Soho: Why It Happens and How to Prevent It Stop reading for a moment if your diesel tank already has AdBlue in it: ignition off, engine off, then phone 0333 366 0103. A drain and a thorough flush, done right where the vehicle stands around Soho, is usually all it takes if found before the motor runs. Reading in advance? In that case what follows explains how it happens and what to prevent it happening at all. ## Two fillers, two tanks: AdBlue in a diesel motor Not one fluid but two: that is how plenty of newer diesels near Soho and St Jamess run, with diesel feeding your engine. Your exhaust, not your engine, is where AdBlue goes: dosed into the gas to fresh it, from a separate tank. Different tanks, separate fillers. Plenty of motors have a single flap for both, whereas some move the AdBlue filler to the boot or under the bonnet. Filling your diesel side at the pump goes on constantly. Far less regularly, the AdBlue side is filled — normally from a bottle, by someone thinking about where it goes. That gap is where the error lives. ## How AdBlue in the diesel tank takes place in Soho Carelessness rarely causes it. Instead is three things lining up together. Haste comes from the warning. The car warns you as AdBlue runs low, and an empty tank sends it into limp mode — so the top-up happens quickly, before work on a driveway off Peter Street, or heading home in the car park at Duke of Wellington. Next, the hand reaches for the cap it would have used on the old vehicle — since a rental car, a new car or a company car puts the fillers somewhere your last one did not. Third, the spout goes in: a diesel filler or AdBlue one, it goes in as readily, and after the tip starts, no part stops it. Whether it occurs in Chinatown or the middle of Soho, it's the same few seconds. ## How to tell the AdBlue filler from the diesel one Before you pour anything, whether on a driveway in Charing Cross or a forecourt around Soho, check these. They take a few seconds. - Check the cap instead of going by position: AdBlue caps are commonly blue or marked "AdBlue", and diesel ones usually aren't. - Plenty of motors give AdBlue the smaller filler of the two. - A label inside the fuel flap frequently says which fuel goes where, on plenty of vehicles. Check for it. - The handbook. If your filler isn't by your diesel cap, it's in the boot or under the bonnet, and the handbook says which. - Collecting a hire or company car, perhaps at the car park at Tottenham Court Road? Ask the person who drove the vehicle last before you set off, rather than when the light goes on. ## Keeping AdBlue out of the diesel tank when you top up For the day the light appears — wherever it is across Greater London — a simple routine to use. - Not in a rush on the side of Berwick Street, not on a slope, not with the motor running: park then switch off properly. - Say "AdBlue" out loud as you unscrew the cap, once you find the AdBlue filler and reading it. Silly, perhaps, yet it works. - The diesel cap stays on. Where the two sit under a flap, make sure it's closed before the bottle comes up. - Stop once the tank fills or the bottle runs dry; until then, pour slowly through the built-in spout. - Before you start the vehicle, close the cap and check a second time that your diesel cap was never came off. Stop there if you find, at stage two or three, that you've already poured into your diesel side. Skip step five entirely. ## Soho: already put AdBlue in the diesel tank? Brief list, then. Top of it: your motor stays unstarted. The fuel pump runs on plenty of diesels the moment your ignition is switched on — and so keep it off. Do not top up with diesel to dilute it: AdBlue doesn't mix with diesel, it sinks to the bottom of that tank, where your fuel is drawn from. If you're on a forecourt, whether it's the Esso or the BP, ask the staff to help push your car away from the pump. If you are on your own drive around Soho, leave the car where it is. Already run? Pull over when it's sensible, then turn off. The next junction is where to leave if you're on the M1, under 10 miles from Soho. Mileage matters — a short hop across Soho makes a smaller job than driving under a mile to Westminster — so say roughly how far it went. ## Our arrival in Soho, and what happens next We come to your car wherever it has stopped, whether that is outside Soho Parish CofE Primary School, close to underbelly or on your own driveway. Both the work and our quote depend on three answers — which fluid, which amount, and whether it's run — so we ask. During the phone call itself, you are told our quote — before dispatch. Then that tank is drained and your system purged thoroughly. 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 with AdBlue than with petrol. The filter is cleaned, or replaced where it needs to be; fresh diesel goes in; and the car is tested. Before leaving, our engineers fire it up and confirm that it's running smoothly. With pumps fine on a busy forecourt and quiet enough to use outside a house at night, most jobs in which the motor hasn't run need roughly half an hour after our technicians are there. Paying happens on the day, not upfront, and you receive the documents your insurer wants: an engineer report and a VAT invoice. While we travel, have a look at your insurance documents; many include cover for misfuelling. ## About Soho Soho is a densely populated suburban area in central London, situated near the River Thames and close to major landmarks like Chinatown and the Strand. Soho sits at a relatively low elevation of 34 metres, with its residential areas predominantly consisting of flats. Soho is surrounded by other notable areas, including St Giles and Westminster, which is approximately 0.9 miles away. ## Soho and Greater London: AdBlue drains across the area Over W1F postcodes, our vans covering Soho — a residential suburb — work the surrounding locations too, St Giles and Strand among them. Quote a postcode that starts W1F 0, and the van gets there quickest. No need to move your car. The drain takes place on the spot, be it a driveway, a street near Boulevard Theatre, or a layby towards St Anne's Churchyard. Awkward to explain, like the back of Plaque: Keith Moon? Close to a county line? Asking is better than guessing, and so phone. ## For Soho people, the short version Before you pour, read the cap. Petrol in Diesel empties it where it stands, anywhere around Greater London, if AdBlue has gone in your diesel tank regardless — so leave it off then ring 0333 366 0103.