--- title: AdBlue in a Diesel Tank Blackfriars? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/blackfriars-greater-london/ location: Blackfriars county: Greater London latitude: 51.512000 longitude: -0.104000 service: AdBlue in a Diesel Tank updated: 2026-10-10 --- # Why It Occurs and How to Avoid It: AdBlue in a Diesel Tank in Blackfriars If AdBlue is already in your diesel tank, stop reading for a moment: leave the engine and the ignition off then call 0333 366 0103. Usually, if the motor has not run, it's drained and fully purged where the vehicle sits around Blackfriars. 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 vehicle: two tanks, two fillers Diesel feeds the engine — yet plenty of current diesels seen round Blackfriars and London carry another liquid as well. Its own tank holds it, and from there it is sent to your exhaust, and there spraying treats the fumes. Each tank has one filler of its own. Many of cars share a single flap for both, whereas some put the AdBlue filler to the boot or under the bonnet. The diesel side is filled at the pump all the time. Rarely topped up, AdBlue usually goes in out of a bottle, poured by someone who has to stop and think what filler to use. That gap is where the error lives. ## How AdBlue in the diesel tank happens around Blackfriars Carelessness rarely explains it. Instead is three things lining up at once. The warning comes first. As AdBlue runs low your car tells you, and if it runs out completely, the vehicle drops into limp mode. So the top-up is done in a hurry: on a driveway off New Bridge Street before work, or in the car park at The Blackfriar on the way home. Then the vehicle is unfamiliar. A hire car, a new motor or a company car puts the fillers where your last one didn't, and your hand hits for the cap it would have used on the old one. No part halts the tip once it has started, because a bottle with a spout goes into a diesel filler as readily as an AdBlue one. The bottle fits. It's a few seconds, whether in Temple or bang in the heart of Blackfriars. ## Which filler is for AdBlue, and which for diesel? Look at these before pouring, on a forecourt in Blackfriars or a drive out in Aldwych. Seconds, no more. - Colour and lettering: an AdBlue cap is frequently blue, or says "AdBlue", where a diesel cap usually does not. Go by the cap, not where it sits. - On many motors, size tells: AdBlue gets the smaller filler neck. - A label inside your fuel flap often says which fuel goes where, on many motors. Check for it. - The handbook says which it lives when your filler is not next to the diesel cap: the boot, or under the bonnet. - Collecting a hire or company car, perhaps at the car park outside London Blackfriars? Check with whoever drove the vehicle last before you set off, not when the light comes on. ## How to top up without AdBlue in the diesel tank When the light comes on, wherever around Greater London, follow this routine. - Park and switch off. Not on a slope, not with the motor running, and not in a rush on the side of Watergate. - Say "AdBlue" out loud as you unscrew the cap, once finding the AdBlue filler and read it. Daft, perhaps, but it works. - If both sit under one flap, check your diesel cap is still closed before you lift the bottle — then leave the vehicle on. - Stop when that tank is topped up or the bottle runs dry; until then, pour slowly using the built-in spout. - Before you start your car, close the cap and look a second time that your diesel cap was never came off. Find at the second or third step that AdBlue went in the diesel filler? That's where you stop. Do not go on to step five. ## Blackfriars: already put AdBlue in your diesel tank? What follows is a short order of things, beginning with no starting the engine. The fuel pump starts on many diesels the moment your ignition goes on — so keep it off. Do not top up with diesel to thin it: AdBlue doesn't mix with diesel, it sinks to the bottom of your tank, where your fuel is drawn from. The attendants at Texaco, Shell or any forecourt will normally lend a hand to push the car clear if asked. If you are on your own driveway in Blackfriars, leave the car where it stands. Where the motor has been run already, pull over somewhere safe and switch the car off. On the M1, under 10 miles from Blackfriars, that means the next junction. Mileage matters — a quick hop across Blackfriars makes a smaller job than driving under a mile to London — so tell us roughly how far it went. ## Blackfriars: what occurs when our engineers turn up By St Alban's Church of England Primary School, near Queen Victoria or on your own drive: wherever the car has stopped, our technicians come to it. What liquid was put in, the quantity, and whether it ran: our technicians ask since those answers set the work and price. Nobody heads out before you've heard the quote over the phone. After that: a drain, then a thorough flush of the entire system. Not like petrol, AdBlue leaves crystals and attacks certain fuel-system metals, and neither washes away by itself. That is why it matters more. The fuel filter is cleaned, or replaced where it needs to be; clean diesel goes in; and your car is tested. After that our engineers fire it up and check it runs correctly before we go. Unstarted vehicles usually mean a half-hour job from the moment we arrive. The kit is safe on a busy forecourt, and hushed enough for a residential street late at night. Your insurer usually wants the engineer's report and your VAT invoice, and both are yours at the end. Payment comes on the day, with no deposit. It is worth looking at your policy while we travel to you: misfuelling cover is included with many policies. ## About Blackfriars itself Blackfriars is a suburban area in central London, situated on the north bank of the River Thames. Blackfriars sits at a low elevation of around 15 metres, close to the city's financial and commercial hubs. Blackfriars is characterized by its predominantly flat-type housing and its proximity to nearby areas such as Temple, Bankside, and Holborn. ## AdBlue drains about Blackfriars, and Greater London beyond Being a residential suburb, Blackfriars shares its vans surrounding places — Bankside, Holborn — right through EC4V postcodes and the wider area around them. Quickest of all: quote a EC4V 4 postcode to the van. Shifting the car isn't needed. We drain it where it is — a side street near St George and the Dragon, a lay-by on the way to St Anne Blackfriars Ireland Yard, a driveway. If you're near a border, or somewhere hard to describe like the back of Bridewell Theatre, ring and ask instead of guessing. ## Blackfriars people: the short version First, the cap; after that, the tip. If AdBlue has gone in your diesel tank anyway, leave the vehicle off and phone 0333 366 0103. Petrol in Diesel empties it where it stands, anywhere across Greater London.