--- title: Explained: AdBlue in a Diesel Tank Highgate canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/highgate-greater-london/ location: Highgate county: Greater London latitude: 51.577790 longitude: -0.152870 service: AdBlue in a Diesel Tank updated: 2026-10-06 --- # Why It Occurs and How to Avoid It: AdBlue in a Diesel Tank in Highgate Stop reading a minute when your diesel tank already holds AdBlue in it: ignition off, engine off, then call 0333 366 0103. Normally, if the motor has not run, it is emptied and fully flushed where your vehicle is around Highgate. Not happened yet? Below, the page explains the reasons it happens and the how to avoid it altogether. ## Why does AdBlue in a diesel motor need its own filler? Many newer diesels around East Finchley, like those in Highgate, run on two fluids; your motor takes just your diesel. Kept in a tank of its own, AdBlue is sprayed into your exhaust stream to clean it. Each tank has its own filler. Many of vehicles have a single flap for both, whereas some put the AdBlue filler to the boot or under the bonnet. Filling the diesel side at the pump happens constantly. A driver who has to stop and work out where it goes normally fills the AdBlue side, from a bottle, and much less commonly. The mistake grows in the gap between them. ## How does AdBlue in the diesel tank take place around Highgate? It's rarely carelessness. Three things tend to line up. The warning comes first. As AdBlue runs low the car tells you, and if it runs out altogether, the vehicle goes into limp mode. So the top-up is done in a hurry: on a driveway off North Hill before work, or in the car park outside The Highgate Inn on the way home. New-to-you cars come next, too. Hire cars, new motors and company vehicles put their fillers in new places, and the hand reaches for the cap 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 tip after it has started. Fortis Green or the heart of Highgate: it takes the same few seconds either way. ## Telling the AdBlue filler from the diesel filler Before you tip anything, whether on a drive in Crouch End or a forecourt in Highgate, check these. They take a couple of seconds. - Check the cap instead of going by where it sits: AdBlue caps are commonly blue or marked "AdBlue", and diesel ones usually are not. - The size. On plenty of motors the AdBlue filler neck is the smaller of the two. - The flap. Look inside your fuel flap for a label. Plenty of cars say there which fuel goes where. - In the boot or under the bonnet: that is where your filler sits if it is not by the diesel cap, and the handbook tells you which. - The previous driver knows. Check when you collect a hire car or company car — at Upper Holloway's car park, perhaps — rather than once the light appears. ## How to top up without AdBlue in your diesel tank A routine for the day the light comes on, wherever in Greater London that is. - Switch off after you park — flat ground, engine off, and not rushed by View Road on the verge. - Silly as it sounds, speaking "AdBlue" out loud as you unscrew the cap does the trick — after you've found your filler and read the cap. - The diesel cap remains on. Where the two sit under a flap, make sure it is shut before the bottle comes up. - Stop when that tank fills or the bottle runs dry; before that, pour gently through its own spout. - Only after that, start the car: close the cap, check a second time, and make sure your diesel cap was never opened. Stop there if you find, at stage two or three, that you have already poured into the diesel side. Stage five stays off limits. ## Put AdBlue in the diesel tank in Highgate already? What follows is a short order of things, starting with no starting the engine. On many diesels your ignition alone runs the fuel pump, so don't switch the vehicle on. Diluting it with extra diesel won't work, since AdBlue sinks to the bottom instead of mixing — and that's where your fuel is sucked from. If you're at a forecourt, whether it's the Esso or the Gulf, ask the attendants to help roll the car clear of the pump. Your own driveway around Highgate is where it should stay. Where the motor has been run by now, stop safely and switch the car off. Come off the M1 — under 5 miles out of Highgate — at the next exit. Distance counts — a quick hop across Highgate is a smaller job than driving under 10 miles towards London — so tell us about how far it went. ## Our arrival in Highgate, and what occurs next Our technicians come to the vehicle wherever it has stopped, whether that is outside Highgate Primary School, close to All Saints or on your own driveway. Our engineers ask what was put in, roughly how much, and whether it has run, since those replies settle the work and our price. You get that price by phone, before anybody heads out. Next: a drain, then a thorough flush of the entire system. Unlike petrol, AdBlue leaves crystals and attacks certain fuel-system metals, and neither washes away unaided. Hence it counts more. Your filter is cleaned, or replaced where it needs to be; fresh diesel goes in; and the car is tested. The engine is fired up next and checked to confirm it runs correctly, all before our technicians head off. Using pumps fine on a busy forecourt and quiet enough for use outside a house at night, most jobs in which your engine has not run take about half an hour once our engineers are there. Paying happens on the day, not upfront, and you receive the paperwork an insurer wants: an engineer report and a VAT invoice. Plenty of insurance policies include misfuelling cover, and so it's worth checking yours whilst we are on the way. ## About Highgate itself Highgate is a suburban area in northern London, situated on a ridge at an elevation of around 90 metres, overlooking the surrounding landscape. Highgate is characterized by its predominantly flat-type housing and is located near the riverside, with nearby places including Fortis Green, Cranley Gardens, and Parliament Hill. Highgate has a population of approximately 5946 residents and is positioned about 5 miles from central London. ## AdBlue drains in Highgate and across Greater London Cranley Gardens and Parliament Hill are among the towns around Highgate, a residential suburb, that the same teams cover, throughout N postcodes. Quickest of all: quote a N6 4 postcode for the van. Moving your car is not needed. Our engineers drain it where it is — a side street near Mallinson Sports Centre, a lay-by on the way to Tatham's Field, a driveway. If you're close to a boundary, or somewhere hard to explain like the back of Highgate Synagogue, ring and ask instead of guessing. ## For Highgate people, the short version Pour nothing till you have read the cap. Still AdBlue in your diesel tank? Petrol in Diesel can drain it wherever it stands, wherever in Greater London: switch the vehicle off and ring 0333 366 0103.