--- title: Dereham: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/dereham-norfolk/ location: Dereham county: Norfolk latitude: 52.681980 longitude: 0.940460 service: AdBlue in a Diesel Tank updated: 2026-10-27 --- # AdBlue in a Diesel Tank in Dereham: Why It Happens and How to Avoid It If AdBlue is already in your diesel tank, stop reading for a moment: leave your motor and the ignition off and ring 0333 366 0103. Normally, if your motor hasn't run, it is drained and thoroughly rinsed where the car is in Dereham. Not happened yet? Below, the rest of the page covers the why it happens and the ways to prevent it altogether. ## Two fillers, two tanks: AdBlue in a diesel car Many newer diesels around Northall Green, as well as Dereham, run on two fluids; your engine gets only the diesel. Its own tank keeps it, and from there it goes to your exhaust, where a spray cleans the fumes. Different tanks, different fillers. Other vehicles put the AdBlue filler in the boot or under the bonnet; a lot more have the two together behind one flap. Filling your diesel side at the petrol pump happens all the time. Seldom filled, AdBlue normally goes in from a bottle, poured by someone who must stop and think which cap it needs. The mistake grows in that gap between the two. ## How does AdBlue in the diesel tank occur in Dereham? Carelessness seldom explains it. What does is three things lining up at once. Haste follows from the warning. Your car warns you as AdBlue runs low, and an empty tank puts it into limp mode — so the top-up gets done in a rush, before work on a drive off Market Place, or heading home in the car park at Red Lion. Then your car is unfamiliar. A hire car, a new vehicle or a company car puts the fillers where your last one did not, and the hand reaches for the cap it would have 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. Whether it occurs in Moorgate or the middle of Dereham, it's the same few seconds. ## How to tell the AdBlue filler from the diesel one Check these first, at a forecourt in Dereham or a driveway out in Toftwood. A few seconds, that's all. - The cap. The AdBlue cap is regularly blue, or marked "AdBlue". Your diesel cap normally isn't. Read it instead of going by where it sits. - Check the size: the smaller neck is, on many motors, the AdBlue one. - Look inside the fuel flap: many motors have a label there showing which fuel goes where. - The handbook. If your filler is not 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 — when you collect a hire or company car from somewhere like the car park at Wymondham. ## AdBlue top-ups that never reach the diesel tank Wherever across Norfolk the light comes on, here is a routine for the day. - Switch off after you park — flat ground, engine stopped, and never in a rush beside Quebec Street on the verge. - Locate the AdBlue filler, check the cap, and say the name "AdBlue" aloud as you unscrew it. It sounds silly. It does the trick. - The diesel cap stays on. When the two share a flap, confirm it is shut before lifting the bottle. - Finish once the tank fills or the bottle runs dry; before that, tip slowly through its built-in spout. - Shut the cap, and check again — making sure the diesel filler remained shut throughout. Only then, start your car. Find at step two or three that it's already gone into your diesel side? Then stop right there. Do not go on to step five. ## Dereham: already put AdBlue in your diesel tank? Then the order of things is short. Don't start the motor. On many diesels your ignition alone runs the fuel pump, and so don't switch it on. Don't top up with diesel to dilute it: AdBlue doesn't mix with diesel, it sinks to the bottom of the tank, where the fuel is drawn from. Ask the staff to help roll your car clear of the petrol pump if you're on a forecourt — the Morrisons, the BP or somewhere else. If you're on your own drive in Dereham, leave the car where it is. When the engine has run by now, pull over somewhere safe then switch the vehicle off. The next junction is where to leave when you are on the M11, under 50 miles from Dereham. Mileage matters — a short hop across Dereham makes a smaller job than driving under 25 miles to Norwich — so say about how far it went. ## What takes place when our engineers arrive in Dereham Our engineers come to your car wherever it has stopped, whether that is outside Dereham Church of England Infant and Nursery Academy, close to The Assembly Rooms or on your own drive. Which liquid was put in, the quantity, and if it ran: our engineers ask because the answers set the work and quote. On the phone call itself, you are told our quote — before anything else. The system is then cleaned thoroughly, once that tank is emptied. With AdBlue that counts more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, and so it doesn't wash out on its own. The filter is flushed, or replaced where it needs to be; fresh diesel goes in; and the car is tested. After that we start it and make sure it runs smoothly before we go. Using pumps safe on a working forecourt and quiet enough for use outside a house at night, most jobs where your engine hasn't run take about half an hour once we arrive. No money upfront; you settle up on the day. At the end, a VAT invoice and the report from the engineer go to you for the insurer. Wrong-fuel cover is part of plenty of insurance policies — so make use of the wait to check yours. ## About Dereham Dereham is a town in the heart of Norfolk, situated approximately 15 miles west of Norwich and 93 miles north-east of London. Dereham sits in a relatively low-lying area, with an average elevation of around 56 metres, and is surrounded by smaller settlements such as Moorgate and South Green. Dereham has a population of around 14,000 people, predominantly living in semi-detached housing. Dereham is a typical example of a small English town, with a mix of residential and commercial areas. ## AdBlue drains across Norfolk, Dereham included South Green and Dumpling Green are among the towns near Dereham, a town, that the same teams cover, throughout NR postcodes. The van reaches you fastest with a postcode starting NR19 2. Moving your car isn't necessary. The drain happens on the spot, whether a drive, a road near Dereham Town Monument, or a layby on the way to Queen Mothers Garden. Guessing won't help behind Cowper Congregational Church, on a border, or anywhere awkward to describe; ring and check. ## The short version for Dereham people Pour nothing until you've read the cap. Still AdBlue in the diesel tank? Petrol in Diesel can drain it wherever it stands, anywhere across Norfolk: keep it off then phone 0333 366 0103.