--- title: Explained: AdBlue in a Diesel Tank Mountnessing canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/mountnessing-essex/ location: Mountnessing county: Essex latitude: 51.653490 longitude: 0.353100 service: AdBlue in a Diesel Tank updated: 2026-10-03 --- # Why It Occurs and How to Avoid It: AdBlue in a Diesel Tank in Mountnessing AdBlue already in your diesel tank? Then set this page aside for now, leave your ignition and motor off, and call 0333 366 0103. In Mountnessing, catching it before your motor runs usually leaves draining and a thorough flush on the spot. The remainder of this page explains why it takes place and how to ensure it does not — useful if you're reading ahead of time. ## AdBlue in a diesel motor: two tanks, two fillers Diesel goes to the engine — yet plenty of newer diesels driven around Mountnessing and Green Street carry a second fluid too. The exhaust, not your engine, is where AdBlue goes: dosed into the gas to clean them, from a separate tank. There is a filler for every tank. Many of motors have a single flap for both, while some put the AdBlue filler to your boot or under the bonnet. Diesel gets filled at every filling station call-out, week in, week out. The AdBlue side is topped up far less commonly, normally from a bottle, and normally by somebody who has to stop and think where it goes. The mistake lives in that gap. ## AdBlue in your diesel tank in Mountnessing: how it takes place Three things tend to come together, and carelessness is seldom one of them. Haste comes from the warning. The car warns you as AdBlue runs low, and a dry tank sends the vehicle into limp mode — so the top-up happens in a rush, before work on a drive off Roman Road, or heading home in the car park at The George and Dragon. Next, your hand reaches for the cap it would have used on the old car — because a rental car, a new vehicle or a company car puts the fillers where your last one did not. 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 once it has started. Whether it happens in Padhams Green or the middle of Mountnessing, it's the same few seconds. ## Which filler is for AdBlue, and which for diesel? Before you pour anything, whether on a driveway in Hutton or a forecourt in Mountnessing, check these. They take a couple of seconds. - Blue and lettering: an AdBlue cap is frequently blue, or says "AdBlue", where a diesel cap normally doesn't. Trust the cap, not where it sits. - Many cars fit AdBlue the smaller neck of the two. - Look inside your fuel flap: plenty of vehicles carry a label there saying which fuel goes where. - Cannot see it next to the diesel filler? In that case look beneath the bonnet or in your boot — the handbook will say where. - Picking up a hire or company car, perhaps at the car park outside Ingatestone? Ask whoever drove the vehicle last before leaving, not once the light goes on. ## Topping up AdBlue without it reaching the diesel tank Anywhere across Essex the light comes on, here is a routine for that day. - Pull in somewhere level, engine off, with time in hand — never hurried on the side of Crossby Close. - Silly as it sounds, speaking "AdBlue" aloud as you unscrew the cap does the trick — after you have located your filler and read it. - If both sit under one flap, check your diesel cap is still closed before you lift the bottle — and leave the car on. - Using the bottle's own spout, tip slowly — and stop when it is full or the bottle is empty. - Close the cap and check again. Make sure the diesel cap was never opened. Only then start the vehicle. Find during the second or third stage that the bottle went in the wrong filler? That's where you stop. Don't go on to step five. ## AdBlue in the diesel tank already, in Mountnessing? Brief list, then. First: the motor stays off. Leave your ignition off as well, since on many diesels it alone starts the fuel pump. Topping up with diesel will not dilute it: rather than mixing, AdBlue drops to the base of the tank, just where fuel is drawn from. Ask the staff to help roll the car away from the petrol pump if you are at a forecourt — the BP, the Esso or anywhere else. On your own drive around Mountnessing? Then the vehicle stays where it is. Stop as soon as it is safe and switch off, if your engine has already run. The next exit is the place to leave if you're on the M25, under 5 miles from Mountnessing. Mileage counts — a short hop across Mountnessing is a smaller job than driving under 10 miles to Chelmsford — so say roughly how far it went. ## When we turn up in Mountnessing, what happens? Outside Mountnessing Church of England Primary School, near St John's Church or on your own driveway: wherever the car has stopped, our technicians come to it. Those answers determine this work and our quote, so our engineers ask what went in, about how much, and whether it has run. That quote comes over the phone, before any van leaves. Your system is then flushed thoroughly, after your tank is drained. Much more than with petrol, it counts here: the crystals build up, some metals corrode, and none of it washes away on its own, however long it is left. After your filter is cleaned — or replaced, if required — clean diesel goes in, and then your car gets tested. Your engine is started next and tested to confirm it runs correctly, all before our technicians leave. Unstarted cars mostly mean a half-hour job after arrival. The kit is safe on a live filling station, and hushed enough for a residential street late at night. You pay on the day, with nothing upfront, and get a VAT invoice and an engineer report for your insurer. Wrong-fuel cover is included in plenty of insurance policies — and so use the wait to look at yours. ## About Mountnessing itself Mountnessing is a village in Essex, situated near the River Crouch and close to the nearby settlements of Padhams Green and Heybridge. Mountnessing sits at an elevation of around 70 metres, with semi-detached housing being the predominant type of accommodation. Mountnessing is located approximately 23 miles from London and 7.7 miles from Chelmsford, making it a commuter-friendly location. Mountnessing has a population of around 801 residents, who enjoy the village's riverside setting. ## Mountnessing and Essex: AdBlue drains across the area Mountnessing is a village, and our teams that cover it also work the places around it, Heybridge and Swallows Cross among them, across the CM postcode area. Give a postcode that starts CM15 0, and the van gets there quickest. Shifting the vehicle is not needed. The drain takes place on the spot, be it a driveway, a street near Mountnessing Village Hall, or a layby towards Icehouse Wood. If you are near a boundary, or somewhere hard to describe like the back of Ingatestone Village Sign, ring and ask instead of assuming. ## Mountnessing drivers: the short version Pour no AdBlue till you have read the cap. Petrol in Diesel empties it on the spot, anywhere across Essex, if AdBlue has gone in your diesel tank anyway — so leave the vehicle off then ring 0333 366 0103.