--- title: Explained: AdBlue in a Diesel Tank Old Heath canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/old-heath-essex/ location: Old Heath county: Essex latitude: 51.872680 longitude: 0.924740 service: AdBlue in a Diesel Tank updated: 2026-10-24 --- # How It Occurs and How to Avoid It: AdBlue in a Diesel Tank in Old Heath AdBlue already in the diesel tank? In that case put this page aside a moment, keep the ignition and engine off, and phone 0333 366 0103. A drain and a full flush, done just where your car sits in Old Heath, is normally all it takes when found before the engine runs. Nothing happened yet? Further down, the rest of the page covers the reasons it takes place and the ways to avoid it altogether. ## Two fillers, two tanks: AdBlue in a diesel vehicle Plenty of newer diesels on the roads around Old Heath and Greenstead carry two liquids, not one. Diesel goes to your engine. AdBlue goes to your exhaust, where it is sprayed into the gas to fresh it, and it lives in a tank of its own. Different tanks, separate fillers. On a lot of motors the two sit side by side under the same flap; on others the AdBlue filler is in the boot or under the bonnet. At the pump, your diesel side is topped up all the time. The AdBlue side is topped up far less commonly, normally from a bottle, and normally by a person who has to stop and think where it goes. The mistake grows in the gap between them. ## How does AdBlue in the diesel tank take place around Old Heath? Three things tend to come together, and carelessness is seldom one of them. On a drive off D'arcy Road before work, or in the car park outside The Spinnaker heading home: that's where the hurried top-up takes place. Why the rush? As AdBlue gets low your car tells you, and if it is empty, limp mode kicks in. The old car's filler is where the hand reaches — but a hire car, a new car or a company car keeps the fillers elsewhere. That's the second factor: an unfamiliar vehicle. And the bottle fits. A bottle with a spout goes into a diesel filler as easily as an AdBlue one, and so nothing stops the pour once it has started. The same few seconds decide it, in the middle of Old Heath or out in The Hythe. ## The AdBlue filler and the diesel filler: telling them apart Look at these first, on a forecourt around Old Heath or a driveway out in Abbey Field. A few seconds, no more. - The cap. The AdBlue cap is regularly blue, or marked "AdBlue". The diesel cap normally is not. Read it instead of going by position. - Check the size: the smaller filler neck is, on plenty of vehicles, the AdBlue one. - Check inside the fuel flap: plenty of motors carry a label there saying which fuel goes where. - The handbook. If the filler is not by your diesel cap, it's in the boot or under the bonnet, and the handbook says which. - The previous driver will know. Check when you collect a rental or fleet car — at Hythe's car park, say — not when the light comes on. ## Topping up AdBlue without it reaching the diesel tank A routine for the day the light comes on, wherever in Essex that is. - Not in a rush on the side of Whitehall Road, not on a slope, not with your engine running: park then switch off first. - Say "AdBlue" out loud as you unscrew the cap, once you find the AdBlue filler and reading it. Silly, perhaps, but it works. - The diesel cap stays on. When both share a flap, make sure it is closed before lifting the bottle. - Pour slowly, using the bottle's own spout. Stop when it is full or when the bottle is empty. - Only then, start the vehicle: close the cap, check again, and make sure the diesel cap was never opened. Stop there if you find, at stage two or three, that you've already poured into your diesel side. Stage five is out. ## Already put AdBlue in your diesel tank around Old Heath? The short order of things, starting with no starting the engine. Don't switch your ignition on; on many diesels that alone runs the fuel pump. AdBlue doesn't mix with diesel — it sinks to the bottom of your tank, where the fuel is pulled from — so don't top up with diesel to dilute it. Ask the attendants to help roll the vehicle clear of the pump if you are on a forecourt — the Murco, the BP or somewhere else. Leave it where it is if you're on your own drive in Old Heath. When your engine has run already, stop safely and turn the vehicle off. The next junction is where to leave if you are on the M11, under 50 miles from Old Heath. A short hop across Old Heath is a smaller job than a run towards Colchester, under 3 miles away, and so tell us roughly how far it went. ## What happens when we arrive in Old Heath Outside Old Heath Community Primary School, close to Old Heath Community Centre or on your own driveway: wherever your car has stopped, our engineers come to it. What liquid went in, the quantity, and if it ran: our technicians ask because the answers set both work and quote. Nobody sets off until you have had our quote by phone. The fuel system is then rinsed thoroughly, after your tank is emptied. Much more than with petrol, it counts with AdBlue: the crystals form, some metals are attacked, and nothing clears away on its own, however long it is left. The filter is cleaned, or replaced where it needs to be; clean diesel goes in; and your car is tested. Your engine is fired up next and checked to make sure it runs correctly, all before our engineers go. If the engine hasn't run, the majority of jobs take about half an hour once we are there, using pumps that are fine on a busy forecourt and quiet enough to use outside a house after dark. Payment happens on the day, not upfront, and you receive the paperwork an insurer asks for: an engineer report and a VAT invoice. Many insurance policies include misfuelling cover, so it's worth checking yours whilst we are on the way. ## About Old Heath Old Heath is a suburban area located on the riverside in Essex, with a relatively low elevation of around 20 metres. Old Heath sits near the city of Colchester, approximately 1.6 miles away, and is close to other nearby places such as The Hythe and Berechurch. Old Heath is predominantly composed of flat housing, which is home to a population of around 3617 residents. Old Heath is also situated a considerable distance from London, at around 51.7 miles away. ## AdBlue drains in Old Heath and across Essex Being a residential suburb, Old Heath has the same vans as nearby areas — Berechurch, Blackheath — right through CO postcodes and the wider area around them. The van gets to you fastest with a postcode starting CO2 8. No need to move your car. A drive, a lay-by on the way to Scarletts Wood, a side street near St Barnabas, Old Heath: our engineers drain it where it sits. If you're close to a boundary, or somewhere hard to explain like the back of Colchester Christian Spiritualist Church, ring and ask instead of guessing. ## The short version for Old Heath people Before you tip, read the cap. If AdBlue has gone in your diesel tank anyway, leave the car off and ring 0333 366 0103. Petrol in Diesel empties it where it waits, anywhere around Essex.