--- title: Explained: AdBlue in a Diesel Tank Gunnersbury canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/gunnersbury-greater-london/ location: Gunnersbury county: Greater London latitude: 51.487720 longitude: -0.267120 service: AdBlue in a Diesel Tank updated: 2026-10-17 --- # AdBlue in a Diesel Tank in Gunnersbury: Why It Happens and How to Stop It Leave the motor and ignition off and ring 0333 366 0103 first — reading can wait if AdBlue is already in the diesel tank. A drain plus a full flush, carried out right where your vehicle sits in Gunnersbury, is normally all it needs if caught before the engine runs. Not happened yet? Further down, the rest of the page explains the why it occurs and the how to prevent it for good. ## AdBlue in a diesel car, and its separate tank Diesel feeds your motor — but many modern diesels driven round Gunnersbury and Strand on the Green hold another fluid as well. Kept in a tank of its own, AdBlue is fed into the exhaust gas and cleans it. There is a filler for each tank. Some motors put the AdBlue filler in the boot or under the bonnet; a lot more place the two side by side under one flap. At the pump, the diesel side is topped up constantly. The AdBlue side is fuelled far less commonly, normally from a bottle, and usually by somebody who has to stop and think where it goes. Mistakes happen in the gap between them. ## Gunnersbury: how AdBlue in the diesel tank occurs Carelessness seldom explains it. Instead is three things lining up at once. Hurry follows 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 quickly, before work on a drive off Sutton Court Road, or on the way home in the car park outside Smokehouse. Then the vehicle is new. 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. 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 tip once it has started. The same few seconds settle it, in the middle of Gunnersbury or out in Chiswick. ## The AdBlue filler and the diesel filler: telling them apart A couple of seconds is all these take — so check them before you tip anything, on a drive in Bedford Park or a forecourt around Gunnersbury. - Check the cap rather than going by position: AdBlue ones are frequently blue or marked "AdBlue", and diesel ones normally are not. - The size. On many vehicles the AdBlue filler neck is the smaller of the two. - Look inside the fuel flap: many cars carry a label there saying which fuel goes where. - In your boot or under the bonnet: that is where your filler sits if it is not by your diesel cap, and the handbook tells you which. - Ask the person who drove it last — before you leave, not when the light comes on — when you pick up a hire or company car from somewhere like the car park outside the nearest station. ## How to top up without AdBlue in the diesel tank Anywhere around Greater London the light comes on, this is a routine for the day. - Switch off after you park — level ground, engine off, and not in a rush beside Cedars Road at the roadside. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds silly and it works. - Both under one flap? Then confirm the lid on your diesel filler stays closed before lifting the bottle. - Using the bottle's own spout, tip slowly — and stop when it is full or the bottle is empty. - Before you start the car, shut the cap and look a second time that your diesel cap never opened off. Stop there if you find, at step two or three, that you have already poured into your diesel side. Leave out stage five altogether. ## AdBlue in the diesel tank already, in Gunnersbury? What follows is a short order of things, starting with not starting your engine. On many diesels your ignition alone runs the fuel pump, so don't switch it on. AdBlue does not mix with diesel — it sinks to the bottom of that tank, where the fuel is pulled from — so don't top up with diesel to dilute it. The staff at BP, Esso or any forecourt will usually help to push your car away when asked. If you're on your own driveway in Gunnersbury, leave it where it is. Already started? Pull over once it's sensible, then switch off. Gunnersbury sits under a mile from the M4; on it, take the next exit. A short hop across Gunnersbury is a smaller job than a run towards Westminster, under 10 miles away, so tell us about how far it went. ## Gunnersbury: what happens when our technicians get there Our van reaches your car anywhere it has come to rest — your own drive, near Tommy Cooper, or by Grove Park Primary School. Our engineers ask what was put in, roughly how much, and if it's run, since those answers decide this work and the price. Nobody heads out until you've had the quote by phone. Then your tank is cleared and the fuel system purged thoroughly. More than with petrol, it counts here: crystals form, some metals are attacked, and none of it washes out unaided, however long it is left. Once the fuel filter has been cleaned — or replaced, if required — fresh diesel goes in, and then your vehicle is tested. Next our technicians fire it up and check it runs correctly before we leave. If your engine hasn't run, the majority of jobs take about half an hour once we're there, using pumps that are fine on a busy forecourt and quiet enough to use outside a house after dark. Paying is on the day, not upfront, and you receive the paperwork your insurer asks for: an engineer report and a VAT invoice. While we travel, have a look at your insurance documents; plenty carry cover for misfuelling. ## About Gunnersbury, for a moment Gunnersbury is a suburban area in west London, situated approximately 6.1 miles from Westminster and close to the River Thames. Gunnersbury sits near the borders of Chiswick, Grove Park, and Acton Green, with a population of around 11902 people. Gunnersbury is characterized by its predominantly flat housing stock, which reflects the area's urban development. Gunnersbury remains a residential community within the wider London urban area. ## AdBlue drains around Gunnersbury and across Greater London Being a residential suburb, Gunnersbury has the same vans as surrounding areas — Grove Park, Acton Green — right through W postcodes and the wider area around them. Fastest of all: quote a W4 4 postcode for the van. Shifting your car isn't needed. Wherever it stands — beside Patrick Hamilton, on a lay-by en route to Will To Win, on a drive — that is where it gets emptied. Guessing won't help behind St Michael, close to a boundary, or somewhere awkward to pin down; ring and check. ## In short, for Gunnersbury motorists Before you pour, read the cap. AdBlue in the diesel tank after all? Leave the vehicle off then call 0333 366 0103; Petrol in Diesel drains it on the spot, throughout Greater London.