--- title: AdBlue in a Diesel Tank Carshalton on the Hill? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/carshalton-on-the-hill-greater-london/ location: Carshalton on the Hill county: Greater London latitude: 51.354520 longitude: -0.163510 service: AdBlue in a Diesel Tank updated: 2026-10-16 --- # Avoiding AdBlue in a Diesel Tank in Carshalton on the Hill: Why It Happens Pause here a minute if the diesel tank already holds AdBlue in it: ignition off, engine off, and call 0333 366 0103. In Carshalton on the Hill, catching it before your motor runs usually means draining and a thorough flush where it stands. Not happened yet? Further down, the rest of the page explains the reasons it happens and the how to avoid it altogether. ## AdBlue in a diesel car: two tanks, two fillers Diesel goes to your engine — but many current diesels driven around Carshalton on the Hill and Woodcote Green hold another fluid too. Stored in a tank of its own, AdBlue is fed into the exhaust gas and cleans it. Every tank comes with a filler of its own. On a lot of vehicles the two sit side by side under the same flap; on others the AdBlue filler is in your boot or under the bonnet. The diesel side is topped up at the pump all the time. Much less frequently, the AdBlue side gets filled — normally from a bottle, by a person working out where it goes. The error lives in that gap. ## How AdBlue in your diesel tank takes place around Carshalton on the Hill It is hardly ever carelessness. Three things tend to line up. To start with, the warning. Low AdBlue brings a message from the vehicle, and running out leads to limp mode — hence a hurried top-up, perhaps before work off Fir Tree Grove, perhaps at The Windsor Castle on the way home that evening. Then the vehicle is unfamiliar. A hire car, a new car or a company car puts the fillers where your last one didn't, and your hand reaches for the cap it would have used on the old one. Lastly, the bottle goes in: diesel filler or AdBlue one, it goes in just as readily, and after the pour begins, no part halts it. Wallington or the middle of Carshalton on the Hill: it takes the same few seconds in both. ## How to tell the AdBlue filler from the diesel one Before you pour anything, whether on a drive in South Beddington or a forecourt around Carshalton on the Hill, check these. They take a couple of seconds. - The cap. The AdBlue cap is regularly blue, or marked "AdBlue". The diesel cap usually isn't. Read it rather than going by where it sits. - The size. On plenty of motors the AdBlue filler neck is the smaller of the two. - Open the flap and look for a label — plenty of cars show what goes in which filler just there. - The handbook. If your filler isn't by your diesel cap, it's in the boot or under the bonnet, and the handbook says which. - Collecting a hire or company car, perhaps at the car park outside Carshalton Beeches? Ask whoever drove it last before leaving, rather than once the light goes on. ## Keeping AdBlue out of the diesel tank when you top up Wherever around Greater London the light comes on, this is a routine for that day. - Turn off after you park — level ground, engine stopped, and never in a rush by North Avenue on the verge. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds silly and it works. - If both sit under one flap, check your diesel cap is still closed before you lift the bottle — then leave the vehicle on. - Finish when the tank is topped up or the bottle is empty; until then, pour slowly through the built-in spout. - Close the cap, and look again — confirm the diesel cap stayed closed the whole time. Only then, start your car. If at stage two or three you find you have already poured into the diesel side, stop there. Leave out step five altogether. ## Put AdBlue in the diesel tank in Carshalton on the Hill already? What follows is a short order of things, beginning with not starting the motor. Leave your ignition off as well, because on plenty of diesels switching it on by itself runs your pump. AdBlue does not mix with diesel — it sinks to the bottom of that tank, where the fuel is drawn from — so don't top up with diesel to thin it. If you are at a forecourt, whether it is the BP or the Shell, ask the attendants to help roll the car away from the petrol pump. Your own drive around Carshalton on the Hill is where it stays. Already run? Stop when it is sensible, then turn off. Leave the M23 — under 5 miles out of Carshalton on the Hill — at the next exit. About how far did it go? Crossing Carshalton on the Hill is smaller a job than a run of under 15 miles towards Westminster, and so say. ## Carshalton on the Hill: what occurs when our engineers turn up Outside Stanley Park Infants School, near Del Toro Dance School or on your own drive: wherever the car has stopped, we come to it. Those answers decide this work and the quote, and so we ask what got in, roughly how much, and whether it has run. On the call itself, you hear the quote — before dispatch. After that: draining, then a thorough flush of the entire system. Not like petrol, AdBlue forms crystals and eats at certain fuel-system metals, and neither washes away unaided. Hence it matters more. The filter is cleaned, or replaced where it needs to be; fresh diesel goes in; and the car is tested. Then we start the engine and check it runs smoothly before we go. Unstarted cars usually need a half-hour visit from arrival. The kit is safe on a live forecourt, and quiet enough for a driveway late at night. No money in advance; you settle up on the day. Afterwards, the VAT invoice and a report from the engineer go to you for your insurer. Wrong-fuel cover is part of many insurance policies — so make use of the wait to look at yours. ## About Carshalton on the Hill, for a moment Carshalton on the Hill is a suburban area in south London, situated approximately 10.7 miles from central London and 10.2 miles from Westminster. Carshalton on the Hill has a population of around 7783 people and is characterised by semi-detached housing. Carshalton on the Hill sits at an elevation of 79 metres, inland from the Thames River, and is near neighbouring areas such as Wallington and Carshalton Beeches. ## AdBlue drains across Greater London, Carshalton on the Hill included Carshalton Beeches and Carshalton are among the places near Carshalton on the Hill, a residential suburb, that the same vans cover, over SM postcodes. Quickest of all: quote a SM5 3 postcode to our van. The vehicle remains where it is. Wherever it stands — near Church of the Good Shepherd, in a layby heading to Stanley Park, at home — that's where it gets drained. Guessing won't help at the back of Carshalton Tennis Club, close to a border, or anywhere awkward to pin down; ring and check. ## For Carshalton on the Hill people, the short version Read the cap before you tip. Petrol in Diesel drains it on the spot, anywhere across Greater London, if AdBlue has gone in the diesel tank anyway — and so leave the vehicle off then call 0333 366 0103.