--- title: Explained: AdBlue in a Diesel Tank Crawley Hill canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/crawley-hill-surrey/ location: Crawley Hill county: Surrey latitude: 51.336240 longitude: -0.731780 service: AdBlue in a Diesel Tank updated: 2026-10-02 --- # Crawley Hill: How Does AdBlue End Up in a Diesel Tank, and How Do You Prevent It? Keep your engine and ignition off and phone 0333 366 0103 now — the rest can wait when AdBlue is already in your diesel tank. Usually, when the engine hasn't run, it is drained and thoroughly rinsed where the car sits in Crawley Hill. The rest of this page covers why it happens and how to make sure it doesn't — handy if you're reading before it has happened. ## AdBlue in a diesel car: two tanks, two fillers Many current diesels on the roads round Crawley Hill and Frimley carry two liquids, not one. Diesel goes to your motor. AdBlue's own tank holds it, and from there it is sent to the exhaust, where spraying cleans the gas. Each tank has a filler of its own. Under one flap, side by side: that's the layout on many cars. On others, AdBlue's filler sits under the bonnet or in your boot instead. Filling your diesel side at the petrol pump happens all the time. A driver who has to stop and work out where it goes normally tops up the AdBlue side, from a bottle, and much less often. The error lives in that gap. ## How does AdBlue in your diesel tank occur in Crawley Hill? Rarely is it carelessness: usually three things coincide. To start with, the warning. Low AdBlue brings a warning from the vehicle, and letting it run dry means limp mode — hence a hurried top-up, perhaps before work off Church Hill, perhaps outside The Claude du Vall on the way home that evening. The old car's filler is where your hand goes — yet a hire car, a new car or a company car keeps the fillers elsewhere. That's the second factor: a new motor. No part stops the tip after it has started, because a bottle with a spout goes into a diesel filler as readily as an AdBlue one. The bottle fits. The same few seconds decide it, in the middle of Crawley Hill or out in Camberley. ## How to tell the AdBlue filler from the diesel one Before you pour anything, whether on a drive in York Town or a forecourt around Crawley Hill, check these. They take a few seconds. - Position misleads; the cap doesn't. AdBlue ones tend to be blue or carry the word "AdBlue" — diesel caps normally do not. - The size. On plenty of motors the AdBlue filler neck is the smaller of the two. - Open the filler flap and check for a label — plenty of vehicles mark which goes in each inlet just there. - In the boot or under the bonnet: that is where your filler sits if it is not by the diesel cap, and the handbook says which. - The previous driver will know. Check as you pick up a rental or company car — from Camberley's car park, say — not when the light comes on. ## Keeping AdBlue out of the diesel tank when you top up For the day the light appears — wherever you are in Surrey — a simple routine to follow. - Not in a rush on the side of Crawley Hill, not on a slope, not with the engine running: park and switch off first. - Silly as it sounds, speaking "AdBlue" aloud while you unscrew the cap works — after you have located your filler and read the cap. - The diesel cap stays on. Where both share a flap, confirm it is shut before lifting the bottle. - Stop when the tank is topped up or the bottle is empty; until then, tip slowly through its own spout. - Close the cap, then check once more — making sure your diesel cap stayed closed the whole time. Only then, start the vehicle. Stop there if you find, at stage two or three, that you have already poured into your diesel side. Leave out step five entirely. ## Put AdBlue in your diesel tank in Crawley Hill already? Brief list, then. Top of that: the motor remains unstarted. Keep the ignition off too, since on plenty of diesels switching it on by itself runs the fuel pump. Filling up with diesel will not thin it: rather than mixing, AdBlue drops to the base of the tank, just where the fuel is taken from. If you are at a forecourt, whether it is the Texaco or the Esso, ask the staff to help roll your car clear of the pump. Leave it where it is if you're on your own driveway in Crawley Hill. When the engine has run by now, stop somewhere safe and turn it off. On the M3, under a mile from Crawley Hill, that means the next exit. About how far did it go? Crossing Crawley Hill is less a job than a run of under 50 miles to Westminster, so tell us. ## What occurs when our engineers arrive around Crawley Hill Outside Crawley Ridge Junior School, close to St Paul's or on your own driveway: wherever the car has stopped, our technicians come to it. What liquid went in, the quantity, and whether it ran: our technicians ask because those answers set both work and quote. You hear that quote by phone, before anyone sets off. Then your tank is emptied and the system rinsed thoroughly. Not like petrol, AdBlue leaves crystals and eats at certain fuel-system metals, and neither clears out by itself. That is why it counts more. The filter is flushed, or replaced where it needs to be; fresh diesel goes in; and the vehicle is tested. Next our engineers start it and confirm it runs properly before leaving. Unstarted vehicles mostly mean a half-hour job after the moment we arrive. The kit is safe on a live filling station, and hushed enough for a driveway late at night. Payment happens on the day, not upfront, and you receive the paperwork an insurer wants: an engineer's report and a VAT invoice. It's worth checking your insurance while we travel to you: misfuelling cover is included with plenty of policies. ## About Crawley Hill, for a moment Crawley Hill is a suburban area in Surrey, situated inland at an elevation of around 115 metres. Crawley Hill lies approximately 28.6 miles from London and is near several other communities, including Camberley and Heatherside. Crawley Hill is characterised by its predominantly detached housing stock, reflecting the area's residential nature. Crawley Hill is also close to Frimley Ridge, a nearby geographical feature. ## AdBlue drains around Crawley Hill, and Surrey beyond Frimley Ridge and Heatherside are among the places around Crawley Hill, a residential suburb, that the same vans cover, over GU postcodes. A postcode starting GU15 2 gets the van to you fastest. Your car stays where it is. Anywhere it stands — beside The Obelisk, on a lay-by heading to Camberley Park, on a drive — that's where it is drained. Ring and ask rather than guessing if you're near a border, or somewhere hard to explain, like the back of High Cross Church. ## For Crawley Hill drivers, the short version Before you pour, read the cap. Still AdBlue in the diesel tank? Petrol in Diesel can drain it wherever it is, anywhere in Surrey: switch it off and ring 0333 366 0103.