--- title: Cholsey: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/cholsey-oxfordshire/ location: Cholsey county: Oxfordshire latitude: 51.575060 longitude: -1.153360 service: AdBlue in a Diesel Tank updated: 2026-10-16 --- # Avoiding AdBlue in a Diesel Tank in Cholsey: Why It Happens AdBlue already in your diesel tank? Then put this page down for now, leave the ignition and engine off, then call 0333 366 0103. Caught before the motor runs, it is usually a drain and a thorough flush, done where the car is around Cholsey. Not happened yet? Further down, the rest of the page explains the why it happens and the how to avoid it altogether. ## AdBlue in a diesel vehicle, and its separate tank Plenty of newer diesels in Moulsford, like those in Cholsey, run on two liquids; your engine takes only the diesel. Stored in a tank of its own, AdBlue is sprayed into the exhaust stream to clean it. Separate tanks, different fillers. Under one flap, next to each other: that's the arrangement on a lot of motors. On others, AdBlue's filler sits beneath the bonnet or in the boot instead. The diesel side is fuelled at the pump all the time. The AdBlue side is fuelled far less regularly, usually from a bottle, and normally by someone who has to stop and think where it goes. The mistake grows in the gap between the two. ## Cholsey: how AdBlue in the diesel tank happens Three things tend to come together, and carelessness is seldom one of them. On a driveway off Ilges Lane before work, or in the car park outside Red Lion heading home: that's where the rushed top-up happens. Why the rush? As AdBlue gets low your car warns you, and if it's empty, limp mode follows. Then the vehicle is strange. A hire car, a new car or a company car puts the fillers where your last one didn't, and your hand gets to for the cap it would have used on the old one. Nothing halts the pour once it has started, since a bottle with a spout goes into a diesel filler as readily as an AdBlue one. The bottle fits. It's a few seconds, be it out in Winterbrook or right in the centre of Cholsey. ## Which filler is for AdBlue, and which for diesel? Look at these before pouring, at a forecourt in Cholsey or a driveway out in South Moreton. Seconds, no more. - Colour and lettering: an AdBlue cap is frequently blue, or says "AdBlue", where a diesel cap usually doesn't. Go by the cap, not its position. - Check the size: the smaller filler neck is, on many vehicles, the AdBlue one. - A label inside the fuel flap frequently shows which fuel goes where, on many motors. Look for it. - Cannot see it beside your diesel filler? Then check beneath the bonnet or inside your boot — the handbook says where. - The previous driver knows. Check when you pick up a rental or fleet car — from the nearest station's car park, perhaps — rather than once the warning comes on. ## Keeping AdBlue out of your diesel tank when you top up For the day the light appears — wherever you are around Oxfordshire — a routine to follow. - Park and switch off. Not on a slope, not with your engine running, and not in a rush on the side of Station Road. - Say "AdBlue" out loud as you unscrew the cap, after finding the AdBlue filler and reading it. Silly, perhaps, but it does the trick. - Leave the diesel cap on. If both sit under one flap, check the diesel cap is still closed before you lift the bottle. - Tip slowly, using the bottle's own spout. Stop when it's full or when the bottle is empty. - Only then, start the vehicle: close the cap, check once more, and make sure your diesel cap was never opened. If at step two or three you find you have already poured into your diesel side, stop there. Never carry on to stage five. ## Put AdBlue in the diesel tank in Cholsey already? The short order of things, starting with no starting the motor. The fuel pump runs on plenty of diesels as soon as your ignition goes on — and so leave it off. Diluting it with extra diesel won't work, because AdBlue sinks to the bottom instead of mixing — and that's where your fuel is sucked from. Ask the staff to help roll your car away from the pump if you're on a forecourt — the Texaco, the Esso or somewhere else. Your own drive around Cholsey is where it should stay. Where your engine has run already, pull over somewhere safe then turn the car off. On the M4, under 10 miles from Cholsey, that means the next exit. Roughly how far did it go? Hopping across Cholsey is less work than a run of under 15 miles to Oxford, so tell us. ## Cholsey: what takes place when we get there Outside Cholsey Primary School, close to Lawrence Hall or on your own drive: wherever the car has stopped, our engineers come to it. Our technicians ask what was put in, about how much, and if it's run, since those replies settle the work and our price. That price is given over the phone, before any van leaves. Then the tank is drained and the fuel system purged thoroughly. Much more than with petrol, it matters with AdBlue: crystals form, some metals corrode, and nothing washes away on its own, however long it sits. Your filter is flushed, or replaced where it needs to be; clean diesel goes in; and the car is tested. Before we leave, our technicians start the engine and make sure that it is running smoothly. With pumps fine on a busy forecourt and quiet enough to use outside a house at night, most jobs where your motor has not run need roughly half an hour after our technicians arrive. Nothing in advance; you settle up on the day. At the end, the VAT invoice and the report from the engineer are handed to you for the insurer. It is worth looking at your policy while we travel to you: misfuelling cover is included with plenty of policies. ## About Cholsey, briefly Cholsey is a village in south Oxfordshire, situated near the River Thames and approximately 13 miles south of Oxford. Cholsey sits in a low-lying area at an elevation of around 49 metres, with nearby villages including Winterbrook and North Stoke. Cholsey has a population of around 2098 people, predominantly living in semi-detached housing. Cholsey is located about 44 miles west of London, making it a commuter village with easy access to the capital. ## AdBlue drains across Oxfordshire, Cholsey included Throughout OX postcodes, the teams covering Cholsey — a rural village — work the surrounding spots too, Mongewell and North Stoke among them. Our van gets to you fastest with a postcode starting OX10 9. No need to shift your car. The drain takes place on the spot, be it a driveway, a road by Cholsy Free Church, or a lay-by on the way to Recreation Ground. Awkward to explain, like the back of Cholsey Pavilion? Close to a county line? Asking is better than assuming, so phone. ## Cholsey motorists: the short version Pour no AdBlue until you've read the cap. AdBlue in the diesel tank regardless? Leave it off then ring 0333 366 0103; Petrol in Diesel empties it where it stands, throughout Oxfordshire.