--- title: Merrow: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/merrow-surrey/ location: Merrow county: Surrey latitude: 51.252770 longitude: -0.538570 service: AdBlue in a Diesel Tank updated: 2026-10-27 --- # AdBlue in a Diesel Tank in Merrow: Why It Occurs and How to Prevent It AdBlue already in your diesel tank? Then set this page down a moment, leave the ignition and motor off, and ring 0333 366 0103. Usually, when the motor has not run, it is emptied and fully purged where the car is in Merrow. Reading in advance? Then what follows covers why it happens and how to prevent it ever happening. ## AdBlue in a diesel motor, and its separate tank Many modern diesels on the roads round Merrow and Slyfield carry two liquids, not one. Diesel goes to your motor. AdBlue goes to your exhaust, where it is sprayed into the gas to fresh it, and it lives in a tank of its own. There's a filler for each tank. Under one flap, next to each other: that is the layout on a lot of vehicles. On others, AdBlue's filler sits beneath the bonnet or in the boot instead. The diesel side is filled at the pump all the time. The AdBlue side is fuelled far less regularly, usually from a bottle, and normally by a person who has to stop and think where it goes. That gap is where the error lives. ## Merrow: how AdBlue in the diesel tank takes place Three things tend to come together, and carelessness is seldom one of them. Hurry follows from the warning. The vehicle tells you as AdBlue runs low, and an empty tank puts the vehicle into limp mode — so the top-up gets done quickly, before work on a drive off Hareward Road, or on the way home in the car park outside Anchor and Horseshoes. Next, your hand goes for the cap it knew on the old vehicle — because a hire car, a new car or a company car places the fillers where your last one did not. No part halts the tip after it has started, since a bottle with a spout goes into a diesel filler as readily as an AdBlue one. The bottle fits. Whether it happens in Bushy Hill or the middle of Merrow, it is the same few seconds. ## Telling the AdBlue filler from the diesel filler Whether a Merrow forecourt or a drive over in West Clandon, take a few seconds on these before any is poured in. - Read the cap instead of going by where it sits: AdBlue ones are often blue or marked "AdBlue", and diesel caps usually aren't. - Check the size: the smaller neck is, on many vehicles, the AdBlue one. - Check inside your fuel flap: plenty of vehicles carry a label there showing which fuel goes where. - Cannot find it next to the diesel inlet? Then check below the bonnet or inside the boot — the handbook says where. - Ask the person who drove it last — before you leave, not when the light comes on — when you collect a hire or company car from somewhere like the car park at London Road (Guildford). ## Topping up AdBlue without it reaching your diesel tank Wherever in Surrey the light comes on, here is a routine for that day. - Park then switch off. Not on a slope, not with your motor running, and not in a rush on the side of Ashbury Crescent. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds silly and it works. - The diesel cap remains on. Where both sit under a flap, make sure it is closed before the bottle comes up. - Using the bottle's own spout, tip slowly — and stop when it is full or the bottle is empty. - Only then, start the car: close the cap, check once more, and make sure your diesel cap was never opened. If at stage two or three you find you have already poured into the diesel side, stop there. Don't go on to step five. ## Put AdBlue in your diesel tank around Merrow already? What follows is a short order of things, beginning with not starting your engine. Leave the ignition off too, because on plenty of diesels switching it on alone starts the pump. Do not top up with diesel to thin it: AdBlue doesn't mix with diesel, it sinks to the bottom of your tank, where your fuel is sucked from. If you're on a forecourt, whether it's the BP or the Sainsbury's, ask the staff to help push the car away from the petrol pump. At home in Merrow? So the car stays put. When the motor has run by now, stop somewhere safe then switch it off. On the M25, under 10 miles from Merrow, that means the next junction. A short hop across Merrow is a smaller job than a run towards Westminster, under 25 miles away, and so tell us roughly how far it went. ## What takes place when we turn up around Merrow Our technicians come to the vehicle wherever it has stopped, whether that is outside Merrow CofE Controlled Infant School, close to Bushy Hill Community Centre or on your own drive. The answers settle the work and our price, and so we ask what went in, roughly how much, and whether it's run. You hear that price by phone, before anyone heads out. Emptying that tank comes next, followed by a thorough flush of the system. With AdBlue that matters more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, so it does not wash out on its own. Testing is last: before that, clean diesel goes in, and the filter is cleaned or replaced if necessary. The engine is fired up next and tested to be sure it runs smoothly, all before our technicians go. With pumps safe on a busy forecourt and quiet enough to use outside a house at night, most jobs in which the engine has not run need roughly half an hour once we arrive. No money upfront; you settle up on the day. At the end, the VAT invoice and a report from the engineer go to you for the insurer. Misfuelling cover is included in plenty of insurance policies — so use the wait to look at yours. ## About Merrow itself Merrow is a suburban area in Surrey, situated approximately 25 miles southwest of central London. Merrow occupies a relatively low-lying area at around 63 metres above sea level, near the neighbouring communities of Bushy Hill and Burpham. Merrow has a mix of housing types, but semi-detached homes are particularly prevalent in the area. Merrow is also close to the larger settlement of Guildford, although its nearest city is Westminster, about 24.7 miles away. ## AdBlue drains across Surrey, Merrow included Burpham and Abbotswood are among the towns near Merrow, a residential suburb, that the same teams cover, throughout GU postcodes. Fastest of all: give a GU4 7 postcode to the van. The car does not need to shift. A drive, a lay-by on the way to Bushy Hill Park, a side street near Church of the Holy Spirit: our engineers drain the vehicle where it stands. Ring and ask instead of assuming if you're near a border, or somewhere hard to explain, like the back of Merrow Methodist Church. ## For Merrow drivers, the short version First, the cap; after that, the pour. Even so AdBlue in your diesel tank? Petrol in Diesel will drain it where it stands, wherever across Surrey: switch it off then phone 0333 366 0103.