--- title: Explained: AdBlue in a Diesel Tank Garvagh canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/garvagh-county-londonderry/ location: Garvagh county: County Londonderry latitude: 54.981750 longitude: -6.684490 service: AdBlue in a Diesel Tank updated: 2026-10-27 --- # Avoiding AdBlue in a Diesel Tank in Garvagh: Why It Occurs If AdBlue is already in your diesel tank, stop reading for a moment: leave the engine and the ignition off then ring 0333 366 0103. Usually, if your motor has not run, it's drained and thoroughly cleaned where your vehicle sits in Garvagh. The rest of this page covers why it takes place and how to make sure it does not — handy if you are reading before it has happened. ## Two fillers, two tanks: AdBlue in a diesel car Diesel goes to the engine — but plenty of modern diesels driven around Garvagh and Ringsend hold another liquid as well. The exhaust, not the motor, is where AdBlue goes: sprayed into the fumes to fresh them, from its own tank. There's a filler on every tank. Other vehicles keep the AdBlue filler in the boot or under the bonnet; plenty of others have both side by side under one flap. Topping up your diesel side at the petrol pump goes on constantly. The AdBlue side is filled far less frequently, usually from a bottle, and usually by somebody who has to stop and think where it goes. The slip lives in that gap. ## How AdBlue in your diesel tank happens in Garvagh Rarely is it carelessness: usually three things line up. On a driveway off Wallace Cottages before work, or in the car park outside the pub in the village on the way home: that is where the hurried top-up happens. Why the rush? As AdBlue runs low the vehicle warns you, and if it is gone, limp mode kicks in. Then, your hand goes for the cap it knew on the old vehicle — since a rental car, a new car or a company car places the fillers somewhere your last one didn't. A spout-topped bottle finds no obstacle at a diesel filler any more than at an AdBlue one. So the tip, after started, carries on. Ballerin or the middle of Garvagh: it takes the same few seconds either way. ## The AdBlue filler and your diesel filler: telling them apart Before you tip anything, whether on a drive in Swatragh or a forecourt around Garvagh, check these. They take a few seconds. - Where it sits can mislead; the cap doesn't. AdBlue caps are often blue or carry the name "AdBlue" — diesel ones usually do not. - The size. On many motors the AdBlue filler neck is the smaller of the two. - Check inside the fuel flap: plenty of vehicles carry a label there showing which fuel goes where. - Can't see it beside your diesel filler? In that case look below the bonnet or in the boot — the handbook says where. - The person who drove the vehicle last. On a hire or company car picked up from somewhere like the car park outside the nearest station, ask before you leave, not when the light comes on. ## Keeping AdBlue out of the diesel tank when you top up Anywhere in County Londonderry the light comes on, this is a routine for the day. - Not in a rush on the side of Dunaverty Court, not on a slope, not with the motor running: park then switch off properly. - Say "AdBlue" out loud as you unscrew the cap, after finding the AdBlue filler and read it. Silly, yes, yet it does the trick. - If both sit under one flap, check the diesel cap is still closed before you lift the bottle — and leave the vehicle on. - Tip slowly, using the bottle's own spout. Stop when it's full or when the bottle is empty. - Only after that, start the vehicle: close the cap, check a second time, and make sure your diesel cap was never opened. Find at step two or three that it has already gone into your diesel side? Then stop right there. Skip stage five entirely. ## Garvagh: already put AdBlue in your diesel tank? What follows is a short order of things, beginning with not starting your engine. Keep your ignition off too, because on plenty of diesels switching it on by itself starts your pump. Topping up with diesel will not thin it: rather than mixing, AdBlue drops to the bottom of your tank, right where the fuel is drawn from. The staff at the nearest petrol station, another forecourt nearby or another forecourt will normally lend a hand to push the vehicle clear if asked. Leave it where it is if you are on your own drive in Garvagh. If your motor has already run, stop as soon as it is safe and switch off. The next exit is where to leave when you're on the M77, over 50 miles from Garvagh. About how far did it go? Hopping across Garvagh is smaller work than a run of under 25 miles to Derry, and so say. ## What happens when we arrive in Garvagh Outside the local primary school, close to the centre or on your own drive: wherever the car has stopped, we come to it. Which fluid got in, the quantity, and if it ran: our technicians ask because the replies decide the work and quote. Nobody sets off before you have heard our price over the phone. Next: a drain, then a thorough flush of the whole system. AdBlue crystallises and is corrosive to some of the metals in a fuel system, so it does not wash out on its own — which is why that counts more with AdBlue than with petrol. The filter flushed or, if needed, swapped; fresh diesel in; then a test of the car. Your engine is started next and checked to confirm it runs properly, all before our technicians head off. If the motor hasn't run, most jobs take about half an hour once we are there, using pumps that are safe on a busy forecourt and quiet enough to use outside a house at night. Your insurer usually wants the engineer's report and the VAT invoice, and you get both at the end. Payment is on the day, with no deposit. It's worth checking your insurance while we travel to you: misfuelling cover comes with plenty of policies. ## About Garvagh and where it is Garvagh is a small locality in County Londonderry, situated inland at an elevation of 71 metres, approximately 24.7 miles from Derry. Garvagh is characterised by its predominantly detached housing stock and a population of around 963 residents. Garvagh sits near the settlements of Ballerin, Aghadowey, and Kilrea, in a region of Northern Ireland known for its rural landscapes. ## AdBlue drains across County Londonderry, Garvagh included Aghadowey and Kilrea are among the towns around Garvagh, a small village, that the same vans cover, throughout BT postcodes. Quickest of all: give a BT51 5 postcode to the van. The car doesn't need to move. A drive, a lay-by on the way to the green space at the edge of the village, a side street near a street just off the centre: our technicians drain it where it stands. Ring and ask rather than guessing if you are near a border, or somewhere hard to explain, like the back of the far end of the built-up part. ## For Garvagh motorists, the short version Before you tip, read the cap. Petrol in Diesel empties it where it stands, anywhere around County Londonderry, if AdBlue has gone in the diesel tank anyway — and so leave the vehicle off then ring 0333 366 0103.