--- title: AdBlue in a Diesel Tank Feeny: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/feeny-county-londonderry/ location: Feeny county: County Londonderry latitude: 54.893000 longitude: -7.022000 service: AdBlue in a Diesel Tank updated: 2026-10-20 --- # Avoiding AdBlue in a Diesel Tank in Feeny: Why It Occurs If AdBlue is already in your diesel tank, stop reading for a moment: leave the motor and the ignition off then call 0333 366 0103. Caught before the motor runs, it is generally a drain and a thorough flush, done where the vehicle is around Feeny. The remainder of this page covers why it occurs and how to make sure it doesn't — useful if you're reading before it has happened. ## Why does AdBlue in a diesel motor need its own filler? Plenty of current diesels on the roads round Feeny and Derrynaflaw carry two liquids, not one. Diesel goes to your motor. AdBlue goes to the exhaust, where it is sprayed into the gas to clean it, and it lives in a tank of its own. Separate tanks, different fillers. Other cars keep the AdBlue filler in your boot or under the bonnet; a lot of others have the two together behind one flap. Filling your diesel side at the pump goes on all the time. The AdBlue side is topped up far less commonly, normally from a bottle, and usually by someone who has to stop and think where it goes. That gap is where the error lives. ## How does AdBlue in your diesel tank happen around Feeny? Carelessness seldom causes it. What does is three things coming up at once. First, the warning. Low AdBlue brings a warning from your car, and running dry leads to limp mode — so a rushed top-up, perhaps before work off Rock Street, or outside the pub in the village on the way home that evening. Then, the hand goes for the cap it would have used on the old motor — because a rental car, a new car or a company car puts the fillers where your last one did not. No part stops the pour after it has started, since a bottle with a spout goes into a diesel filler as readily as an AdBlue one. The bottle fits. The same few seconds settle it, in the middle of Feeny or out in Banagher. ## The AdBlue filler and your diesel filler: telling them apart Be it a Feeny forecourt or a drive out in Ballyrory, spend a few seconds over these before anything goes in. - Blue and lettering: an AdBlue cap is frequently blue, or says "AdBlue", where a diesel cap normally doesn't. Go by the cap, not where it sits. - Check the size: the smaller neck is, on many motors, the AdBlue one. - Open the filler flap and check for a label — many cars mark what belongs in each inlet just there. - The handbook. If the filler is not by the diesel cap, it is in your boot or under the bonnet, and the handbook says which. - Picking up a hire or company car, perhaps at the car park outside the nearest station? Ask whoever drove the vehicle last before leaving, not when the light goes on. ## Keeping AdBlue out of the diesel tank when you top up A routine for the day the light comes on, wherever in County Londonderry that is. - Park then switch off. Not on a slope, not with your engine running, and not in a rush on the side of Crom Street. - 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 stays on. Where both sit under a flap, make sure it is closed before the bottle comes up. - Stop once your tank fills or the bottle is empty; before that, pour slowly using the own spout. - Before starting the vehicle, close the cap and look a second time that the diesel cap was never came off. Stop there if you find, at step two or three, that you have already poured into your diesel side. Never go on to step five. ## Put AdBlue in your diesel tank in Feeny already? What follows is a short order of things, beginning with not starting the motor. On many diesels your ignition alone runs the fuel pump, so do not switch the vehicle on. Don't 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. Ask the attendants to help push the vehicle away from the pump if you are at a forecourt — the the nearest petrol station, the another forecourt nearby or anywhere else. If you are on your own drive around Feeny, leave the car where it stands. Already started? Pull over when it is sensible, then turn off. Come off the M77 — over 50 miles out of Feeny — at the next exit. Distance matters — a short hop across Feeny makes a smaller job than heading under 15 miles towards Derry — so tell us roughly how far it went. ## Feeny: what happens when our engineers turn up Wherever the vehicle has stopped, be it by the local primary school, near the centre or at home, the van comes to it. Those answers settle the work and our price, so our engineers ask what was put in, about how much, and whether it has run. You hear that quote on the phone, before anybody heads out. Then that tank is emptied and your system cleaned thoroughly. AdBlue crystallises and is corrosive to some of the metals in a fuel system, and so it doesn't wash out on its own — which is why that matters more here than with petrol. A test is last: before that, clean diesel is added, and the filter is flushed or changed if necessary. After that we fire it up and make sure it runs properly before we go. With pumps safe on a busy forecourt and quiet enough for use outside a house at night, most jobs where your engine has not run take about half an hour once our engineers are there. No money upfront; you settle up on the day. Afterwards, a VAT invoice and a report from the engineer go to you for your insurer. Many insurance policies include misfuelling cover, and so it's worth checking yours while we're on the way. ## About Feeny and where it is Feeny is a small locality in County Londonderry, situated inland at an elevation of 149 metres, approximately 13 miles from Derry. Feeny lies near the villages of Banagher and Straidarran, and is characterized by its semi-detached housing stock. Feeny is a relatively small community, with a population of around 702 people, and is located about 368 miles northwest of London. ## Feeny and County Londonderry: AdBlue drains across the area Feeny is a small village, and our teams that cover it also work the places around it, Straidarran and Park among them, across the BT postcode area. A postcode starting BT47 4 gets our van to you fastest. The car does not need to move. Anywhere it stands — beside a street just off the centre, on a lay-by en route to the green space at the edge of the village, at home — that is where it is emptied. Awkward to explain, like the back of the far end of the built-up part? By a county line? Checking beats guessing, so phone. ## For Feeny motorists, the short version Always, the cap; then, the pour. If AdBlue has gone in the diesel tank all the same, leave it off and call 0333 366 0103. Petrol in Diesel empties it where it stands, anywhere in County Londonderry.