--- title: AdBlue in a Diesel Tank Comiston? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/comiston-city-of-edinburgh/ location: Comiston county: City of Edinburgh latitude: 55.901990 longitude: -3.207350 service: AdBlue in a Diesel Tank updated: 2026-10-19 --- # Preventing AdBlue in a Diesel Tank in Comiston: Why It Occurs Leave your motor and ignition off then phone 0333 366 0103 first — reading can wait if AdBlue is already in the diesel tank. Caught before your engine runs, it is normally a drain and a thorough flush, done where your car is in Comiston. The remainder of this page explains why it happens and how to ensure it does not — handy if you are reading ahead of time. ## AdBlue in a diesel car: two tanks, two fillers Many modern diesels around Oxgangs, as well as Comiston, run on two liquids; your engine takes just the diesel. Its own tank holds it, and from there it is sent to your exhaust, and there spraying cleans the fumes. Separate tanks, separate fillers. Under one flap, next to each other: that's the arrangement on many vehicles. On others, AdBlue's filler is under the bonnet or in your boot instead. Filling your diesel side at the petrol pump happens constantly. The AdBlue side is fuelled far less commonly, normally from a bottle, and normally by someone who has to stop and think where it goes. Mistakes happen in the gap between them. ## Comiston: how AdBlue in your diesel tank happens Seldom is it carelessness: normally three things coincide. The warning comes first. As AdBlue runs low the vehicle tells you, and if it runs out altogether, the vehicle drops into limp mode. So the top-up is done in a hurry: on a driveway off Fairmile Avenue before work, or in the car park at Hunter's Tryst on the way home. Then the car is new. A hire car, a new car or a company car puts the fillers where your last one did not, and the hand hits for the cap it would have used on the old one. A spouted bottle meets no obstacle at a diesel filler any more than at an AdBlue one. So the tip, once started, carries on. Fairmilehead or the heart of Comiston: it takes the same few seconds either way. ## The AdBlue filler and the diesel filler: telling them apart Before you tip anything, whether on a driveway in Greenbank or a forecourt in Comiston, check these. They take a few seconds. - The cap. The AdBlue cap is frequently blue, or marked "AdBlue". Your diesel cap normally is not. Read it rather than going by position. - Plenty of cars fit AdBlue the smaller filler of the two. - Open the flap and check for a label — plenty of motors show what goes in which filler right there. - In your boot or under the bonnet: that is where your filler sits if it is not by your diesel cap, and the handbook tells you which. - Check with the person who drove it last — before you leave, not when the light comes on — if you collect a hire or company car from somewhere like the car park outside Slateford. ## Topping up AdBlue without it reaching the diesel tank A routine for the day the light comes on, wherever in City of Edinburgh that is. - Not in a rush on the side of Buckstone Terrace, not on a slope, not with your engine running: park then switch off properly. - Say "AdBlue" out loud as you unscrew the cap, once finding the AdBlue filler and read it. Daft, perhaps, yet it does the trick. - Leave the diesel cap on. If both sit under one flap, check your diesel cap is still closed before you lift the bottle. - Slowly does it, through the bottle's own spout, till it's full or the bottle runs out. - Only then, start the vehicle: close the cap, check again, and make sure your diesel cap was never opened. Find at step two or three that it has already gone into the diesel side? Then stop right there. Leave out stage five altogether. ## Put AdBlue in the diesel tank around Comiston already? Then the order of things is short. Do not start your engine. Leave the ignition off as well, since on many diesels switching it on by itself starts the pump. Don't top up with diesel to dilute it: AdBlue doesn't mix with diesel, it sinks to the bottom of the tank, where the fuel is pulled from. At a forecourt — Esso, Shell or any other — the staff will normally help roll the vehicle clear, when you ask. Your own driveway in Comiston is the place it stays. If the motor has already run, stop as soon as it is safe and switch off. On the M8, under 5 miles from Comiston, that means the next junction. Roughly how far did it go? Crossing Comiston is smaller a job than a trip of under 5 miles towards Edinburgh, so say. ## Comiston: what occurs when our technicians arrive Our engineers come to the vehicle wherever it has stopped, whether that is outside the local primary school, close to Fairmilehead Parish Church or on your own drive. We ask what was put in, about how much, and if it's run, since the replies determine the work and our price. On the call itself, you hear the price — ahead of dispatch. The fuel system is then flushed thoroughly, after that tank is cleared. Unlike petrol, AdBlue leaves crystals and eats at some fuel-system metals, and neither washes out unaided. That is why it matters more. The filter is cleaned, or replaced where it needs to be; fresh diesel goes in; and the vehicle is tested. Then our engineers fire it up and make sure it runs smoothly before we leave. Most jobs are done in roughly half an hour after our engineers get there, provided your motor hasn't run — and the pumps we use are safe on a busy forecourt and quiet after dark beside a house. Paying happens on the day, not upfront, and you are given the paperwork an insurer asks for: an engineer report and a VAT invoice. While we travel, have a look at your policy; plenty include cover for misfuelling. ## About Comiston Comiston is a suburban area in the City of Edinburgh, situated near the River Almond and overlooking the surrounding countryside. Comiston sits at an elevation of 182 metres, with detached housing being the predominant type of accommodation in the area. Comiston is located close to several nearby places, including Fairmilehead, Lothianburn, and Swanston, and is approximately 3.6 miles from Edinburgh city centre. ## Comiston and City of Edinburgh: AdBlue drains across the area Lothianburn and Swanston are among the places around Comiston, a residential suburb, that the same vans cover, throughout EH postcodes. Quote a postcode that starts EH10 6, and the van arrives fastest. Moving your car is not needed. We drain it where it is — a side street near Caiy Stane, a lay-by on the way to Bellrock Park, a drive. Assuming doesn't help at the back of St Fillan, close to a boundary, or somewhere awkward to describe; phone and ask. ## Comiston motorists: the short version Always, the cap; after that, the pour. AdBlue in the diesel tank after all? Keep the vehicle switched off and phone 0333 366 0103; Petrol in Diesel drains it on the spot, throughout City of Edinburgh.