--- title: AdBlue in a Diesel Tank Colebrook: Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/colebrook-devon-ex15-1/ location: Colebrook county: Devon latitude: 50.845640 longitude: -3.411650 service: AdBlue in a Diesel Tank updated: 2026-10-24 --- # Colebrook: How Does AdBlue End Up in a Diesel Tank, and How Do You Avoid It? Keep the engine and ignition off and phone 0333 366 0103 first — reading can wait if AdBlue is already in the diesel tank. Normally, when the motor hasn't run, it's drained and fully purged where your vehicle is in Colebrook. If you're reading before it has happened, the remainder of this page is about why it happens and how to make sure it does not. ## Why does AdBlue in a diesel car need its own filler? Not one fluid but two: that is how plenty of newer diesels around Colebrook and Westcott run, with diesel for the engine. Its own tank holds it, and from there it is sent to your exhaust, and there a spray treats the fumes. There is a filler for each tank. Under one flap, side by side: that is the layout on a lot of motors. On others, AdBlue's filler is beneath the bonnet or in the boot instead. The diesel side is fuelled at the pump all the time. Rarely filled, AdBlue normally goes in from a bottle, tipped by a driver who has to stop and think which cap to use. It is in that gap that the error lives. ## How does AdBlue in your diesel tank take place around Colebrook? Three things tend to line up, and carelessness is rarely one of them. To start with, the warning. Low AdBlue triggers a message from your car, and letting it run dry leads to limp mode — hence a hurried top-up, perhaps before work off Bowhill, or at Bell Inn on the way home after work. Then your car is strange. A hire car, a new vehicle or a company car puts the fillers where your last one did not, and your hand gets to for the cap it would have used on the old one. No part stops the pour after it has started, because a bottle with a spout goes into a diesel filler as easily as an AdBlue one. The bottle fits. Whether it occurs in Knowle or the middle of Colebrook, it's the same few seconds. ## Which filler is for AdBlue, and which for diesel? Look at these before pouring, on a forecourt in Colebrook or a drive over in Bradninch. Seconds, no more. - Colour and marking: an AdBlue cap is frequently blue, or says "AdBlue", where a diesel cap normally does not. Go by the cap, not where it sits. - Look at the size: the smaller filler neck is, on plenty of motors, the AdBlue one. - A label inside the fuel flap frequently says which fuel goes where, on many cars. Check for it. - In the boot or under the bonnet: that's where the filler sits if it's not by the diesel cap, and the handbook tells you which. - The previous driver knows. Ask as you collect a hire car or fleet car — at Tiverton Parkway's car park, perhaps — not when the light appears. ## AdBlue top-ups that never reach your diesel tank When the light goes on, anywhere around Devon, use this routine. - Turn off once parked — level ground, engine stopped, and never rushed by Catherine Close on the verge. - Say "AdBlue" out loud as you unscrew the cap, once finding the AdBlue filler and reading 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. - Tip slowly, using the bottle's own spout. Stop when it is full or when the bottle is empty. - Close the cap and check once more. Make sure the diesel cap was never opened. Only then start your car. Discover during the second or third step that AdBlue went in the wrong tank? That's where you stop. Never carry on to step five. ## Put AdBlue in the diesel tank around Colebrook already? What follows is a short order of things, starting with no 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 dilute it: AdBlue doesn't mix with diesel, it sinks to the bottom of your tank, where the fuel is sucked from. Ask the staff to help push the vehicle clear of the pump if you're on a forecourt — the Gulf, the Tesco or anywhere else. On your own drive in Colebrook? So the vehicle stays put. Where the engine has been run already, pull over somewhere safe and turn the car off. The next junction means the place to leave when you're on the M5, under a mile from Colebrook. A short hop across Colebrook is a smaller job than a run towards Exeter, under 15 miles away, and so tell us roughly how far it went. ## When our technicians arrive around Colebrook, what occurs? Our technicians come to the vehicle wherever it has stopped, whether that's outside Willowbank Primary School, near Culm Vale Bowling Club or on your own drive. Our technicians ask what went in, roughly how much, and whether it's run, because the answers settle the work and the quote. Nobody heads out until you have had our price by phone. Draining your tank comes next, then a full 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. A test is at the end: before that, fresh diesel is added, and the fuel filter is flushed or changed as needed. We do not leave until it has been fired up and is running correctly. Most jobs are finished in about half an hour once we get there, provided the engine hasn't run — and the pumps our engineers use are safe on a live forecourt and quiet at night beside a house. Your insurer will ask for an engineer's report and your VAT invoice, and you get both once this job is done. Payment comes on the day, with no deposit. Misfuelling cover is part of plenty of insurance policies — and so make use of the wait to look at yours. ## About Colebrook and where it is Colebrook is a small hamlet situated on the riverside in Devon, with a relatively low elevation of 91 metres. Colebrook lies close to the city of Exeter, approximately 10 miles away, and is near other local places such as Knowle and Ponsford. Colebrook has a population of around 538 people, predominantly living in semi-detached housing. Colebrook is located in the South West region of England, about 149 miles from London. ## AdBlue drains around Colebrook, and Devon beyond Ponsford and Cullompton are among the places near Colebrook, a rural hamlet, that the same vans cover, over EX postcodes. Fastest of all: give a EX15 1 postcode for the van. The car doesn't need to shift. We drain it where it is — a side street near Cullompton Scout Group, a lay-by on the way to The Green, a driveway. Assuming doesn't help at the back of St Boniface, on a boundary, or somewhere awkward to describe; ring and check. ## For Colebrook drivers, the short version Tip no AdBlue till you have read the cap. Petrol in Diesel drains it on the spot, anywhere in Devon, if AdBlue has gone in the diesel tank anyway — so leave the car off then ring 0333 366 0103.