--- title: AdBlue in a Diesel Tank Mousehole? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/mousehole-cornwall/ location: Mousehole county: Cornwall latitude: 50.081960 longitude: -5.539530 service: AdBlue in a Diesel Tank updated: 2026-10-19 --- # Mousehole: How Does AdBlue End Up in a Diesel Tank, and How Do You Avoid It? AdBlue already in your diesel tank? In that case put this page down a moment, leave the ignition and motor off, then phone 0333 366 0103. Normally, if the engine has not run, it is drained and thoroughly flushed where the car is in Mousehole. If you are reading before it has happened, the remainder of this page is about why it occurs and how to make sure it does not. ## Why does AdBlue in a diesel motor need its own filler? Plenty of current diesels on the roads about Mousehole and Sheffield carry two liquids, not one. Diesel goes to the motor. Kept in a tank of its own, AdBlue is sprayed into your exhaust gas and cleans it. There is a filler for each tank. Some motors put the AdBlue filler in the boot or under the bonnet; a lot of others have both together behind one flap. Diesel gets filled on every filling station visit, again and again. Someone who has to stop and think where it goes usually tops up the AdBlue side, from a bottle, and far less regularly. That gap is where the mistake lives. ## How does AdBlue in the diesel tank take place around Mousehole? It's seldom carelessness. Three things tend to line up. To start with, the warning. Low AdBlue brings a warning from the car, and running out leads to limp mode — so a hurried top-up, perhaps before work off Chapel Street, or outside The Ship Inn on the way home after work. 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 your hand gets to for the cap it would have used on the old one. And the bottle fits. A bottle with a spout goes into a diesel filler as easily as an AdBlue one, and so nothing stops the pour after it has started. Trevithal or the heart of Mousehole: it takes the same few seconds either way. ## How to tell the AdBlue filler from the diesel one A few seconds is all these take — so run through them before you pour anything, on a drive in Castallack or a forecourt in Mousehole. - Colour and marking: an AdBlue cap is regularly blue, or says "AdBlue", where a diesel cap normally doesn't. Trust the cap, not where it sits. - Check the size: the smaller neck is, on plenty of cars, the AdBlue one. - A label inside your fuel flap often shows which fuel goes where, on plenty of cars. Check for it. - In the boot or under the bonnet: that's where your filler is if it's not by your diesel cap, and the handbook tells you which. - The person who drove it last. On a hire or company car collected from somewhere like the car park outside Penzance, ask before you leave, not when the light comes on. ## AdBlue top-ups that never reach the diesel tank Anywhere in Cornwall the light comes on, this is a routine for that day. - Pull in somewhere level, engine off, with time in hand — not hurried on the side of Raginnis Hill. - Say "AdBlue" out loud as you unscrew the cap, once you find the AdBlue filler and reading it. Silly, yes, yet it works. - If both sit under one flap, check your diesel cap is still closed before you lift the bottle — then leave the vehicle on. - Slowly is best, through the bottle's own spout, till it's full or the bottle is empty. - Close the cap and check a second time. Make sure your diesel cap was never opened. Only then start the vehicle. Spot at step two or three that it has already gone into your diesel side? Then stop just there. Never carry on to step five. ## Already put AdBlue in your diesel tank in Mousehole? Don't start your motor: that is where the short order of things begins. On many diesels the ignition alone runs the fuel pump, so do not switch the vehicle on. AdBlue doesn't mix with diesel — it sinks to the bottom of that tank, where your fuel is pulled from — so don't top up with diesel to dilute it. If you're at a forecourt, whether it's the Texaco or the Tesco, ask the attendants to help push the car clear of the petrol pump. On your own drive around Mousehole? So the car stays where it is. Stop as soon as it is safe and switch off, if the engine has already run. Leave the M5 — over 50 miles out of Mousehole — at the first junction. Tell us roughly how far it went: a run towards Truro, under 50 miles away, is a bigger job than a short hop across Mousehole. ## What occurs when our engineers arrive in Mousehole Our van comes to the car wherever it stopped — your own drive, near Wesleyan Chapel, or by Mousehole School. The replies settle the work and our price, and so our engineers ask what was put in, roughly how much, and if it has run. That price comes over the phone, ahead of any van leaving. After that: draining, then a thorough flush of the entire 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. Testing is last: before that, clean diesel is added, and the fuel filter is flushed or replaced as needed. We don't leave until it has been started and is running smoothly. Most jobs are finished in about half an hour once our engineers get there, provided the motor has not run — and the pumps our technicians use are fine on a busy forecourt yet quiet at night beside a house. Paying is on the day, not upfront, and you are given the documents your insurer asks for: an engineer report and a VAT invoice. While we travel, take a look at your policy; many include cover for misfuelling. ## About Mousehole Mousehole is a small coastal village in Cornwall, situated on the southern coast of the peninsula, with a population of around 545 people. Mousehole sits at a low elevation of 14 metres, looking out over the sea, and is characterized by its predominantly detached housing stock. Mousehole is located near several other small settlements, including Trevithal, Raginnis, and Paul, and is about 25 miles from the city of Truro. Mousehole remains a quiet and secluded community, despite being within a day's travel of London, 256 miles to the east. ## AdBlue drains across Cornwall, Mousehole included Raginnis and Paul are among the places near Mousehole, a coastal village, that the same teams cover, throughout TR postcodes. The van reaches you fastest with a postcode starting TR19 6. The vehicle does not need to shift. Draining happens right there, whether a driveway, a road near Paul Labyrinth, or a layby on the way to Kemyel Crease. Awkward to pin down, like the back of Paul Church Hall? Close to a border? Checking is better than assuming, so phone. ## The short version for Mousehole drivers Always, the cap; after that, the tip. AdBlue in your diesel tank after all? Leave it off then call 0333 366 0103; Petrol in Diesel empties it on the spot, across Cornwall.