--- title: Explained: AdBlue in a Diesel Tank Tywardreath canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/tywardreath-cornwall/ location: Tywardreath county: Cornwall latitude: 50.357800 longitude: -4.692060 service: AdBlue in a Diesel Tank updated: 2026-10-08 --- # How It Happens and How to Avoid It: AdBlue in a Diesel Tank in Tywardreath AdBlue already in the diesel tank? Then put this page down a moment, leave the ignition and engine off, then call 0333 366 0103. A drain plus a full flush, carried out just where your vehicle stands in Tywardreath, is usually all it takes if caught before the engine runs. Reading in advance? Then the rest explains how it comes about and what to prevent it ever happening. ## AdBlue in a diesel vehicle: two tanks, two fillers Many newer diesels in Lanescot, like those in Tywardreath, carry on two liquids; the engine gets only the diesel. Kept in a tank of its own, AdBlue is fed into the exhaust gas and cleans it. Each tank has its own filler. On a lot of motors the two sit side by side under the same flap; on others the AdBlue filler is in the boot or under the bonnet. At the petrol pump, your diesel side gets filled constantly. A driver who has to stop and work out where it goes usually fills the AdBlue side, from a bottle, and far less often. The mistake lives in that gap. ## Tywardreath: how AdBlue in your diesel tank happens It is seldom carelessness. Three things tend to line up. Haste follows from the warning. The car warns you as AdBlue runs low, and an empty tank puts it into limp mode — so the top-up gets done quickly, before work on a drive off Well Street, or on the way home in the car park outside New Inn. Unfamiliar cars are next, too. Rentals, new vehicles and company motors put their fillers in new places, and habit goes for the cap used on the old one. Nothing stops the pour once it has started, because a bottle with a spout goes into a diesel filler as easily as an AdBlue one. The bottle fits. The same few seconds settle it, in the middle of Tywardreath or out in Par. ## How to tell the AdBlue filler from the diesel one Before you tip anything, whether on a driveway in Kilhallon or a forecourt in Tywardreath, check these. They take a few seconds. - Colour and lettering: an AdBlue cap is commonly blue, or says "AdBlue", where a diesel cap normally doesn't. Trust the cap, not where it sits. - Look at the size: the smaller filler neck is, on many cars, the AdBlue one. - A label inside the fuel flap often shows which fuel goes where, on many cars. Look for it. - Can't find it next to the diesel inlet? Then look beneath the bonnet or in your boot — the owner's manual says where. - Whoever had it before knows. Check as you collect a hire car or fleet car — at Par's car park, say — not once the light comes on. ## Keeping AdBlue out of the diesel tank when you top up A routine for the day the light comes on, wherever in Cornwall that is. - Pull in on level, motor off, with time to spare — not hurried on the side of Fore Street. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds silly and it does the trick. - The two under one flap? So confirm the cap on the diesel side stays closed before lifting the bottle. - Tip slowly, using the bottle's own spout. Stop when it's full or when the bottle is empty. - Close the cap, then check again — making sure your diesel cap remained shut throughout. Only then, start the car. Stop there if you find, at stage two or three, that you've already poured into your diesel side. Leave out stage five altogether. ## Put AdBlue in your diesel tank in Tywardreath already? Don't start the engine: that's where the short order of things begins. Don't switch the ignition on; on many diesels that alone runs the fuel pump. Thinning it with more diesel won't work, since AdBlue settles to the base rather than mixing — and that is where your fuel is pulled from. On a forecourt — Gulf, BP or another — the staff will usually help roll the vehicle clear, if you ask. Your own driveway around Tywardreath is where it should stay. Already started? Stop once it is safe, then turn off. Tywardreath sits over 50 miles from the M5; on it, use the next exit. About how far did it go? Crossing Tywardreath is smaller work than a trip of under 25 miles to Truro, and so say. ## When our engineers arrive around Tywardreath, what happens? Wherever the car has stopped, whether outside Tywardreath School, beside ArtBox or at home, our van comes to it. The replies settle this work and the price, and so our technicians ask what went in, roughly how much, and whether it has run. You get that price by phone, before anyone heads out. 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, and so it doesn't wash out on its own — which is why the flush matters more here than with petrol. Filter flushed or, where it must be, replaced; fresh diesel in; then a check of your car. Before we go, our engineers fire it up and make sure that it is running smoothly. Unrun cars usually need a half-hour job after the moment we arrive. The kit is safe on a busy filling station, and hushed enough for a residential street after dark. Payment is on the day, not upfront, and you receive the documents your insurer wants: an engineer's report and a VAT invoice. Many insurance policies include misfuelling cover, so it is worth checking yours while we are on the way. ## About Tywardreath, briefly Tywardreath is a coastal village in Cornwall, situated near the estuary of the River Par, at an elevation of around 33 metres. Tywardreath has a mix of old and new housing, with detached homes being the predominant type, and is close to the nearby settlements of Par, Polmear, and Treesmill. Tywardreath is located approximately 17 miles from Truro, the nearest city, and about 214 miles from London. ## AdBlue drains in Tywardreath and across Cornwall Tywardreath is a coastal village, and the teams that cover it also work the places near it, Polmear and Treesmill among them, across the PL postcode area. Give a postcode beginning PL24 2, and the van arrives quickest. There's no need to shift the car. Draining takes place on the spot, whether a driveway, a street near Well Street Chapel, or a lay-by on the way to Glencliffe Community Garden. Awkward to explain, like the back of St Andrew's Church, Tywardreath? By a border? Asking is better than assuming, and so phone. ## The short version for Tywardreath motorists Always, the cap; then, the tip. If AdBlue has gone in the diesel tank all the same, leave the vehicle off then ring 0333 366 0103. Petrol in Diesel drains it where it stands, anywhere around Cornwall.