--- title: AdBlue in a Diesel Tank Trevellas? Read This canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/trevellas-cornwall/ location: Trevellas county: Cornwall latitude: 50.321000 longitude: -5.176130 service: AdBlue in a Diesel Tank updated: 2026-10-24 --- # Trevellas: How Does AdBlue End Up in a Diesel Tank, and How Do You Avoid It? If AdBlue is already in your diesel tank, stop reading for a moment: leave your motor and the ignition off then ring 0333 366 0103. A drain plus a thorough flush, done just where your car stands around Trevellas, is normally all it needs if found before your motor runs. Here in advance? In that case the rest covers how it happens and how to prevent it ever happening. ## Two fillers, two tanks: AdBlue in a diesel motor Many current diesels on the roads around Trevellas and Wheal Kitty carry two liquids, not one. Diesel goes to the engine. AdBlue goes to the exhaust, where it is sprayed into the gas to clean it, and it lives in a tank of its own. Every tank has one filler of its own. Under one flap, side by side: that's the layout on a lot of cars. On others, AdBlue's filler sits under the bonnet or in the boot instead. Diesel goes in on each filling station visit, week in, week out. The AdBlue side is filled far less frequently, usually from a bottle, and usually by a person who has to stop and think where it goes. That gap is where the slip lives. ## Trevellas: how AdBlue in your diesel tank takes place It's seldom carelessness. Three things tend to line up. Haste comes from the warning. The car warns you as AdBlue runs low, and an empty tank puts the vehicle into limp mode — so the top-up happens in a rush, before work on a driveway off B3285, or on the way home in the car park at Miners Arms. Unfamiliar vehicles are next, too. Hire cars, new vehicles and company cars put their fillers in new places, and habit reaches for the cap it 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, so nothing stops the tip after it has started. The same few seconds settle it, in the middle of Trevellas or out in Mithian. ## The AdBlue filler and the diesel filler: telling them apart Before you pour anything, whether on a drive in Cross Coombe or a forecourt in Trevellas, check these. They take a couple of seconds. - Check the cap rather than going by position: AdBlue ones are regularly blue or marked "AdBlue", and diesel ones usually aren't. - The size. On many cars the AdBlue filler neck is the smaller of the two. - The flap. Look inside the fuel flap for a label. Many cars say there which fuel goes where. - The handbook. If the filler is not by your diesel cap, it's in your boot or under the bonnet, and the handbook says which. - Collecting a hire or company car, perhaps at the car park at Truro? Check with the person who drove the car last before you set off, not once the light comes on. ## Keeping AdBlue out of the diesel tank when you top up For the day the warning comes on — anywhere you are in Cornwall — a routine to follow. - Not in a rush on the side of Wheal Kitty Lane, not on a slope, not with the motor running: park then switch off properly. - Locate the AdBlue filler, check the cap, and speak the word "AdBlue" aloud as unscrewing it. It sounds daft. It works. - If both sit under one flap, check your diesel cap is still closed before you lift the bottle — and leave it on. - Slowly does it, through the bottle's own spout, till it is full or the bottle runs out. - Only then, start the car: close the cap, check again, and make sure the diesel cap was never opened. Spot at stage two or three that it's already gone into the diesel side? So stop right there. Do not go on to stage five. ## Trevellas: already put AdBlue in the diesel tank? Then the order of things is short. Do not start the engine. The fuel pump starts on many diesels the moment your ignition is switched on — so keep it off. Topping up with diesel won't thin it: instead, AdBlue drops to the bottom of the tank, right where fuel is drawn from. If you're at a forecourt, whether it is the the nearest petrol station or the Texaco, ask the attendants to help push the vehicle clear of the petrol pump. Your own driveway around Trevellas is where it stays. If your engine has already run, stop as soon as it is safe then switch off. The next junction is where to leave when you're on the M5, over 50 miles from Trevellas. About how far did it go? Hopping across Trevellas is less work than a run of under 10 miles to Truro, so tell us. ## Trevellas: what happens when we turn up Wherever the car has stopped, be it by Mithian School, beside Mithian Village Hall or at home, the van comes to it. Which liquid got in, the quantity, and if it ran: our technicians ask because the answers decide both work and price. The price is given on the call, ahead of any van leaving. Your system is then purged thoroughly, after that tank is drained. Unlike petrol, AdBlue forms crystals and attacks certain fuel-system metals, and neither washes away unaided. That is why it counts more. The fuel filter is cleaned, or replaced where it needs to be; fresh diesel goes in; and the vehicle is tested. Before we go, our engineers fire it up and confirm that it's running properly. With pumps safe on a working forecourt and quiet enough to use outside a house at night, most jobs where your motor hasn't run take roughly half an hour once we arrive. The insurer will ask for an engineer's report and your VAT invoice, and you get both once this job is done. Payment is on the day, with no deposit. It is worth looking at your policy as the van travels to you: misfuelling cover comes with plenty of policies. ## About Trevellas and where it is Trevellas is a small coastal village in Cornwall, situated near the town of Truro and overlooking the Atlantic coast. Trevellas has a population of around 505 people and is characterised by its predominantly detached housing stock. Trevellas sits at an elevation of approximately 100 metres, with nearby villages including Mithian and Perrancoombe. Trevellas is located about 6.8 miles from Truro, the nearest city. ## AdBlue drains around Trevellas, and Cornwall beyond Barkla Shop and Perrancoombe are among the places near Trevellas, a coastal village, that the same vans cover, over TR postcodes. Fastest of all: give a TR5 0 postcode for the van. The vehicle stays put. Draining happens on the spot, whether a drive, a road by Blue Hills Tin Streams, or a layby on the way to Goonown Playing Field. Ring and ask instead of guessing if you're close to a boundary, or somewhere hard to describe, like the back of St Agnes. ## In short, for Trevellas drivers Read the cap before you tip. Petrol in Diesel drains it where it stands, anywhere in Cornwall, if AdBlue has gone in the diesel tank all the same — so leave the vehicle off then ring 0333 366 0103.