--- title: Explained: AdBlue in a Diesel Tank Stithians canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/stithians-cornwall/ location: Stithians county: Cornwall latitude: 50.188730 longitude: -5.177840 service: AdBlue in a Diesel Tank updated: 2026-10-07 --- # Avoiding AdBlue in a Diesel Tank in Stithians: Why It Occurs Keep the motor and ignition off then ring 0333 366 0103 now — reading can wait when AdBlue is already in your diesel tank. A drain and a full flush, carried out just where your car stands around Stithians, is usually what it takes when caught before your engine runs. Here before the event? Then what follows covers why it comes about and how to prevent it happening at all. ## AdBlue in a diesel vehicle: two tanks, two fillers Many newer diesels on the roads round Stithians and Tresevern Croft carry two liquids, not one. Diesel goes to your engine. AdBlue goes to the exhaust, where it is sprayed into the gas to fresh it, and it lives in a tank of its own. Different tanks, separate fillers. Plenty of vehicles share a single flap for the two, while others put the AdBlue filler to your boot or under the bonnet. Filling the diesel side at the petrol pump goes on all the time. Someone who has to stop and think where it goes normally fills the AdBlue side, from a bottle, and far less often. That gap is where the error lives. ## How does AdBlue in your diesel tank take place around Stithians? It is seldom carelessness. Three things tend to line up. The warning comes first. As AdBlue runs low your car tells you, and if it runs out completely, the vehicle drops into limp mode. So the top-up is done in a hurry: on a driveway off New Road before work, or in the car park outside Seven Stars Inn on the way home. The old car's cap is where the hand reaches — but a hire car, a new vehicle or a company car keeps the fillers somewhere else. That is a second thing: an unfamiliar car. A spout-topped bottle finds no resistance at a diesel filler no more than at an AdBlue one. So the tip, once started, carries on. It takes seconds, be it out in Hendra or bang in the heart of Stithians. ## The AdBlue filler and the diesel filler: telling them apart Before you pour anything, whether on a driveway in Goonlaze or a forecourt around Stithians, check these. They take a few seconds. - The cap. The AdBlue cap is often blue, or marked "AdBlue". Your diesel cap normally is not. Read it rather than going by position. - The size. On plenty of cars the AdBlue filler neck is the smaller of the two. - The flap. Look inside your fuel flap for a label. Plenty of cars say there which fuel goes where. - The handbook says which it is if the filler is not next to the diesel cap: the boot, or under the bonnet. - Check with the person who drove it last — before you leave, not when the light comes on — if you pick up a hire or company car from somewhere like the car park at Penryn. ## AdBlue top-ups that never reach your diesel tank A routine for the day the light comes on, wherever around Cornwall that is. - Switch off once parked — level ground, motor off, and never in a rush by Crellow Lane on the verge. - Say "AdBlue" out loud as you unscrew the cap, after you find the AdBlue filler and reading it. Silly, 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. - Pour slowly, using the bottle's own spout. Stop when it is full or when the bottle is empty. - Only after that, start the car: close the cap, check again, and make sure your diesel cap was never opened. Discover at the second or third stage that the bottle went in the diesel tank? That is where you stop. Don't go on to stage five. ## Put AdBlue in the diesel tank in Stithians already? The short order of things, beginning with not starting your engine. Don't switch your ignition on; on many diesels that alone runs the fuel pump. Diluting it with extra diesel fails, since AdBlue sinks to the bottom rather than mixing — and that is where the fuel is sucked from. At a forecourt — Gulf, Shell or another — the staff will normally help roll the car away, when you ask. If you're on your own driveway around Stithians, leave the car where it is. When the engine has been run by now, pull over safely and switch it off. Stithians sits over 50 miles from the M5; there, take the next exit. Mileage matters — a short hop across Stithians is a smaller job than driving under 10 miles towards Truro — so tell us about how far it went. ## When our technicians arrive around Stithians, what takes place? Our technicians come to the car wherever it has stopped, whether that's outside Stithians Community Primary School, near The Stithians Centre or on your own drive. Which liquid went in, the quantity, and if it ran: our engineers ask because the answers set both work and quote. You hear that price on the phone, before anybody sets off. Then the tank is drained and the fuel system cleaned thoroughly. Not like petrol, AdBlue leaves crystals and eats at certain fuel-system metals, and neither clears out by itself. Hence it matters more. The filter is cleaned, or replaced where it needs to be; fresh diesel goes in; and your car is tested. The engine is fired up next and checked to be sure it runs properly, all before we head off. Most jobs are done in about half an hour after our technicians arrive, as long as the motor hasn't run — and the pumps our engineers use are safe on a live forecourt yet quiet after dark beside a house. No money upfront; you settle up on the day. At the end, the VAT invoice and a report from the engineer are handed to you for your insurer. Misfuelling cover is part of plenty of insurance policies — so use the wait to check yours. ## About Stithians Stithians is a village situated in a riverside location in Cornwall, with Stithians being close to the nearby city of Truro, approximately 7.6 miles away. Stithians sits at an elevation of around 127 metres, surrounded by rolling countryside and nearby places such as Hendra and Seaureaugh Moor. Stithians has a population of around 1225 people, predominantly living in detached housing. Stithians is located in the South West region of England, about 238.3 miles from London. ## AdBlue drains about Stithians, and Cornwall beyond Tregolls and Seaureaugh Moor are among the places around Stithians, a village, that the same teams cover, throughout TR postcodes. A postcode starting TR3 7 gets the van to you fastest. Your car does not need to move. Wherever it stands — beside St Stythian's Church, on a layby en route to Half Moon Wood, at home — that's where it is drained. Awkward to explain, like the back of United Methodist Free Church? By a border? Asking is better than assuming, and so ring. ## The short version for Stithians motorists Read the cap before you tip. Even so AdBlue in the diesel tank? Petrol in Diesel can drain it where it stands, wherever around Cornwall: switch it off then call 0333 366 0103.