--- title: Lower Boscaswell: AdBlue in a Diesel Tank, Explained canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/lower-boscaswell-cornwall/ location: Lower Boscaswell county: Cornwall latitude: 50.154120 longitude: -5.669710 service: AdBlue in a Diesel Tank updated: 2026-10-24 --- # Avoiding AdBlue in a Diesel Tank in Lower Boscaswell: Why It Occurs Pause reading for a moment when the diesel tank already has AdBlue in it: ignition off, engine off, then call 0333 366 0103. Around Lower Boscaswell, catching it before the motor turns usually leaves draining and a thorough flush on the spot. Here in advance? Then the rest covers how it comes about and what to prevent it ever happening. ## AdBlue in a diesel vehicle, and its separate tank No single liquid but two: that's how many newer diesels around Lower Boscaswell and Lower Trewellard carry, with diesel feeding your motor. Kept in a tank of its own, AdBlue is sprayed into your exhaust gas to clean it. Each tank has its own filler. On a lot of cars the two sit side by side under the same flap; on others the AdBlue filler is in your boot or under the bonnet. Diesel gets filled on every filling station call-out, week in, week out. Far less regularly, the AdBlue side is topped up — mostly from a bottle, by someone working out where it goes. The error lives in that gap. ## How does AdBlue in your diesel tank occur around Lower Boscaswell? Three things tend to line up, and carelessness is rarely one of them. On a drive off Moorland Close before work, or in the car park outside The North Inn on the way home: that's where the hurried top-up happens. What is the reason for the rush? As AdBlue gets low the car warns you, and if it's gone, limp mode follows. New-to-you cars are next, as well. Rentals, new cars and company cars place their fillers in new places, and habit goes for the cap it used on the old one. A spout-topped bottle meets no obstacle at a diesel filler no more than at an AdBlue one. So the pour, after started, keeps on. Whether it occurs in Higher Boscaswell or the middle of Lower Boscaswell, it is the same few seconds. ## The AdBlue filler and your diesel filler: telling them apart Look at these before pouring, at a forecourt in Lower Boscaswell or a driveway over in Trewellard. A few seconds, no more. - The cap. The AdBlue cap is regularly blue, or marked "AdBlue". Your diesel cap usually is not. Read it instead of going by position. - Many vehicles give AdBlue the smaller neck of the two. - Lift the filler flap and check for a label — plenty of vehicles show what goes in each inlet right there. - In your boot or under the bonnet: that's where the filler is if it's not by the diesel cap, and the handbook says which. - The person who drove the vehicle last. On a hire or company car picked up from somewhere like the car park at Penzance, ask before you leave, not when the light comes on. ## Keeping AdBlue out of the diesel tank when you top up Wherever across Cornwall the light comes on, here is a routine for that day. - Park and switch off. Not on a slope, not with the engine running, and not in a rush on the side of Croft Mear. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds daft and it does the trick. - The diesel cap stays on. When the two sit under a flap, make sure it's closed before the bottle comes up. - Stop when your tank fills or the bottle runs dry; until then, tip gently using the built-in spout. - Before you start your car, shut the cap and check again that your diesel cap was never came off. Spot at stage two or three that it's already gone into your diesel side? So stop right there. Never go on to stage five. ## AdBlue in your diesel tank already, around Lower Boscaswell? The short order of things, beginning with not starting the engine. Do not switch the ignition on; on many diesels that alone runs the fuel pump. Topping up with diesel won't thin it: rather than mixing, AdBlue sinks to the bottom of your tank, right where fuel is taken from. Ask the attendants to help roll the vehicle away from the pump if you're on a forecourt — the Trewellard Garage, the another forecourt nearby or anywhere else. If you're on your own driveway in Lower Boscaswell, leave it where it sits. Where the engine has run already, stop safely then turn it off. The next junction is where to leave when you are on the M5, over 50 miles from Lower Boscaswell. A short hop across Lower Boscaswell is a smaller job than a run towards Truro, under 50 miles away, so tell us about how far it went. ## What occurs when we turn up around Lower Boscaswell By Pendeen School, close to Hard Rock Museum or on your own drive: wherever your car has stopped, our technicians come to it. Both the work and the price rest on three answers — which liquid, what amount, and if it's run — so our technicians ask. You get that price on the phone, before anybody sets off. The fuel system is then flushed thoroughly, once your tank is drained. 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 that matters more with AdBlue than with petrol. Filter flushed or, if it must be, swapped; fresh diesel in; then a check of your vehicle. Next our technicians fire it up and confirm it runs correctly before leaving. If your engine hasn't run, most jobs take about half an hour once we're there, using pumps that are safe on a working forecourt and quiet enough to use outside a house at night. Nothing in advance; you settle up that day. Afterwards, a VAT invoice and a report from the engineer are handed to you for the insurer. Wrong-fuel cover is part of plenty of insurance policies — and so make use of the wait to check yours. ## About Lower Boscaswell and where it is Lower Boscaswell is a small suburban area in Cornwall, situated on the coast at an elevation of 113 metres, with views out to the Atlantic Ocean. Lower Boscaswell has a mix of housing types, but terraced homes are particularly prevalent, reflecting the area's history of development. Lower Boscaswell is located near several other small settlements, including Higher Boscaswell and Pendeen, and is within commuting distance of Truro. Lower Boscaswell remains a relatively small community, with a population of around 691 people. ## AdBlue drains across Cornwall, Lower Boscaswell included Pendeen and Portherras are among the towns near Lower Boscaswell, a residential suburb, that the same vans cover, throughout TR postcodes. Give a postcode beginning TR19 7, and our van arrives quickest. There's no need to shift the vehicle. The drain takes place right there, whether a driveway, a street by Pendeen Parish Hall and Theatre, or a layby on the way to Silver Jubilee Park. Assuming doesn't help behind Geevor Tin Mine, on a border, or anywhere awkward to describe; phone and ask. ## Lower Boscaswell motorists: the short version Tip no AdBlue till you've read the cap. Petrol in Diesel drains it on the spot, anywhere in Cornwall, if AdBlue has gone in your diesel tank regardless — and so leave the vehicle off and call 0333 366 0103.