--- title: Explained: AdBlue in a Diesel Tank Nether Street canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/nether-street-hertfordshire/ location: Nether Street county: Hertfordshire latitude: 51.825690 longitude: 0.061330 service: AdBlue in a Diesel Tank updated: 2026-10-20 --- # How It Occurs and How to Prevent It: AdBlue in a Diesel Tank in Nether Street Pause reading for a moment when the diesel tank already holds AdBlue in it: ignition off, engine off, then ring 0333 366 0103. Around Nether Street, finding it before the motor turns normally leaves draining and a full flush on the spot. The remainder of this page explains why it takes place and how to ensure it doesn't — useful if you're reading before it has happened. ## AdBlue in a diesel car: two tanks, two fillers Many newer diesels in Kettle Green, as well as Nether Street, carry on two fluids; the engine gets only the diesel. The exhaust, not the engine, is where AdBlue goes: dosed into the fumes to clean it, from a separate tank. Separate tanks, separate fillers. Plenty of vehicles share a single flap for both, while some move the AdBlue filler to the boot or under the bonnet. Filling the diesel side at the pump goes on all the time. Seldom filled, AdBlue usually goes in from a bottle, poured by a driver who has to stop and think which filler to use. The mistake grows in that gap between the two. ## How does AdBlue in your diesel tank occur in Nether Street? Carelessness seldom explains it. What does is three things lining up together. The warning comes first. As AdBlue runs low your car tells you, and if it runs out completely, the car drops into limp mode. So the top-up is done in a hurry: on a driveway off High Street before work, or in the car park outside the pub in the village on the way home. Then, the hand reaches for the cap it knew on the old motor — since a rental car, a new motor or a company car puts the fillers somewhere your last one did not. No part stops the tip after it has started, since a bottle with a spout goes into a diesel filler as easily as an AdBlue one. The bottle fits. The same few seconds decide it, in the middle of Nether Street or out in Widford. ## The AdBlue filler and the diesel filler: telling them apart Be it a Nether Street forecourt or a drive over in Perry Green, take a couple of seconds on these before any is poured in. - Blue and marking: an AdBlue cap is regularly blue, or says "AdBlue", where a diesel cap usually does not. Go by the cap, not where it sits. - Check the size: the smaller neck is, on many vehicles, the AdBlue one. - Open the flap and look for a label — plenty of vehicles mark what goes in which filler just there. - The handbook says which it lives when your filler isn't next to your diesel cap: the boot, or under the bonnet. - The previous driver will know. Check when you pick up a rental or fleet car — from Harlow Town's car park, say — rather than once the light comes on. ## Topping up AdBlue without it reaching the diesel tank A routine for the day the light comes on, wherever around Hertfordshire that is. - Park then switch off. Not on a slope, not with your engine running, and not in a rush on the side of Pegs Lane. - Find the AdBlue filler and read the cap. Say "AdBlue" out loud as you unscrew it. It sounds daft and it works. - Leave the diesel cap on. If both sit under one flap, check the diesel cap is still closed before you lift the bottle. - Using the bottle's own spout, tip slowly — and stop when it's full or the bottle is empty. - Only after that, start the vehicle: close the cap, check again, and make sure your diesel cap was never opened. Find at step two or three that it has already gone into the diesel side? So stop just there. Step five stays out. ## AdBlue in the diesel tank already, in Nether Street? Brief order, then. Top of that: your motor stays off. Keep the ignition off too, since on plenty of diesels it by itself starts your fuel pump. Thinning it with more diesel fails, since AdBlue settles to the base rather than blending — and that is where your fuel is pulled from. If you are on a forecourt, whether it is the Pace or the another forecourt nearby, ask the attendants to help push the vehicle clear of the petrol pump. At home around Nether Street? So your car stays put. Stop as soon as it is safe and switch off, if the motor has already run. Nether Street sits under 10 miles from the M11; on it, take the next exit. Tell us roughly how far it went: a run towards St Albans, under 25 miles away, is a bigger job than a short hop across Nether Street. ## What occurs when we turn up around Nether Street Wherever the vehicle has stopped, be it outside Widford School, beside St John the Baptist or at home, the van travels to it. Both the work and the price depend on three answers — which liquid, what quantity, and if it has run — so our technicians ask. The quote is given over the phone, before any van leaves. Draining that tank comes next, then a thorough flush of the fuel system. Unlike petrol, AdBlue forms crystals and attacks some fuel-system metals, and none of that washes out unaided. Hence it counts more. Once your filter has been cleaned — or renewed, if required — clean diesel goes in, and then your car gets tested. Next our technicians fire it up and make sure it runs properly before we leave. Most jobs are finished in roughly half an hour after we get there, as long as your motor has not run — and the pumps we use are fine on a busy forecourt and quiet after dark beside a house. Nothing upfront; you settle up on the day. At the end, a VAT invoice and the report from the engineer go to you for your insurer. It is worth looking at your policy as the van travels to you: misfuelling cover comes with many policies. ## About Nether Street, briefly Nether Street is a small hamlet in Hertfordshire, situated on the riverside at an elevation of 72 metres. Nether Street lies near the villages of Widford and Hunsdon, and is within commuting distance of St Albans and London. Nether Street is characterized by its predominantly detached housing stock, reflecting its rural setting. Nether Street remains a quiet residential community with a population of around 658 people. ## AdBlue drains about Nether Street, and Hertfordshire beyond Being a rural hamlet, Nether Street shares its vans surrounding areas — South-end, Hunsdon — right across SG postcodes and the wider area around them. A postcode starting SG12 8 gets our van to you fastest. Shifting your car isn't needed. Anywhere it stands — beside Large Upright Internal/External Form, in a lay-by en route to Lilley's Wood, at home — that's where it gets drained. If you are close to a border, or somewhere hard to describe like the back of Turtle, ring and ask rather than assuming. ## For Nether Street drivers, the short version Read the cap before you tip. If AdBlue has gone in the diesel tank all the same, leave the car off and ring 0333 366 0103. Petrol in Diesel clears it where it waits, anywhere around Hertfordshire.