--- title: AdBlue in a Diesel Tank Priory? Leave It Off canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/priory-pembrokeshire/ location: Priory county: Pembrokeshire latitude: 51.724970 longitude: -5.036140 service: AdBlue in a Diesel Tank updated: 2026-10-22 --- # Don't Start It: AdBlue in a Diesel Tank in Priory If AdBlue has gone into your diesel tank, keep your engine off and keep the ignition off. Urea dissolved in water is all AdBlue is. The harm begins once it's pulled through your lines — it will not ignite, and it will not blend with diesel. In Priory, AdBlue in a diesel tank caught before your engine runs usually comes down to a drain and a thorough flush, just where the car is. Nothing comes before calling 0333 366 0103. ## Priory, AdBlue in your diesel tank: what to do at once Do: - Pull the keys out, so no one switches your ignition on. - Hazards on, if moving traffic is anywhere close. - Which fluid, and roughly how much volume? Save the bottle or the receipt, and our engineers can see. - Tell us a postcode starting SA73 3, or whichever street is nearest, and our van reaches you directly — so ring from wherever you stand. Never: - Don't start your engine, even for a moment to shift your car. - Switching the key to ignition by itself sets the pump going on plenty of diesels. Avoid it. - No extra fuel on top. The AdBlue won't mix, so it is pointless. - Leave it where it is instead of driving it anywhere, even a short way up Cromwell Road. - Beside the road, do not try draining it on your own. At a forecourt in Priory, whether it is the Tesco or another one, ask the attendants to help you roll your car away from the pump. On your own drive, do not move it at all. ## AdBlue in a diesel tank: what it does Made for your exhaust, AdBlue has no place in your motor. From a separate reservoir it is fed straight to the exhaust, cleaning what the engine lets out. No part inside a fuel pump is made for this fluid — and no part of it was meant to go through one. Tipped in with the diesel, it keeps apart instead of mixing — quite different from fuel. It's heavier than diesel, and so it sinks and gathers at the bottom of that tank, which is where the pickup draws fuel from. The first thing your fuel system pulls through, once it runs, is the AdBlue. So a car that had AdBlue poured in on a drive in Hubberston last night, and has not been started since, is still the straightforward case: the AdBlue is lying at the bottom of the tank, and nothing has sucked it in. From there it causes two kinds of damage. What is left when the water goes is urea, which forms crystals: they lodge in narrow passages and clog filters. On top of that, it eats at certain metals in the fuel system, and carries on until it's flushed out. Where the AdBlue is in the lines, waiting overnight around Priory makes things worse. Inside the tank alone, waiting costs nothing. The water in it does damage of its own: the high-pressure pump and the injectors depend on diesel to lubricate them, and water gives them nothing. ## Why AdBlue in a diesel is frequently more serious than petrol An issue of thinned fuel is what you get from filling a diesel with petrol at the another forecourt nearby. No harm comes as long as it stays put, blended into the diesel — only when the engine works on it. AdBlue in a diesel is another matter: not thin fuel, but no fuel at all. It cannot simply be run through, since it does not burn. Deposits and corrosion remain through the next fill, and AdBlue splits back out of the diesel, and so thinning it won't work. Hence the flush matters more, and trying the engine "to see" does more harm with AdBlue than almost any other mistake — in Steynton or the heart of Priory alike. With AdBlue, the good news is no distinct from petrol. Never run? Then the AdBlue sits just inside that tank, the easiest bit of the whole system to empty, wherever the vehicle has stopped across Pembrokeshire. ## Priory: how AdBlue ends up in a diesel tank It is not deliberate. Many cars have the AdBlue inlet alongside the diesel one, occasionally under a single flap, and mixing them up is simple after dark. Mostly it's never the forecourt: someone buys a container heading home and tips it in at home. Usually, it occurs in one of a few familiar ways. Midway through the drop-off, the dashboard flags it up, and outside the local primary school the refill is rushed. Near Howarth Close, a driver tips a container in on the drive after work. Or the vehicle is topped up in the car park at Priory Inn, in poor light, by someone who has never opened that flap before. It happens most in the motors drivers know least: a hire car, a new vehicle, a company car, or the second motor of a household with one diesel and one petrol. Wherever in Pembrokeshire, Priory included, the slip doesn't change, and nor does the first response: leave it switched off. ## Started the engine with AdBlue in your diesel tank around Priory? Then the tank is no longer where the AdBlue is. Through the filter, through the lines, and — given any running time — into the high-pressure pump and every injector: that is where it has gone. You may notice the motor running unevenly, smoking, losing power, showing warning lights or cutting out, maybe on the way back from Milford United Football Club or halfway across Priory. When you safely can, stop and switch everything off — with no turning it on again to see. Each start pulls more of that through. Priory sits under 50 miles from the M4; if you were on it, exit by the next junction and stop somewhere safe instead of driving on. How far it went counts. A few hundred yards across Priory to the car park by Milford Haven Leisure Centre is a very different job from a run towards St Davids, under 15 miles away, with the AdBlue reaching further into the system with every mile. Tell us roughly how far it had come. Wherever your car came to a halt is where all of it gets done, even with more to flush after the motor has been started. If it is caught quickly, permanent damage is very rare. ## What draining AdBlue from a diesel involves around Priory Wherever it has stopped around Priory — a filling station, a layby, a drive, a road by Thornton Hall — our van comes to your vehicle. What was put in, roughly the quantity, and if your motor has turned over: our technicians check before all else, since those decide the job. On the spot, your tank is then emptied, and both the polluted diesel and the urea come out as one. What remains from AdBlue will not wash away unaided, and so the fuel system gets a full flush, which matters far more with urea than for petrol. Your filter is flushed, or replaced where it needs to be; fresh diesel goes in; and the vehicle is tested. Not run? In that case count on roughly half an hour on site for most jobs. Low-noise enough for use outside a house at night, and fine on a busy forecourt, our pumps are explosion-proof. New diesel goes in to prime the fuel system, and that's the final step. At that point our engineers start it and you drive off, whether from a parking bay at Milford Haven or a driveway in Priory. Our technicians confirm it runs correctly on new diesel before we go. No garage is required at any point, with the whole job done then and there. The insurer will want an engineer's report and your VAT invoice — each handed over afterwards. ## About Priory itself Priory is a coastal suburban area in Pembrokeshire, situated near the towns of Milford Haven and St Davids. Priory sits at a low elevation of around 20 metres, overlooking the coastline of western Wales. Priory is characterised by its predominantly detached housing stock, reflecting its residential nature. ## Priory and Pembrokeshire: AdBlue drains across the area Thornton, Liddeston and Milford Haven are among the towns around Priory that the same vans serve, together with most of Pembrokeshire beyond, throughout the SA postcode area. Guessing doesn't help by a border or anywhere hard to pin down; ring and ask. Priory is a residential suburb, and a mobile drain suits it: whether the car is on a home drive, a residential street, a car park or a forecourt, our engineers drain it where it is, and so it never needs to be moved to us. ## Priory: what AdBlue in a diesel tank costs to fix There's no fair single quote, since the jobs are not the same. What changes the cost is, first of all, whether the engine has run and for how long; then how much AdBlue got in; and finally where the vehicle is and whether a technician can get to it safely, which is easier on an open driveway than in a tight spot behind Saint Francis Roman Catholic Church. That is why every call from Priory starts with the same three queries, asked before giving a figure, not after: what went in, how much, and whether it has run. The replies turn a range into a straight price. Our price is given on the call, before a van leaves; settling up comes on the day, by card or over the phone, with nothing upfront. Look at your insurance whilst we are on the way: plenty include misfuelling cover. ## Priory: still next to your car? Then, the best thing to do with the vehicle is to not touch it. Keys out; motor and ignition off. Tell us it's AdBlue, about what quantity, and if the engine ran, on 0333 366 0103. From there Petrol in Diesel takes over, across Priory or anywhere within Pembrokeshire.