--- title: Don't Start It: AdBlue in a Diesel Tank Cwmfelin canonical: https://www.petrolinadieselcar.co.uk/adblue-in-diesel/cwmfelin-bridgend/ location: Cwmfelin county: Bridgend latitude: 51.594030 longitude: -3.639370 service: AdBlue in a Diesel Tank updated: 2026-10-24 --- # Cwmfelin: AdBlue in the Diesel Tank? Leave It Off With AdBlue in your diesel tank, your ignition remains off and so does the motor. Urea dissolved in water is what AdBlue is. Unlike fuel, it neither ignites nor blends, and nothing starts till the engine sucks it round. In Cwmfelin, AdBlue in a diesel tank found before the engine runs usually means a drain and a thorough flush, just where the vehicle is. Before anything, phone us on 0333 366 0103. ## Cwmfelin, AdBlue in the diesel tank: what to do straight away To do: - Take the keys out, and so nobody switches your ignition on. - If you are at all close to moving traffic, put your hazards on. - The empty bottle or the receipt tells us the fluid and the amount, and so don't bin it out. - Ring just where you are. Quote a CF34 9 postcode or the closest street sign, and nobody has to hunt for you. Things not to do: - Shifting your car even a short way is no reason to start your engine. - The ignition remains off: on many diesels, turning it on is enough to start your fuel pump. - Adding more diesel doesn't help: AdBlue separates out instead of thinning. - Even a short distance along Gartholwg is too far to drive it. - Do not try to drain the vehicle yourself at the roadside. Rolling the car away from the pumps is a job for staff to help with, whichever Cwmfelin forecourt you are on, the the nearest petrol station included. If you're on your own drive, leave it just where it stands. ## What AdBlue does in a diesel tank The motor is not what AdBlue is made for; your exhaust is. Stored in a separate tank, it is injected into the exhaust to treat the gases. Nothing inside a fuel pump is designed for this fluid — and none of that was meant to travel that way. Fuel mixes; AdBlue, once poured in, will not. Its behaviour is nothing like diesel's. It sinks, because it's heavier than diesel, and pools down where the pickup takes its fuel from. Simplest of all: a vehicle that had AdBlue in Llwydarth overnight and has not been started since. The AdBlue sits at the base of your tank, undrawn — though it will be first through if the motor starts, ahead of any diesel at all. From there it causes two kinds of damage. What is left once the water evaporates is urea, which turns into crystals: they lodge in tiny channels and block filters. Worse, it eats at some metals in the fuel system, and carries on till it is cleared out. A vehicle left standing around Cwmfelin with AdBlue already in its lines is worse by the morning; one with AdBlue just in its tank isn't. The water in it does harm of its own: the high-pressure fuel pump and your injectors rely on diesel to lubricate them, and water offers them nothing. ## Why is AdBlue in a diesel regularly the bigger fault? A problem of thinned fuel is what you end up with from fuelling a diesel with petrol at the Oils for Wales. Blended through your diesel and sitting unused, it is no threat for now; running your engine is the damage. With AdBlue in a diesel, the fluid itself is simply the wrong one. Since it doesn't burn, running it through isn't an option. Nor can it be watered down, because it splits again — and the next fill won't clear away crystals or corrosion. So the flush counts more here, and turning your key "to see", in the heart of Cwmfelin or out in Y Parc, does more harm than nearly any other slip. The same good news applies as with petrol. Clearing a tank is the simplest part on a fuel system, and without start-up, the AdBlue stays in it — anywhere across Bridgend the car has stopped. ## How does AdBlue end up in a diesel tank around Cwmfelin? After dark, two caps side by side — the AdBlue one and the diesel one, now and then under a single flap — may appear the same. Nobody intends it; many designs invite it. Most of the time it takes place with a bottle bought on the way home and poured in on the driveway, not at the forecourt. A couple of familiar ways account for the majority of them. Midway through the drop-off, the dashboard warns, and outside the local primary school the refill is rushed. A bottle is poured in at the end of the day on a drive just off Cwrt Y Fedwen. Or the car is topped up in the car park outside The Garth Inn, in poor light, by somebody who has never opened that flap before. It crops up the most in a hire car, a brand-new vehicle, a fleet car, or the spare motor of a home with one of each fuels — the cars people know the least. Wherever you are in Cwmfelin or the remainder of Bridgend, it's the same slip and the same first answer: leave the vehicle off. ## AdBlue in your diesel tank in Cwmfelin, and your engine started? Then your tank is no longer where the AdBlue is. The fuel filter and lines have had it sucked along, and any running takes it on to the injection pump and each injector. Maybe coming back from Parc Tir Iarll, or part way across Cwmfelin, the engine might go rough, smoke, lose pace, flash the dash or cut out. When you safely can, pull over and turn everything off — with no restarting to see. Each start pulls more of it through. If you were on the M4, under 5 miles from Cwmfelin, come off at the next junction and stop somewhere sensible instead of pressing on. A quick hop across Cwmfelin to the car park by Llangynwyd Rangers BGFC is one matter; heading towards Swansea, under 15 miles away, is another, because each mile carries the AdBlue deeper in. So mileage matters. Approximately how far had it come? Tell us. Our technicians do all of the flushing where the vehicle has ended up, and once the motor has been run there is more of it. Long-term damage is very unusual when it is noticed quickly. ## What does an AdBlue drain on a diesel involve around Cwmfelin? Our engineers come to your car, wherever it has stopped in Cwmfelin: a side street near Shilo Church, a drive, a lay-by or a forecourt. Three answers decide the job, so first our technicians ask what went in, about the amount, and whether your engine has turned over. Then the tank is cleared where your car stands, and so the polluted fuel and the AdBlue come out together. With AdBlue, far more than with petrol, the flush counts: the whole system is flushed right through since residue will not wash away unaided. The filter is flushed, or replaced where it needs to be; clean diesel goes in; and the vehicle is tested. Most of these jobs are a half-hour visit once we arrive, provided the engine has not run. Explosion-proof pumps mean a busy forecourt sensible to work on, and they're quiet enough to spare the neighbours at night. The last step is to prime the system on new diesel. You drive off as soon as our technicians have started the engine, and it makes no difference whether the vehicle is on a drive in Cwmfelin or in a space by Garth (Mid Glamorgan). Our technicians check it runs properly on new diesel before we leave. Because the job is done in full where the car is, a workshop never comes into it. At the end, you are given the paperwork for the insurer: a VAT invoice plus a written report from the engineer. ## About Cwmfelin, for a moment Cwmfelin is a suburban area in Bridgend, situated on the riverside at an elevation of 98 metres. Cwmfelin lies near the communities of Garth, Pont Rhyd-y-cyff, and Llangynwyd, and is approximately 13 miles from Swansea. Cwmfelin has a population of around 2738 people, predominantly living in detached housing. Cwmfelin is also within commuting distance of major cities, being around 151 miles from London. ## AdBlue drains across Cwmfelin and Bridgend Throughout the CF postcode area, the vans taking AdBlue call-outs around Cwmfelin reach most of Bridgend too, Garth, Pont Rhyd-y-cyff and Llangynwyd included. Close to a boundary, or somewhere tricky to explain? Asking is better than guessing, and so phone. Wherever your vehicle sits — your drive at home, a side street, a parking area, a forecourt — we drain it there, and there's no need to take it to us; which suits Cwmfelin, a residential suburb, well. ## What does AdBlue in a diesel tank cost to sort out around Cwmfelin? No single figure could be fair, since every job differs. The price shifts first with how long, if at all, the engine has been running, and next with the amount of AdBlue that got in. After that it depends on where the vehicle is and whether our van can get to it safely, which is simpler on an open driveway than in a tight spot behind House Platform. That is why each call from Cwmfelin starts with the same three queries, asked before giving a figure, not after: what was put in, how much, and whether it has run. When they are known, a range turns into one fixed number. You get that quote on the phone, before anyone heads out, and you pay on the day, by card or over the phone, with nothing upfront. As the van is on the way, dig out your policy: many include misfuelling. ## Cwmfelin: still next to the vehicle? Not touching your car is, right now, the best thing you can do. Engine off, keys out, ignition off. Petrol in Diesel handles the remainder, in Cwmfelin or wherever in Bridgend, after you call 0333 366 0103 to say it was AdBlue, roughly how big an amount, and if the engine ran.