Tredomen: How Does AdBlue End Up in a Diesel Tank, and How Do You Avoid It?
Leave your engine and ignition off then ring 0333 366 0103 now — the rest can wait when AdBlue is already in your diesel tank. Around Tredomen, catching it before your engine turns usually means a drain and a thorough flush where it stands. If you're reading before it has happened, the rest of this page is about why it happens and how to make sure it does not.
AdBlue in a diesel vehicle: two tanks, two fillers
Diesel feeds your motor — but plenty of modern diesels seen about Tredomen and Maesycwmmer hold another liquid too. AdBlue's own tank holds it, and from there it is sent to your exhaust, where spraying treats the gas.
Separate tanks, separate fillers. Other vehicles put the AdBlue filler in the boot or under the bonnet; a lot of others have both side by side under one flap. At the pump, your diesel side gets filled constantly. Far less often, the AdBlue side is filled — mostly from a bottle, by a person working out where it goes. That gap is where the slip lives.
AdBlue in the diesel tank in Tredomen: how it happens
Rarely is it carelessness: normally three things coincide.
The warning comes first. As AdBlue runs low your car tells you, and if it runs out completely, the vehicle goes into limp mode. So the top-up is done in a hurry: on a driveway off Tyn-y-Coed before work, or in the car park at Ystrad Mynach Non Political Club on the way home.
The old car's filler is where the hand goes — but a rental car, a new motor or a company car keeps the fillers elsewhere. That is the second thing: an unfamiliar motor.
Third, the bottle goes in: diesel filler or AdBlue one, it slides in as readily, and once the tip starts, nothing stops it. Whether it takes place in Ystrad Mynach or the middle of Tredomen, it's the same few seconds.
How to tell the AdBlue filler from the diesel one
Whether a Tredomen forecourt or a drive out in Cefn Hengoed, spend a few seconds over these before anything goes in.
- Position misleads; the cap does not. AdBlue caps tend to be blue or carry the word "AdBlue" — diesel ones normally do not.
- The size. On plenty of motors the AdBlue filler neck is the smaller of the two.
- Check inside your fuel flap: many cars carry a label there showing which fuel goes where.
- The handbook shows which it is if the filler is not next to the diesel cap: your boot, or under the bonnet.
- The person who drove the vehicle last. On a hire or company car picked up from somewhere like the car park at Ystrad Mynach, ask before you leave, not when the light comes on.
How to top up without AdBlue in your diesel tank
When the light comes on, anywhere across Caerphilly, follow this routine.
- Park then switch off. Not on a slope, not with your motor running, and not in a rush on the side of Brynmynach Avenue.
- Find the AdBlue filler, check the cap, and say the word "AdBlue" out loud while unscrewing it. It seems daft. It does the trick.
- If both sit under one flap, check your diesel cap is still closed before you lift the bottle — then leave the car on.
- Stop when the tank is topped up or the bottle is empty; before that, tip gently using its built-in spout.
- Close the cap and check again. Make sure your diesel cap was never opened. Only then start the vehicle.
Stop there if you find, at stage two or three, that you have already poured into the diesel side. Stage five stays off limits.
Put AdBlue in your diesel tank around Tredomen already?
What follows is a short order of things, starting with no starting the engine. Leave your ignition off too, because on plenty of diesels it by itself starts the fuel pump. AdBlue doesn't mix with diesel — it sinks to the bottom of the tank, where your fuel is drawn from — so don't top up with diesel to dilute it.
The attendants at Petrol, Texaco or any forecourt will usually help to push the vehicle clear if asked. If you are on your own driveway around Tredomen, leave the vehicle where it stands.
Already run? Stop once it's safe, then switch off. On the M4, under 10 miles from Tredomen, that means the next exit. A short hop across Tredomen is a smaller job than a run towards Newport, under 15 miles away, and so tell us about how far it went.
Our arrival in Tredomen, and what happens next
Outside the local primary school, close to Holy Trinity or on your own drive: wherever the car has stopped, our engineers come to it. Both the work and the quote rest on three replies — which liquid, which amount, and if it has run — so we ask. You hear that quote by phone, before anybody heads out.
Then that tank is drained and the system flushed thoroughly. With AdBlue that matters more than with petrol: it crystallises and is corrosive to some of the metals in a fuel system, so it does not wash out on its own. The filter cleaned or, where needed, swapped; fresh diesel in; then a check of your vehicle. Then our engineers fire it up and make sure it runs smoothly before we go.
If your engine hasn't run, the majority of jobs take about half an hour once we're there, using pumps that are safe on a busy forecourt and quiet enough to use outside a house after dark. You pay on the day, with nothing upfront, and get a VAT invoice and an engineer report for your insurer. Misfuelling cover is part of many insurance policies — and so make use of the wait to check yours.
About Tredomen, for a moment
Tredomen is a suburban area in Caerphilly, situated near the banks of a river at an elevation of around 135 metres. Tredomen lies approximately 11 miles north of Newport and is close to nearby places such as Ystrad Mynach and Hengoed. Tredomen is characterized by its predominantly semi-detached housing stock and is home to a population of around 2714 people. Tredomen is also near Parc Penallta Country Park, a local area of natural beauty.
AdBlue drains in Tredomen and across Caerphilly
Tredomen is a residential suburb, and our vans that cover it also work the towns around it, Hengoed and Parc Penallta Country Park among them, across the CF postcode area. A postcode starting CF82 7 gets the van to you fastest.
Moving the car is not needed. A driveway, a lay-by on the way to Ystrad Mynach Park, a side street near Ystrad Mynach Library: our technicians drain the car where it stands. Guessing won't help at the back of Sue Noake Leisure Centre, on a border, or anywhere hard to pin down; ring and ask.
The short version for Tredomen motorists
Pour no AdBlue until you've read the cap. Even so AdBlue in your diesel tank? Petrol in Diesel can drain it wherever it stands, wherever in Caerphilly: switch the car off then ring 0333 366 0103.