How It Occurs and How to Prevent It: AdBlue in a Diesel Tank in Markham

Why does AdBlue in a diesel vehicle need its own filler?

No single fluid but two: that's how plenty of modern diesels around Markham and Aberbargoed carry, with diesel for your engine. Kept in a tank of its own, AdBlue is sprayed into the exhaust stream to clean it.

Each tank has its own filler. Many of cars have a single flap for the two, while some put the AdBlue filler to the boot or under the bonnet. The diesel side is filled at the petrol pump all the time. Seldom filled, AdBlue usually goes in from a bottle, tipped by someone who has to stop and think what cap it needs. That gap is where the mistake lives.

How to tell the AdBlue filler from the diesel one

Look at these first, at a forecourt in Markham or a drive over in Cwm-corrwg. Seconds, that's all.

• Colour and lettering: an AdBlue cap is commonly blue, or says "AdBlue", where a diesel cap usually does not. Trust the cap, not its position.
• Look at the size: the smaller filler neck is, on many cars, the AdBlue one.
• Open the flap and check for a label — plenty of cars mark which goes in each inlet just there.
• Cannot see it beside the diesel filler? In that case check beneath the bonnet or in the boot — the handbook will say where.
• Ask the person who drove it last — before you leave, not when the light comes on — when you pick up a hire or company car from somewhere like the car park outside Brithdir.

Markham: what happens when we arrive

Anywhere the vehicle has stopped, whether by the local primary school, beside Markham Miners institute or at home, our van travels to it. What liquid got in, the amount, and whether it ran: we ask since the answers decide the work and price. That quote comes on the call, before any van leaves.

Next: draining, then a thorough flush of the whole system. AdBlue crystallises and is corrosive to some of the metals in a fuel system, so it does not wash out on its own — which is why the flush matters more with AdBlue than with petrol. Your filter is cleaned, or replaced where it needs to be; clean diesel goes in; and the car is tested. Before leaving, our technicians fire it up and check that it is running smoothly.

Most jobs are finished in roughly half an hour once our engineers arrive, as long as your motor hasn't run — and the pumps our technicians use are safe on a busy forecourt yet quiet at night beside a house. The insurer usually wants an engineer's report and your VAT invoice, and both are yours at the end. Payment comes on the day, with no money upfront. Misfuelling cover is part of many insurance policies — and so use the wait to look at yours.