Allithwaite: How Does AdBlue End Up in a Diesel Tank, and How Do You Prevent It?

Two fillers, two tanks: AdBlue in a diesel motor

Many newer diesels on the roads about Allithwaite and Flookburgh carry two liquids, not one. Diesel goes to the engine. Kept in a tank of its own, AdBlue is sprayed into the exhaust stream and cleans it.

Different tanks, different fillers. Under one flap, next to each other: that is the layout on a lot of vehicles. On others, AdBlue's filler sits beneath the bonnet or in the boot instead. Topping up your diesel side at the petrol pump goes on constantly. The AdBlue side is topped up far less often, usually from a bottle, and usually by someone who has to stop and think where it goes. That gap is where the slip lives.

Which filler is for AdBlue, and which for diesel?

A couple of seconds is all the checks take — so check them before you pour anything, on a drive in Grange-over-Sands or a forecourt around Allithwaite.

• Where it sits can mislead; the cap does not. AdBlue ones tend to be blue or bear the word "AdBlue" — diesel ones usually don't.
• On plenty of motors, size gives it away: AdBlue gets the smaller filler neck.
• A label inside your fuel flap frequently shows which fuel goes where, on plenty of cars. Check for it.
• The handbook. If the filler is not by the diesel cap, it's in your boot or under the bonnet, and the handbook says which.
• Check with the person who drove it last — before you leave, not when the light comes on — when you collect a hire or company car from somewhere like the car park at Kents Bank.

Allithwaite: what happens when our engineers turn up

Wherever the vehicle has stopped, be it by Allithwaite CofE Primary School, beside Allithwaite Community Centre or at home, our van travels to it. Those answers determine this work and the quote, and so our engineers ask what was put in, roughly how much, and if it has run. No one sets off until you have had our quote by phone.

Emptying the tank comes next, then a full flush of your system. Much more than with petrol, it matters with AdBlue: crystals form, some metals corrode, and none of it washes away on its own, however long it sits. A test is at the end: before that, fresh diesel goes in, and the filter is flushed or replaced if necessary. We don't go until it has been started and is running smoothly.

Unstarted cars mostly need a half-hour job after arrival. The kit is fine on a live filling station, and quiet enough for a driveway after dark. Payment happens on the day, not upfront, and you receive the documents an insurer wants: an engineer's report and a VAT invoice. Misfuelling cover is part of many insurance policies — and so make use of the wait to check yours.