Not every car allows you to refill the AdBlue tank yourself, but you can easily find out if yours does. Behind the fuel filler flap, there’ll be an extra filler with a blue cap for the AdBlue, next to the regular diesel filler. The tank itself is underneath the car, next to the fuel tank.
AdBlue is available from most fuel stations and car parts shops. It comes in containers of up to 10 litres, which typically cost between £15 and £20. The container will come with a nozzle to make pouring the AdBlue into the filler much easier. Alternatively, fuel station HGV lanes have AdBlue pumps that you can use to fill your car if it has a suitable nozzle.
It’s absolutely vital that you don’t accidentally pour AdBlue into your car’s fuel tank. If you do, the tank will need draining and flushing clean. Fortunately, you can’t put diesel in the AdBlue tank by accident because the pump nozzle is far too big.
If your car doesn’t have a dedicated AdBlue filler, the tank can only be refilled by a garage (because the filler is usually hidden below the boot). The tank should be topped up every time your car is serviced, so make sure the garage doing the work includes it. If the tank needs refilling between services, most garages will do so for a small charge.