As a Euro6 compliant vehicle, the Audi A6 Avant is the first car we’ve had as a long-termer that requires AdBlue.

What does this mean? Possible not much for Fleet News, as our cars generally return to the manufacturer after six months with between 6,000-8,000 miles on the clock. For a fleet, it means rather more.

Audi says that the 17-litre AdBlue tank will need refilling on average every 10,000 miles, depending on driving behaviour, engine temperature, vehicle loads and towing (although the owner’s manual recommends a top-up is included with the 20,000-mile service).

Fleets have two choices: purchase AdBlue in 1,890ml bottles with a filler neck valve at £5.50 excluding VAT. Audi recommends filling with 5.7 litres of AdBlue, equating to three bottles, at a cost of £16.50.

Alternatively, Audi dealers sell five litre bottles costing £5.69+VAT but they do not come with a filler neck valve. Contents have to be loaded into a filling device at a labour charge of 12 minutes if part of a service or 18 minutes if it’s a standalone job. The actual cost will vary by region, advises Audi.

At an hourly labour charge of £60, for instance, this means another £5 if part of a service. The total cost via a dealership of just over £10 will be carried out potentially eight times over an 80,000 operating cycle - £80 to add to the SMR costs.

Not much, perhaps, but any additional cost is unwelcomed.

Fail to fill the tank and the car will go into limp-home mode. No long-term damage will be done, but it’s obviously ill-advised to ignore the dashboard light when it illuminates.

Audi says it is working on a fixed price offer for AdBlue, suggesting the price will reduce as Euro6 vehicles become more commonplace. Plus, every manufacturer choosing the AdBlue route to compliance will be in the same position. Costed out, this could add up to £8,000 for a fleet of 100 over a full lifecycle.

Meanwhile, the A6 remains a charming companion offering superb road manners, a comfortable drive and reasonable efficiency. We’re still stuck in the low to mid 50s for fuel consumption but that’s more down to driving style as anything.

Stephen Briers