Swapped cars with my girlfriend yesterday as she had a work event in Essex, so she had my Volvo T5 for the day. Amazingly she managed 41.8mpg, which is higher than I've ever seen from a 5 pot turbo! Even more impressive......she noticed a smell coming through the air vents on the way home. She described it as a 'sweet curry' smell - Can only be coolant Stripped apart a load of the dash last night after it had cooled off, assumed the heater matrix was leaking, no puddles on the carpet though. Turns out one of the O rings is weeping, which is a relief as the heater matrix requires nearly the entire dash to come out, around 5 hours of labour at Volvo. Coolant flush + few O rings and clamps and it'll be sorted. Not the easiest of jobs though - One for the long weekend.