'12 Evora S delivered with non-functional AC. re-charged system and got it to work, but over 6 months, it gradually lost ability to cool. dealer supposedly found a leak and recharged, but 6 months later, the system will not cool and lacks refrigerant. any tips/tricks on where to look first? my take is, since it was delivered without any refrigerant, the leak is likely to be at a connection point.