Had this same air con nightmare on my 2003 galaxy 2.3 Zetec, upon inspection found loads of crud under drier cap this was after 2 regases. Working for nissan and having an idea how cars are madeI decided to remove circlip and drier cap, this can be done by putting an old screw into the opening and gently levering out, this can all be done by removing 4 spline screws and small grill with ford badge on, please note this can be difficult as it is vaccum tight (drier cap). I could see where the seals had failed, a new drier car was bought from europarts for