LBR

Assuming the system has a leak, the most overlooked leak is the evaporator. Its a little hard to, but it can be done. Remove passenger knee bolster and glove box. Cover to evaporator is combined with vacuum tank. A handful of screws arond the perimiter and carefully pry (the seam is filled with body putty, so pry slowly and gently) and you can see the back end and down the sides of the evaporator. We always add A/C leak dye to our systems when we recharge, so it should be apparent if there is a leak. Because of the age of these cars, the guys pretty much check them when we get a car in wwith low refrigerant.

FSB