What was found
ACFT MILES FROM DESTINATION WHEN CREW NOTICED CABIN TEMP WAS HIGH. CABIN CONTROL WAS ON 'AUTO MODE'. CHANGING TO 'MANUAL MODE' AND TOGGLING DOWN TEMPERATURE RESULTED IN A LOUD POP OR BANG THOUGHT TO BE RAPID DECOMPRESSURIZATION. A MIST FORMED IN THE CABIN, SMOKE ISSUED FROM OVERHEAD VENTS, AND STRONG OIL SMELL UPSET OCCUPANTS. EMERGENCY DECLARED. UNEVENTFUL LANDING ACCOMPLISHED. FWD EVAPORATOR FOUND RUPTURED IN CAPILLARY/COOLING FIN AREA IN CENTER OF EVAPORATOR. FURTHER INVEST FND AIR COND SUCTION AND DISCHARGE LINES INSTALLED REVERSED WHEN REPLACED WITH NEW 4.5 HRS PREVIOUSLY. REPAIR STATION REPLACED HOSE, INSPECTOR DOUBLE INSPECTED.