What was found
APPROACHING TOP OF CLIMB (TOC) OUT OF TJSJ; DENSE WHITE SMOKE ENTERING THE COCKPIT AREA WHILE PERFORMING SMOKE SOURCE 10 CHECKLIST, SMOKE STOPPED; FLIGHT CONTINUED OK. PERFORMED T/S DC-10 M/M TAFI 21-50-00; FOUND NR 3 PACK EXHAUST DOOR STAYING CLOSED; DEFERRED NR 3 PACK, TRANSFERRED TO DMI 19590 IN ACCORDANCE WITH MEL 21-1 CAT "C" REF MEL DDG, SECURED CLOSED THE PACK CONTROL VALVE AS PER MEL/DDG. AS PER TAFI M/M 21-50-00 FOUND NR 3 PACK ANTI-ICE VALVE STOCK OPEN. REMOVED AND REPLACED VALVE SEPARATOR COACESCER BAG IN ACCORDANCE WITH M/M 21-50-03. OPERATIONAL CHECK SYSTEM INDICATOR IN ACCORDANCE WITH M/M 21-00-00. CLEARED DMI NR 19590.