What was found
IMMEDIATELY AFTER TAKEOFF SMELLED AND SAW SMOKE IN THE COCKPIT MOVING FROM LT TO RT ACROSS THE PILOT'S SEAT. REMOVED AND REPLACED LT ENGINE IAW 750 MM 71-00-03 & MM 72-00-00. OPS & LEAK CHECKED GOOD. CHANGED ENGINE AND APU, OIL LEAK OF CARBON SEAL CREATING SMOKE IN THE COCKPIT. ENGINE WAS RETURNED FROM SERVICE DUE TO "ODOR IN CABIN" AND REPAIRED, MODIFIED & TESTED IAW ENG MANUAL CSP31010, REV 29. OIL & FUEL FILTERS CHANGED AFTER TEST. LONG TERM PRESERVATION IAW EM 72-00-00-500-805 COMPLIED WITH. REPLACED THE PAIN SEAL (COMPRESSOR SEAL).