What was found
THE CREW REPORTED THAT DURING DECENT, CABIN FILLED WITH A HEAVY OILY SMELLING HAZE, SAME CONDITION WAS ALSO EXPIERENCED ON THE FLIGHT DECK. ACFT LANDED WITHOUT INCIDENT. REMOVED FROM SERVICE. PERFORM LT ENGINE BORESCOPE THRU NL PROBE & HP VALVE OF THE INTER COMPRESSOR CASE AND FOUND OIL ON THE WHOLE AREA. R & R LT ENGINE. PERFORMED ENGINE RUN PROCEDURES IAW JIC OPT 72-00-00 OPT 10000. OIL IN COCKPIT AND CABIN STILL PERSISTED. DUE TO SMOKE ODOR IN ACFT, R & R P2.5/P3 VALVE ASSY ON LT ENGINE IAW MM-72-30-00, ADDED TOTAL OF 3 WASHERS TO SHAFT. THE ACFT WAS RETURNED TO SERVICE.