What was found
ON FLIGHT 4537 AFTER TAKEOFF, CREW REPORTED A BURNING ODOR IN COCKPIT & JUST BEHIND COCKPIT DOOR. CREW DECLARED AN EMERGENCY & RETURNED TO RDU. UPON POWER REDUCTION PRIOR TO LANDING, ODOR WENT AWAY. PERFORMED OVERWEIGHT LANDING AT 43000 LBS AT 300 FT/MIN. ACFT LANDED WITHOUT INCIDENT. ACFT REMOVED FROM SERVICE. PERFORMED OPS TESTS OF BOTH ENGINES IAW RMM 72-00-00 & ETN EN 72-034R4. ODOR EVENT TROUBLESHOOTING COULD NOT DUPLICATE, NO ODOR IN COCKPIT OR CABIN AT THIS TIME. NO PARTS REMOVED OR REPLACED. FOUND EVIDENCE OF OIL AT SIX O’CLOCK BEHIND IGV’S IN ENGINE NR 1 INLET. R & R LT ENGINE. ACFT RETURNED TO SERVICE. THE CAUSE OF THE ODOR/LEAK WAS DETERMINED TO BE A FAULTY NR 4 CARBON SEAL.