As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4336 THE CREW REPORTED A STRONG OILY ODOR IN THE COCKPIT DURING FLIGHT AND THE STRONGEST ODOR OCCURRING DURING TAKEOFF ALT-TO -1 PACKS ON. THE AIRCRAFT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED ENGINE NUMBER 1 IAW AEWC 71-000-00O. OPERATIONAL AND LEAK CHECKS WERE GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE. THE CAUSE OF THE ODOR/LEAK WAS DETERMINED TO BE A FAULTY NR 4 CARBON SEAL.