As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ODOR OF FUMES EMITTED INTO COCKPIT SUDDENLY AT CRUISE. TURNING OFF COCKPIT A/C PACK STOPPED THE FUMES. INSPECTED COALESCERS & FOUND TO BE DIRTY. REMOVED DUCTING FOR FWD & AFT ACM TURBINES & FOUND DIRTY. FOUND AFT ACM TURBINE WILL NOT SPIN FREELY. R & R AFT ACM. ACM OPS & LEAK CHECKED GOOD IAW MM 21-50-00.