As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT RETURNED TO AIRPORT WITH AIR CONDITIONING PROBLEM. #1 SEAL IN #2 ENGINE FOUND LEAKING. PROBLEM IS SUSPECTED TO BE DUE TO COMPANY CAMPAIGN TO CHANGE OIL FROM EXXON 2380 TO CASTROL 5000. SEAL REPLACED AND OIL CHANGED BACK TO EXXON 2380.