As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HISSING AIR SOUND AT 16F EXIT DOOR. GROUNDED - YES. AIR TURNBACK - INSPECTED 16F WINDOW VERIFIED NO STREAKING OR MOISTURE INSPECTED EMERGENCY DOOR PRESSURE SEAL. NO DISCREPANCIES NOTED. PRESSURIZED AIRCRAFT. NO SQUEALS OR LEAKS NOTED. REF B737-9 AMM 52-22-00.