As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A LEAK WAS FOUND ON THE #1 ENGINE HMU DURING POST MAINTENANCE GROUND RUNS. IT WAS DETERMINED TO HAVE A SUSPECTED CRACK OR LEAKING FROM THE SPLIT LINE OF THE HMU. THE AREA WAS TOO CONGESTED TO VISUALLY SEE A CRACK OR WHERE THE LEAK WAS COMING FROM. REMOVED AND REPLACE THE HMU CORRECTED THE DISCREPANCY.