As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INTALLED REPAIRED ENGINE ON AIRFRAME AND WERE DOING GROUND CHECKS AND HAD A LEAK BETWEEN THE MO1 HSG AND THE OIL FILTER BASE. REMOVED OIL FILTER BASE FOR MO1 HSG AND FOUND 2 SMALL O-RINGS MISSING. REPLACED ALL OF THE O-RINGS IN THE OIL FILTER BASE AND INSTALLED OIL FILTER BASE ON THE MO1 HSG AND GROUND RAN ACFT. NO LEAKS AT THIS TIME.