As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU OIL MONITORING DATA SHOWS OIL CONSUMPTION TO BE TRENDING HIGHER THAN EXPECTED. GROUNDED - YES. ACCOMPLISHED APU OIL CONSUMPTION FAULT ISOLATION PER B737-800 FIM 49-95 TASK 801. FOUND SIGNS OF OIL COOLER LEAKING. REMOVED OIL COOLER AND FOUND INBOARD AIR FINS SATURATED WITH OIL. REF B737-800 AMM 49-91-41-200-801 FOR OIL COOLER INSPECTION. INSTALLED NEW OIL COOLER, LEAK CHECK GOOD. REF AMM 49-91-41. RAN APU AGAIN, NO OTHER OIL LEAKS FOUND.