What was found
AFTER LANDING, NR 1 ENG OIL FILTER BYPASS LIGHT ILLUMINATED. QRH 7.9 COMPLETE. ACFT GROUNDED. CHECKED CDU REF FIM TASK 79-05- FOUND NR 1 ENG BITE FAULT MESSAGE 79-31121. THE OIL FILTER SIGNALS DISAGREE FOR THREE FLT LEGS. BEGAN FIM 79-05-817, STEP E AND G, FILTERS CLEAN. COMPLETED FIM 79-05-817 STEP H. NO LEAKS CONFIRMED. NR 1 ENGINE SCAVENGE OIL FILTER BOWL CAP FROZEN IN PLACE. REPLACED NR 1 ENG SCAVENGE OIL FILTER ASSY IAW MM 79-21-04-000-801 AND AMM 79-21-04-400-801 STEPS F.(1)- G(4). COMPLETED STEPS H AND I, REF MM 79-21-04-400-801, LEAK & OPS CHECKED GOOD.