As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 3978 DURING CRUISE THE CAPTAIN REPORTED, NR 1 ENGINE STARTED LOSING OIL AFTER DEPARTURE. ELECTED TO DIVERT TO GRR DUE TO OIL LEVEL WENT FROM 9 QUARTS TO 3 QUARTS. IT WAS AN OVERWEIGHT LANDING BUT WAS WELL UNDER THE 360 FEET PER MINUTE SINK RATE. THE AIRCRAFT WAS REMOVED FROM SERVICE. THE CORRECTIVE ACTION INFORMATION IS PENDING.