LOSS OF OIL QUANTITY AND PRESSURE RESULTS IN B757-200 DIVERSION.

Narrative

APPROX 240 NM E OF ZZZ; WHILE ON COURSE; I NOTED THAT THE OIL QUANTITY FOR THE L ENG WAS READING ZERO. ALL OTHER ENG PARAMETERS WERE NORMAL AND MIRRORED THE READINGS OF THE R ENG. THE L ENG OIL PRESSURE WAS OBSERVED TO READ 189 PSI. THE CAPT INSTRUCTED ME TO SEND AN ACARS MESSAGE TO MAINT CTL CONCERNING OUR OBSERVATION; I DID. WE RECEIVED A REPLY FROM MAINT CTL STATING TO: WATCH THE OIL TEMP AND PRESSURE; MAKE SURE THEY REMAIN NORMAL. QUANTITY IS MOST OFTEN AN INDICATOR PROB. ENG HAS NOT BEEN USING OIL. DO NOT SEE ANYTHING IN RECENT HISTORY. ENTER A GRIPE FOR MAINT SO WE CAN CHK IT OUT. WE DID AS REQUESTED. THE CAPT CHKED AND SHARED THE FLT MANUAL VERBIAGE. IT READ: INFLT; SUFFICIENT OIL IS AVAILABLE TO CONTINUE OPERATING THE ENG EVEN IF OIL QUANTITY READS ZERO. HOWEVER; EXCEEDING THE LOW OIL PRESSURE RED LINE LIMIT REQUIRES ENG SHUTDOWN. WE CONTINUED TO OBSERVE THE OIL PRESSURE AND WERE PREPARED IF NECESSARY TO SHUT THE ENG DOWN. WE DISCUSSED USING ZZZ AS POSSIBLE DIVERT STATION SINCE IT WAS FAMILIAR TO BOTH OF US. IT WAS STRAIGHT AHEAD AND THE WX WAS CLR. ABOUT THIS TIME WE NOTED THAT THE OIL PRESSURE ON THE L ENG WAS BEGINNING TO DECREASE SLOWLY. IT WAS CONSISTENTLY DECREASING. IT WAS APPARENT TO BOTH OF US THAT A DIVERT WAS NOW NECESSARY. CAPT ASKED ATC FOR A DSCNT CLRNC TO ZZZ DUE TO AN OIL PRESSURE PROB. THE CAPT ASSUMED THE PF DUTIES AND BEGAN A NORMAL DSCNT. I REPROGRAMMED THE FMC FOR A ZZZ DEST; GOT THE ATIS; AND BEGAN SETTING THE COCKPIT UP FOR AN ILS APCH TO ZZZ. THE CAPT STARTED THE APU. DURING THE DSCNT IT BECAME NECESSARY TO SHUT THE ENG DOWN BECAUSE THE OIL PRESSURE WAS APCHING THE RED LINE. USING THE FM PROC THE L ENG WAS SECURED. AN EMER WAS DECLARED WITH ATC. TOUCHDOWN OCCURRED AT APPROX 1200 FT FROM THE END OF THE RWY. WE WERE CLRED TO OUR TERMINAL. RAMP CLRED US TO OUR GATE; THE FIRE EQUIP FOLLOWED US TO OUR GATE.