What was found
AFTER TAKEOFF, WHILE CLIMBING OUT OF 6000', RED MASTER WARNING LIGHT ILLUMINATED AND LO OIL PRESS L LIGHT WAS FLASHING. L OIL PRESS GAUGE WAS CHECKED AND INDICATED O PSI. EMERGENCY CHECKLIST ACCOMPLISHED AND L ENGINE WAS SHUTDOWN. ENGINE, SN PCE-DB00655; PERFORMED INITIAL TROUBLESHOOTING- INSPECTED OIL FILTER AND OIL FILTER AND COLD START VALVE WITH NO DEFECTS IAW MM 79-20. REMOVED LT ENGINE OIL PUMP, PN 30J2705-02, SN 43A315 587 HOURS IAW MM CH 79-20-02. ENGINE STILL HAS NO OIL PRESSURE, REMOVED ENGINE, SN PCE-DB0655 AND INSTALLED A REPAIRED ENGINE SN PCE-DB0494 IAW MM CH 71-00-03. AND THE MM 71-00-03.