What was found
(CAN) AFTER TAKEOFF,LOSS OF LT ENGINE OIL PRESSURE. SHUT DOWN LT ENGINE, DECLARED EMERGENCY AND RETURNED TO BASE. ENGINE SHOWED SIGNS OF OIL LEAK ON LT COWL. INVESTIGATED OIL LEAK AND FOUND THE OB OIL CAP LOOSE. INSPECTED OIL CAP/DIP STICK O-RING AND LOCKING ASSY SERVICEABLE. CLEAN DOWN ENGINE OIL SPILLAGE AND SERVICED ENGINE WITH MOBIL 254. C/O GND RUNS AND ENGINE PERFORMED SERVICEABLE. NO APPARENT LEAKS ON ENGINE. AIRCRAFT RELEASED FOR RETURN TO SERVICE.