What was found
AFTER TAKEOFF, OIL PRESSURE DROPPED TO 0 AND HAD SMOKE IN THE COCKPIT. SHUTDOWN ENGINE AND RETURNED TO FIELD. FLIGHT 5769. REPLACED LEFT ENGINE ASSEMBLY IAW EMB 120 MM 72-00-00. OPS CHECK GOOD. REPLACED OIL COOLER. NO LEAKS NOTED. S/N OFF: 115629, P/N 160282-6, S/N OFF 105-823.