What was found
(CAN) REPORT FROM CREW, FLIGHT WAS ON ASCENT TO FL160, ABOVE FL100, CREW NOTICED OIL TEMP OF 122 FLT LEVELED OFF AT FL120, IAW QRH REDUCED POWER 20 NR, AFTER 10 MINUTES OIL TEMP WAS 123-124. IAW QRH SHUTDOWN NR 1 ENGINE AND RETURNED TO BASE. EMERGENCY DECLARED. F/A AND PAX BRIEFED, FLIGHT LANDED SAFELY AND WAS TOWED TO GATE. ACOC BY-PASS VALVE PN: D2887-355C REPLACED.