Service Instruction No. 1008 C

July 21, 2016

MODELS AFFECTED

All O-320, IO-320, O-340, O-360, IO-360, VO-360, HIO-360, IVO-360, O- 540, IO-540, IO-720, and TIO-541 engines that do not have a Thermostatic Oil Cooler Bypass Valve Assembly installed

TIME OF COMPLIANCE

Optional, at owner's discretion

REASON FOR REVISION

Updated required parts in Table 1; clarified procedure

This Service Instruction includes a procedure to install a thermostatic oil cooler bypass valve as a replacement for a pressure-operated bypass valve. This revision of the Service Instruction identifies thermostatic oil cooler bypass valve part number (P/N) 53E22144 as the current thermostatic oil cooler bypass valve approved for use in affected Lycoming engine models (unless otherwise identified in the latest revision of Service Instruction No. SI-1565). This procedure requires the oil pressure screen housing used with a pressure-operated bypass valve be replaced by oil pressure screen housing P/N 69510.