Service Instruction No. 1423 A

Thermostatic Oil Cooler Bypass Valve Part Number

  • Publications

Supersedes Service Instruction No. 1423

May 13, 2016


All Lycoming engines using Thermostatic Oil Cooler Bypass Valve Part Number (P/N) 75944


Before next flight REASON FOR REVISION: Loctite® procedure for crimp nut is no longer valid. New superseding part number for thermostatic oil cooler bypass valve.

This revision of the Service Instruction identifies a change: Thermostatic oil cooler bypass valve part number P/N 53E22144 now supersedes P/N 75944 when it is necessary to replace bypass valve P/N 75944 if it is damaged, its crimp nut (Figure 1) is loose, or for any other reason.

Product Support Network

Wherever you are in the world, you have access to exceptional expertise and knowledge about Lycoming engines. Get the most comprehensive customer service and support in the general aviation industry.

Find a Service Center

Every Lycoming Service Center can help keep your engine up to date with all Service Instructions.