Service Bulletin No. 524

(Supersedes Service Bulletin No. 381, Service Bulletin No. 385, Service Bulletin No. 454B, Service Bulletin No. 455D, and Service Bulletin No. 456F)

DATE: September 1, 1995

MODELS AFFECTED

See attached Lists I and II for specific models and serial numbers. All new, overhauled and remanufactured engines shipped from the factory after March 31, 1985 are in compliance with this Service Bulletin.

TIME OF COMPLIANCE

I. Sintered Iron Oil Pump Impellers. Within next 25 hours of operation for engines which have sintered iron oil impellers and have not complied with any revisions to Service Bulletin No. 454, No. 455, or No. 456.

II. Aluminum Oil Pump Impellers. At next recommended overhaul not to exceed 2000 hours (2400 hours for O-235 series engines with extended TBO) of operation for engines which have steel aluminum impellers installed or have complied with revisions to Service Bulletin No. 455, or No. 456.

Textron Lycoming requires replacement of all sintered iron oil pump impellers within the next 25 hours of operation. Sintered iron impellers being replaced are P/N 77313, P/N 78532, P/N LW-12897, P/N LW- 14038, P/N LW-14712 and P/N LW-15863. They can be identified by a porous surface finish on the impeller faces (refer to Figure 3). Engines from the attached List I with sintered iron impellers which are not in compliance with any revisions to Service Bulletin No. 454, No. 455, or No. 456 must have kit, P/N 05K19423-S installed within the next 25 hours of operation.