Service Instruction No. 1255 A
Thermostatic Oil Cooler Valve Replacement
Supersedes Service Instruction No. 1255
May 13, 2016
Lycoming engines using thermostatic oil cooler bypass valve
TIME OF COMPLIANCE
At 100-hour inspection or when high oil temperature is noted
REASON FOR REVISION
Updated bypass valve replacement part numbers; added respective detailed bypass valve replacement instructions for engines with oil pressure screens and oil filters
This revision of the Service Instruction identifies thermostatic oil cooler bypass valve P/N 53E22144 (Figure 1) (or other superseding bypass valve identified in the latest revision of Service Instruction SI-1565) as a superseding replacement bypass valve for either bypass valve P/N LW-10269 or P/N 75944.
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