SDR 99ZZZX2789

Service difficulty report · Gasket · Piper PA31350

Difficulty date: June 30, 1999
Submitted: March 26, 2000
Operation: General aviation
Aircraft: N728CA
Make and model: Piper PA31350
Aircraft serial: 317952036
System (JASC): 7921 · Engine Oil Cooler
Part: Gasket
Part number: 76510
Condition: Mismanufactured
Location: Bypass Valve
Part time: 100 hours
Component: 53E22144
Stage of operation: IN
Nature of condition: W
Precautionary procedure: K

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

WHEN C/W LYCOMING MSB 518C ON INSPECTION OF THERMOSTATIC BYPASS VALVE, UPON RE-INSTALLING VALVE, NEW GASKET WOULD NOT SIT ON VALVE CORRECTLY. IT SITS ON TAPERED SECTION OF VALVE AND WHEN TORQUED DOWN, IT LEAKS. IF THE INSIDE DIAMETER OF THE GASKET WAS CHAMFERED ON BOTH SIDES, GASKET WOULD FIT PROPERLY.

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