Service difficulty report · Gasket · Cessna 421C

Difficulty date
March 22, 2012
Submitted
April 27, 2012
Operation
General aviation
Aircraft
N421AZ
Make and model
Cessna 421C
Aircraft serial
421C0401
Engine
Cont GTSIO520*
Part
Gasket
Part number
635823
Condition
Failed
Location
Oil Cap
Stage of operation
IN
How discovered
V
Nature of condition
O
Precautionary procedure
K

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

What was found

OIL FILLER CAP GASKET ON ENGINE. HAVE REPLACED THE GASKET TWO TIMES DUE TO DISTORTION AND TORN. GASKET MATERIAL LACKS STABILITY FOR THE TWISTING FORCE IT IS SUBJECTED TO. THE MATERIAL SQUEEZES OUT OF PLACE AND WINDS UP IN THE WINGS OF THE CAP. THIS CAUSES AN OIL SEEP. THE FACTORY SENT 3 EA GASKETS AT THE 100 HUR MARK ON THE ENGINE WHEN I MADE COMMENTS TO THEM. THE 2ND ONE CHANGED WITHIN 150 HRS TIS WAS TORN. THE MATING SURFACES ARE SMOOTH. THE GASKET MATERIAL SEEMS TO BE DISPLACED BY THE SQUEEZE OF THE CAP PRESSURE TO FORCE THE GASKET INTO THE WINGS/FINGER HOLDS ON THE CAP. THIS CAUSES A LEAK. THE GASKET MATERIALIS ALSO TEARING IN THIS APPLICATION.

More about the Cessna 421C