# SDR CA000720009

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 20, 2000
- Submitted: July 24, 2000
- Operation: General aviation
- Make and model: Cessna 152
- Registry model: [Cessna 152](https://openairdocs.org/model/cessna-152) (OpenAirDocs)
- Aircraft time: 7,283 hours
- Engine: Lyc O235L2C
- System (JASC): [7100 · Powerplant System](https://openairdocs.org/jasc/7100)
- Part: O-Ring
- Condition: Wrong Part
- Location: Case/Stud
- Stage of operation: IN
- How discovered: V
- Nature of condition: K
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CA000720009

## Discrepancy

(CAN) DURING TROUBLESHOOTING FOR AN ENGINE OIL LEAK, IT WAS DETERMINED THAT OIL WAS SEEPING OUT THE CENTER THROUGH-BOLT STUDS; ENGINE AND CRANKCASE WAS DISASSEMBLED FOR ACCESS TO THE THROUGH-STUD O-RINGS.  IT WAS THEN DISCOVERED THAT THE WRONG O-RINGS WERE INSTALLED ON THE 6 THROUGH-STUDS.  THE O-RINGS WERE THICKER THAN THE RECESS WAS GROOVED OUT FOR AND AS A RESULT THE 6 O-RINGS WERE SQUASHED AND STUCK IN THE MATING SURFACES OF THE CRANKCASE HALVES, WHICH RESULTED IN A LOSS OF TORQUE AND FRETTING OF THE CRANKCASE MATING SURFACES.  THE CRANKCASE HALVES NEEDED TO BE MILLED AND LINE BORED.

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