# SDR 2015FA0000306

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 1, 2015
- Submitted: July 1, 2015
- Operation: General aviation
- Aircraft: [N342EA](https://openairdocs.org/aircraft/N342EA), registered now
- Make and model: Cessna U206G
- Registry model: [Cessna U206G](https://openairdocs.org/model/cessna-u206g) (OpenAirDocs)
- Aircraft serial: U20606197
- Aircraft time: 11,560 hours
- Engine: Cont IO550N
- Engine time: 442 hours
- Propeller: Hartzl PHCJ3YF1
- System (JASC): [8550 · Reciprocating Engine Oil System](https://openairdocs.org/jasc/8550)
- Part: Crankcase
- Part number: 6525423
- Condition: Cracked
- Location: Engine
- Stage of operation: NR
- How discovered: O
- Nature of condition: K
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2015FA0000306

## Discrepancy

IN THE PREVIOUS SEVERAL WEEKS, AN OIL LEAK WAS IDENTIFIED COMING FROM SOMEWHERE BEHIND THE OIL DIPSTICK/FILLER TUBE. IT WAS THOUGHT THAT A GASKET BETWEEN THE TUBE ASSEMBLY AND THE CRANKCASE WAS LEAKING SO IT WAS REPLACED. OIL CONTINUED TO LEAK SO THE NR 2 CYLINDER WAS REMOVED TO INVESTIGATE A POSSIBLE CYLINDER BASE SEAL LEAK. DURING THE PROCESS OF REMOVING AND PREPARING TO REINSTALL THE CYLINDER, A CAREFUL VISUAL INSPECTION REVEALED A CRACK BELOW THE SEVENTH STUD BOSS BETWEEN CYLINDER NR 2 AND 4. FURTHER EXAMINATION REVEALED THAT THE CRACK WAS ALSO VISIBLE INSIDE THE NR 2 CYLINDER PORT ON THE MAIN BEARING BOSS BETWEEN CYLINDER NR 2 AND CYLINDER NR 4.

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