# SDR 98ZZZX3996

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 22, 1998
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: [N745CA](https://openairdocs.org/aircraft/N745CA), registered now
- Make and model: Cessna 421C
- Registry model: [Cessna 421C](https://openairdocs.org/model/cessna-421c) (OpenAirDocs)
- Aircraft serial: 421C1043
- Engine: Cont GTSIO520L
- System (JASC): [8520 · Reciprocating Engine Power Section](https://openairdocs.org/jasc/8520)
- Part: Crankcase
- Part number: 6541194
- Condition: Mismanufactured
- Location: Engine
- Component: E199803R
- Stage of operation: IN
- Nature of condition: W
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/98ZZZX3996

## Discrepancy

APPROXIMATELY 8.0 HOURS TIS AFTER INSTALLATION, OIL OPERATING PRESSURES FELL BELOW ALLOWABLE LIMITS, ENGINE WAS REMOVED AND FOUND TO HAVE INSUFFICIENT MATERIAL THICKNESS BETWEEN AN OIL PICK-UP CAVITY AND AN OIL PUMP HOUSING STUD BOSS.  THIS CONDITION CREATED A WEAKNESS IN THE ENGINE OIL PRESSURE SYSTEM WHICH FAILED AFTER CONTINUED INTRODUCTION OF OIL PRESSURE.  AS A RESULT, OIL BEGAN TO BYPASS AT THIS POINT AND THE OIL SYSTEM COULD NOT MAINTAIN NORMAL OPERATING PRESSURES.

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