Initial Run-In Procedure Precautions; Routine Turbocharger Maintenance/Inspection; Absolute Pressure Relief Valve - Piper PA-44-180 SEMINOLE Maintenance Manual

INITIAL RUN-IN PROCEDURE PRECAUTIONS.

To protect the turbocharger during engine initial run-in on new or newly overhauled engines, perform the
following precautions:
1. TEMPORARILY install a screen of 100 mesh or finer in the oil supply line to the turbocharger to trap metal
particles from the engine.
BECAUSE CLEANING OF THE EXTRA SCREEN IS NOT PROVIDED FOR
IN THE PERIODIC INSPECTION GUIDE, THE SCREEN MUST NOT BE
LEFT IN PLACE AFTER THE INITIAL RUN-IN PERIOD OPERATION OF
THE TURBOCHARGER WITH A CLOGGED SCREEN WILL CAUSE
TURBOCHARGER FAILURE DUE TO A LACK OF LUBRICATION.
2. Upon completion of the initial run-in period, remove the screen from the oil supply line.
ROUTINE TURBOCHARGER MAINTENANCE.
PERIODIC INSPECTION.
Whenever routine service of the engine is performed, inspect the turbocharger as follows:
1. Inspect all components of the air induction system for loose connections, cuts, cracks, punctures, corrosion
or other evidence of deterioration.
2. Check the air duct connection between the compressor and the engine intake manifold and between the
intake manifold and engine.
3. Ensure that the engine air cleaner has been inspected and serviced.
4. Inspect the exhaust system for leakage.
5. Disconnect the exhaust ducting from the turbine outlet and examine the turbine wheel blades for damage.
Check for oil in the turbine wheel housing indicating seal leakage. Check for evidence of wheel rub on the
housing.
6. Inspect for oil leakage at the turbocharger center housing oil inlet and drain port connections.
7. Check the engine crankcase breather for restrictions to air flow. Correct as required.

ABSOLUTE PRESSURE RELIEF VALVE.

The absolute pressure relief valve is mounted on the duct between the compressor outlet and the engine intake
manifold. Deck pressure acting upon an aneroid bellows opens the valve at a predetermined value thereby
limiting any possible damaging overboost.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
3J13
8 1 - 2 6 - 0 0
Page 81-11
Revised: May 15, 1989