Oil Contamination Check - Lycoming IO-390-D Series Maintenance Manual

IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual
5 Per Chapter 74-20, remove and examine the spark plugs.
Per Chapter 72-30, complete a "Cylinder Borescope Inspection" on the cylinders.
Remove the propeller governor to determine if metallic particles have spread to other
parts of the engine. If the contamination has spread to other parts of the engine, proceed
to Corrective Action 4.
a. Complete these procedures in Chapter 72-30:
6
• Cylinder Removal
• Piston Removal
b. Per the Connecting Rod Inspection Checklist in Chapter 72-20, examine the connecting rod
bushing
c. Complete these procedures in Chapter 72-30:
7
• Cylinder Removal
• Piston Removal
a. Per the Connecting Rod Inspection Checklist in Chapter 72-20, examine the connecting rod
bushing
b. Complete the "Piston Inspection" procedure in Chapter 72-30. Examine the pistons for wear
or damage.

17. Oil Contamination Check

NOTICE: Lycoming engine models that have a propeller governor can have a small screen molded
within the propeller governor gasket. Remove this gasket and look for particle
contamination on the propeller gasket screen. Replace with a new propeller governor
gasket.
If less than 10 metallic particles are found on
this screen:
A. Replace the propeller governor gasket.
B. Complete an oil change.
C. Replace the oil filter.
D. Complete a 20 to 30-minute operational
ground check. Refer to the aircraft POH.
E. Remove the oil filter and oil filter
element.
F. Examine the oil filter or oil pressure
screen, if the quantity of metallic particles
has increased, send the metallic particles
for analysis and proceed to Corrective
Action 5 in Table 4. If there are no
metallic particles, continue with routine
engine operation and maintenance.
© 2020 Avco Corporation. All Rights Reserved
March 2020
Table 4 (Continued)
Recommended Corrective Action Options
If 10 or more metallic particles or flakes or
slivers of metal are found on this screen:
A. It is likely that the particles have bypassed
the oil filter or oil pressure screen and have
circulated to other parts of the engine.
B. In this case, the particles could now be in
the close-tolerance gaps between the
crankshaft main bearings and crankshaft.
The crankshaft could be scored or have
heat damage due to decreased oil flow.
C. Do not continue further flight.
D. Proceed to Corrective Action 4 in Table 4.
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