IO-390-D Series Engine Maintenance Manual
12-30
© 2020 Avco Corporation. All Rights Reserved
Page 94
March 2020
IO-390-D Series Engine Maintenance Manual
Table 1 (Cont.)
Fault Isolation Guide
Problem
Cause
Corrective Action
Ref.
Excessive oil
consumption
(Cont.)
Worn valve guides
1.
Measure the valve guides for wear
as per instructions in the section
“Exhaust Valve and Guide
Inspection.”
2.
Replace worn valve guides.
72-30
Oil leaks
Examine the external area of the
engine for leaks, identify and correct
the cause of any leak.
Oil siphoned from
engine during flight
1.
Verify that the oil filler cap is
secure and has either safety wire or
cable, and the oil access door
closes correctly.
2.
Make sure that the breather tube is
accurately cut and the crankcase
ventilation system is installed
correctly per the airframe
manufacturer’s instructions.
12-10
Oil level too high
Do not fill above the maximum oil
sump capacity.
IOM
Appendix A
Drain some oil (start of “Oil Change
Procedure.”)
12-10
High oil
temperature
Cooling baffles are
missing, broken, or
incorrectly installed
Ensure that all baffles are installed
correctly and none are broken.
Replace as necessary.
NOTICE:
Never modify, relocate, or
eliminate any cooling baffles.
Oil level is too low
Complete the “Oil Level Check” at
regular intervals. Keep oil at the
specified level.
12-10
Incorrect grade of oil
Use the correct grade of oil per the
latest revision of Service Instruction
No. SI-1014..
