IO-390-D Series Engine Maintenance Manual
12-10
© 2020 Avco Corporation. All Rights Reserved
Page 78
March 2020
IO-390-D Series Engine Maintenance Manual
Table 3
Guidelines for Particle Quantity and Size on Oil Filter or Oil Suction Screen
Condition
Corrective Action
(Table 4)
1 to 9 pieces of metal (1/16 in. (1.2 mm)) diameter or less)
Continue to operate the
engine until the next
scheduled oil change
10 to 20 pieces of shiny flake-like, non-magnetic metal (1/16 in. (1.2
mm)) diameter or less)
Corrective Action 1
10 or fewer short hair-like pieces of magnetic metal
Corrective Action 1
20 to 40 pieces of shiny flake-like non-magnetic metal
Corrective Action 2
45 to 60 small pieces of shiny flake-like, nonmagnetic metal
Corrective Action 3
Pieces of metal that are chunks, greater than 3/16 in. (4.8 mm) or chips
smaller than chunks
NOTICE:
A mixture of magnetic and nonmagnetic material can
indicate valve or ring and piston failure.
NOTICE:
Remove the bottom spark plugs to identify a non-
conforming cylinder.
Corrective Action 4
1/4 teaspoonful or more of nonmagnetic plating with or without a
copper tint, could vary in sizes
Corrective Action 2
1/4 teaspoonful or more of nonmagnetic plating with or without a
copper tint, 1/16-inch or larger size could indicate bearing damage
Corrective Action 4
Pieces of shiny flake-like, nonmagnetic metal (larger than 1/16 inch in
diameter) with no copper tint. (Possible indication of incorrect propeller
operation.)
Corrective Action 4
1/4 teaspoonful of nonmagnetic brass or copper colored metal that
appears coarse like sand
Corrective Action 4
1/2 teaspoonful of more of metal
Corrective Action 4
