IO-390-D Series Engine Maintenance Manual
© 2020 Avco Corporation. All Rights Reserved
12-10
March 2020
Page 77
IO-390-D Series Engine Maintenance Manual
Table 2 (Continued)
Guidelines for Identification of Metal Particulates and Chips & Corrective Action
Metals/
Alloys
Tests & Characteristics
Possible Source of Origin
on Lycoming Engine
Next Step
Lead
Bearings
If lead chips, chunks,
or balls are found,
complete Corrective
Action 4 in Table 4.
Aluminum
flakes
When placed in 50%
solution of nitric acid
and muriatic acid
(approximately 30%
hydrochloric acid and
water), or a sodium
hydroxide solution, the
aluminum particles
bubble and fizz and form
a black residue
Crankcase
Accessory housing
Oil pump body
Cylinder head
Pistons
Piston pin plugs
Oil sump baffle
Turbocharger inlet housing
Sleeve bearings
Refer to Table 3 for
the quantity and size
of the particles
Magnesium
Oil sump
Refer to Table 3 for
the quantity and size
of the particles
Tin
Soft, malleable
Not picked up by magnet
When dropped onto a
hot (500◦F) soldering
iron, tin particle will
melt and fuse with 50/50
solder
Tin-plated parts
Refer to Table 3 for
the quantity and size
of the particles
Cadmium
Plating
Refer to Table 3 for
the quantity and size
of the particles
Zinc
Plating
Refer to Table 3 for
the quantity and size
of the particles
