Lycoming YO-233-B2A Maintenance Manual page 90

Guidelines for Particle Quantity and Size on Oil or Oil Suction Screen
Condition
Chunks (3/16-inch or larger) in oil suction
screen
Bronze chips in the oil suction screen
More than five bronze chips found in the oil
filter or oil suction screen
More than three bronze chips AND more
than three aluminum chips found in the oil
filter or oil suction screen
1/4 teaspoon or more of metallic particles
and metal has gotten past the oil filter
1/4 teaspoon or more of metallic particles
and metal has not gotten past the oil filter
If the cause of the metal contamination cannot be identified, speak with the Lycoming Engines
Product Support.
If there is unusual aluminum, bronze, or iron contamination in the oil, make sure you have a full
description of the engine model, serial number, history, oil temperatures, oil pressure, unusual
performance, and properties of the metal contamination (color, size, metallic/nonmetallic, shape,
etc.). This information will help Product Support identify the cause of the contamination.
Coordinate with an appropriate oil analysis laboratory to have the material analyzed. For factory
new, factory rebuilt or factory overhauled Lycoming engines within their hourly or 12 year required
TBO cycle, if directed, send the oil filter element and metallic material to Lycoming Engines for
analyses.
A change in the usual wear rate of a part is not necessarily an indication of imminent failure. It is an
indication that a borescope examination, cylinder compression pressure check, etc. are necessary to
identify the cause for unusual wear.
12-10
Page 70
YO-233-B2A Engine Maintenance Manual
TEO-540-A1A Engine Maintenance Manual
Table 4 (Continued)
Source of Particles
Valve
Tappet
Ring
Piston
Bearing
Machining chips
Connecting rod bushing
Connecting rod bushing
Connecting rod bushing
and piston
Cylinders
Bearings
Piston
Piston pin plugs
Possibly only one
engine cylinder is
damaged or spark plug
is worn or damaged
© 2021 Avco Corporation. All Rights Reserved
Corrective Action
(Table 5)
Corrective Action 3
and contact Lycoming
Product Support
Corrective Action 6
Corrective Action 6
Corrective Action 7
Corrective Action 4
Corrective Action 5
February 2021