Note: The air filter indicators need annual replacement.
Use an air filter restriction indicator (Illustrations 6 and 7) to determine when a filter should be replaced. The two types of restriction indicators are the flag type and the graduated type.
Illustration 6 g01158832
These graduated restriction indicators are found on newer engines.
Illustration 7 g01158835
A flag type air filter restriction indicator (older style).
Inspect the indicators daily for cracks, holes, or loose fittings. If the indicator is damaged, the indicator must be repaired or replaced when any of these conditions are present.
See the appropriate Operation and Maintenance Manual for further information.