903D Compact Wheel Loader Caterpillar

Some engines are equipped with a differential gauge for inlet air pressure. The differential gauge for inlet air pressure displays the difference in the pressure that is measured before the air cleaner element and the pressure that is measured after the air cleaner element. As the air cleaner element becomes dirty, the pressure differential rises.

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Air filter service indicator (1)

Inspect

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The air filter service indicator is located near the air filter housing.

Observe the air filter service indicator. The air cleaner element should be cleaned or the air cleaner element should be replaced when one of the following conditions occur:

• The yellow diaphragm enters the red zone.

• The red piston locks in the visible position.

Test

1. Check for ease of resetting. The service indicator should reset in fewer than three pushes.

2. Check the movement of the yellow core when the engine is accelerated to the engine rated speed. The yellow core should latch approximately at the greatest vacuum that is attained.

3. If the service indicator does not reset easily, or if the yellow core does not latch at the greatest vacuum, the service indicator should be replaced. If the new service indicator will not reset, the air line for the service indicator may be plugged.

Replace

Replace the service indicator if the following conditions exist:

• The machine is used in a severely dusty environment.

• The engine is overhauled.

• Major components are replaced.

Replace the service indicator annually regardless of the operating conditions.

Note: When a new service indicator is installed, excessive force may crack the top of the service indicator. Tighten the service indicator to a torque of 2 N·m (18 lb in).