Checking Air Intake System

IMPORTANT: The air intake system must not leak. Any leak, no matter how small, may result in internal engine damage due to abrasive dirt and dust entering the intake system.

1. Inspect all intake hoses (piping) for cracks. Replace as necessary.

2. Check clamps on piping which connect the air cleaner to the engine. Tighten clamps as necessary. This will help prevent dirt from entering the air intake system through loose connections, causing internal engine damage.

3. 
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   Rubber Dust Unloader Valve

   A - Dust Unloader Valve

   If engine has a rubber dust unloader valve (A), inspect the valve on bottom of air cleaner for cracks or plugging. Replace as necessary.

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4. 
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   Air Restriction Indicator

   B - Air Restriction Indicator

   Test air filter restriction indicator (B) for proper operation. Replace indicator as necessary.

   IMPORTANT: ALWAYS REPLACE primary air cleaner element when air filter restriction indicator is torn or visibly dirty, or when it exceeds specifications or service interval. A clogged air cleaner element will cause excessive intake restriction and a reduced air supply to the engine.

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5. Remove and inspect primary air cleaner element. Service as necessary. (See Replacing Air Cleaner Filter Elements in the Service As Required Section.)

   If equipped with air intake restriction indicator gauge (B), check gauge and service air cleaner if it exceeds specifications.

   Item	Measurement	Specification
   Maximum Air Intake Restriction	Vacuum	25 in. (625 mm) H2O (6.25 kPa) (0.06 bar) (1.0 psi)

   If not equipped with air filter restriction indicator, replace air cleaner elements at 500 hours or 12 months, whichever occurs first.