Inspecting the Air Cleaner Element
Notice: All air intake components and connections must be air- and water-tight. Dirt or dust entering the engine can cause internal engine damage. Most of the dirt and dust particles are silicates, which fuse into abrasive glass-like particles when exposed to engine combustion. These particles can grind piston rings, pistons, and cylinder liners. Do not operate the engine with the air filter element or any air intake component removed.
Important: Due to the variety of possible driving conditions (dirt roads, paved roads, etc.), it is critical to check the air restriction indicator, if so equipped. If the vehicle is not equipped with an air restriction indicator, inspect all components of the air intake system and air filter every six months. Replace the air filter every 12 months, or when filter restriction reaches 25 inH 2O for Cummins diesel engines, or when the air restriction indicator is completely red for gasoline and Detroit™ diesel engines (if equipped with an air restriction indicator). More frequent inspections and/or filter replacement may be needed if the vehicle is being operated in a dusty environment, to avoid damaging the vehicle.
Notice: All air intake components and connections must be air- and water-tight. Dirt or dust entering the engine can cause internal engine damage. Most of the dirt and dust particles are silicates, which fuse into abrasive glass-like particles when exposed to engine combustion. These particles can grind piston rings, pistons, and cylinder liners. Do not operate the engine with the air filter element or any air intake component removed.
Important: Due to the variety of possible driving conditions (dirt roads, paved roads, etc.), it is critical to check the air restriction indicator, if so equipped. If the vehicle is not equipped with an air restriction indicator, inspect all components of the air intake system and air filter every six months. Replace the air filter every 12 months, or when filter restriction reaches 25 inH 2O for Cummins diesel engines, or when the air restriction indicator is completely red for gasoline and Detroit™ diesel engines (if equipped with an air restriction indicator). More frequent inspections and/or filter replacement may be needed if the vehicle is being operated in a dusty environment, to avoid damaging the vehicle.
Notice: Use the air intake restriction gauge rather than visual inspection to determine if servicing the air filter element is necessary. Removal of the air filter element can cause damage to the primary seal, which may allow contaminants into the engine, potentially causing engine damage.
Important: Removal and visual inspection of the air filter should only occur if the vehicle is not equipped with an air restriction indicator.
Remove and visually inspect the air filter for holes, tears, cracks, or other damage at the recommended interval. Remove loose debris, such as leaves or pine needles, from the filter housing. If the air filter is damaged, replace it. See Safety Precautions of the Walk-In Van Workshop Manual for removal and installation instructions, or take the vehicle to an authorized Freightliner dealer.
Engine damage can occur if the air intake system is not properly maintained. Use the air intake restriction indicator to check for air intake system damage or leaks. See Fig. and Fig.. Make sure the engine is off and note the existing reading on the indicator. Reset the indicator by pushing it down. See Fig. and Fig.. Start the engine and take a short test drive. Check the indicator again and note the level of restriction on the indicator. A decrease from the previous level of restriction or a very low air restriction indicator reading (0 to 4 inH 2O) could indicate an air intake system problem such as a damaged air filter, loose or disconnected air intake piping, or a disconnected or damaged air restriction indicator.
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Partial Restriction
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Full Restriction
Fig. 1, Air Restriction Indicator, Cummins Diesel Engines
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Partial Restriction
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Full Restriction