Section 7.1
Obstruction or Damage to Rocker Cover Breather

To determine if an obstructed or damaged breather is causing excessive crankcase pressure, perform the following: ‪

1. Perform a crankcase pressure test. Refer to appropriate service manual, preventive maintenance chapter. For crankcase pressure guidelines refer to Service Information Letter 02 TS-20 found on the DDC extranet.
2. Check the results, if the engine crankcase pressure is greater than 1.25 kPa (5 in. H₂ O), replace wire mesh element. Refer to "7.1.1 Rocker Cover Breather Resolution" .

Section 7.1.1
Rocker Cover Breather Resolution

Perform the following steps to replace wire mesh element replacement:‪

1. Remove the valve rocker cover(s) (one-piece, two piece, three piece); refer to appropriate service manual, engine chapter.
2. Remove the wire mesh form the rocker cover; refer to appropriate service manual, engine chapter.
3. Install a new wire mesh element to the rocker cover; refer to appropriate service manual, engine chapter.
4. Install the rocker cover to the engine; (one-piece, two piece, three piece) refer to appropriate service manual, engine chapter.
5. Verify replacement of wire mesh element; refer to "7.1.1.1 Test Engine with New Wire Mesh Element" .

Section 7.1.1.1
Test Engine with New Wire Mesh Element

Perform the following steps to determine if the new wire mesh element resolved the excessive crankcase pressure:‪

1. Start and run the engine.
2. Perform a crankcase pressure test. Refer to appropriate service manual, preventive maintenance chapter. For crankcase pressure guidelines refer to Service Information Letter 02 TS-20 found on the DDC extranet.
   1. If the engine crankcase pressure is less than 1.25 kPa (5 in. H₂ O), no further troubleshooting is required. Shut down the engine.
   2. If the engine crankcase pressure is greater than 1.25 kPa (5 in. H₂ O), check the air compressor; refer to "7.2 Defective Air Compressor" . Shut down the engine.