Section 6.3
Defective Air Compressor

To determine if a defective air compressor is causing excessive oil consumption, perform the following: ‪

1. Perform a crankcase pressure test and record the test results. 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. Disconnect the air outlet line from the air compressor; see Figure "Air Compressor Air Outlet Line" ; refer to appropriate service manual, special equipment chapter.
   

   Figure 1. Air Compressor Air Outlet Line

3. Repeat step 1 and record the test results.
4. Compare the results of test one with test two.
   1. If the engine crankcase pressure remained the same, check the turbocharger; refer to "6.4 Defective Turbocharger" .
   2. If the engine crankcase pressure decreased, replace the air compressor; refer to "6.3.1 Air Compressor Removal" .

Section 6.3.1
Air Compressor Removal

Perform the following steps to remove the defective air compressor:‪

1. Remove the air compressor from the engine; refer to appropriate service manual, special equipment chapter.
2. Disassemble and repair the air compressor; refer to OEM guidelines.
3. Install the repaired air compressor to the engine; refer to appropriate service manual, special equipment chapter.
4. Verify repair of the air compressor; refer to "6.3.1.1 Test Engine with Repaired Air Compressor" .

Section 6.3.1.1
Test Engine with Repaired Air Compressor

Perform the following steps to determine if the repaired air compressor 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.
   1. If the engine crankcase pressure exceeds 1.25 kPa (5 in. H₂ O), refer to "6.4 Defective Turbocharger" . Shut down the engine.
   2. If the engine crankcase pressure is less than1.25 kPa (5 in. H₂ O), shut down the engine; no further troubleshooting is required.