Section 7.2
Defective Air Compressor

To determine if a defective air compressor is causing excessive crankcase pressure, perform the following: ‪

1. Perform a crankcase pressure test, refer to appropriate service manual, preventive maintenance chapter and record the test results. 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 "7.3 Defective Turbocharger" .
   2. If the engine crankcase pressure decreased, repair the air compressor; refer to "7.2.1 Air Compressor Repair" .

Section 7.2.1
Air Compressor Repair

Perform the following steps to repair the defective air compressor:‪

1. Remove the air compressor from the engine; refer to appropriate service manual, special equipment chapter.
2. Install the repaired air compressor to the engine; refer to appropriate service manual, special equipment chapter.
3. Verify repair of the air compressor; refer to "7.2.1.1 Test Engine with Repaired Air Compressor" .

Section 7.2.1.1
Test Engine with Repaired Air Compressor

Perform the following steps to determine if a 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. For crankcase pressure guidelines refer to Service Information Letter 02 TS-20 found on the DDC extranet.
   1. If the engine crankcase pressure is within 1.25 kPa (5 in. H₂ O), no further troubleshooting is required. Shut down the engine.
   2. If the engine crankcase pressure is not within 1.25 kPa (5 in. H₂ O), check the turbocharger, refer to "7.3 Defective Turbocharger" . Shut down the engine.